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<book id="ALSA-Driver-API">
<bookinfo>
<title>The ALSA Driver API</title>
<legalnotice>
<para>
This document is free; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
</para>
<para>
This document is distributed in the hope that it will be useful,
but <emphasis>WITHOUT ANY WARRANTY</emphasis>; without even the
implied warranty of <emphasis>MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE</emphasis>. See the GNU General Public License
for more details.
</para>
<para>
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
</para>
</legalnotice>
</bookinfo>
<toc></toc>
<chapter><title>Management of Cards and Devices</title>
<sect1><title>Card Management</title>
<!-- sound/core/init.c -->
<refentry id="API-snd-card-create">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_card_create</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_card_create</refname>
<refpurpose>
create and initialize a soundcard structure
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_card_create </function></funcdef>
<paramdef>int <parameter>idx</parameter></paramdef>
<paramdef>const char * <parameter>xid</parameter></paramdef>
<paramdef>struct module * <parameter>module</parameter></paramdef>
<paramdef>int <parameter>extra_size</parameter></paramdef>
<paramdef>struct snd_card ** <parameter>card_ret</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>idx</parameter></term>
<listitem>
<para>
card index (address) [0 ... (SNDRV_CARDS-1)]
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>xid</parameter></term>
<listitem>
<para>
card identification (ASCII string)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>module</parameter></term>
<listitem>
<para>
top level module for locking
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>extra_size</parameter></term>
<listitem>
<para>
allocate this extra size after the main soundcard structure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>card_ret</parameter></term>
<listitem>
<para>
the pointer to store the created card instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates and initializes a soundcard structure.
</para><para>
The function allocates snd_card instance via kzalloc with the given
space for the driver to use freely. The allocated struct is stored
in the given card_ret pointer.
</para><para>
Returns zero if successful or a negative error code.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-card-disconnect">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_card_disconnect</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_card_disconnect</refname>
<refpurpose>
disconnect all APIs from the file-operations (user space)
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_card_disconnect </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
soundcard structure
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Disconnects all APIs from the file-operations (user space).
</para><para>
Returns zero, otherwise a negative error code.
</para>
</refsect1>
<refsect1>
<title>Note</title>
<para>
The current implementation replaces all active file->f_op with special
dummy file operations (they do nothing except release).
</para>
</refsect1>
</refentry>
<refentry id="API-snd-card-set-id">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_card_set_id</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_card_set_id</refname>
<refpurpose>
set card identification name
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_card_set_id </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>const char * <parameter>nid</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
soundcard structure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>nid</parameter></term>
<listitem>
<para>
new identification string
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function sets the card identification and checks for name
collisions.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-card-register">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_card_register</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_card_register</refname>
<refpurpose>
register the soundcard
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_card_register </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
soundcard structure
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function registers all the devices assigned to the soundcard.
Until calling this, the ALSA control interface is blocked from the
external accesses. Thus, you should call this function at the end
of the initialization of the card.
</para><para>
Returns zero otherwise a negative error code if the registrain failed.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-component-add">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_component_add</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_component_add</refname>
<refpurpose>
add a component string
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_component_add </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>const char * <parameter>component</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
soundcard structure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>component</parameter></term>
<listitem>
<para>
the component id string
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function adds the component id string to the supported list.
The component can be referred from the alsa-lib.
</para><para>
Returns zero otherwise a negative error code.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-card-file-add">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_card_file_add</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_card_file_add</refname>
<refpurpose>
add the file to the file list of the card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_card_file_add </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>struct file * <parameter>file</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
soundcard structure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>file</parameter></term>
<listitem>
<para>
file pointer
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function adds the file to the file linked-list of the card.
This linked-list is used to keep tracking the connection state,
and to avoid the release of busy resources by hotplug.
</para><para>
Returns zero or a negative error code.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-card-file-remove">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_card_file_remove</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_card_file_remove</refname>
<refpurpose>
remove the file from the file list
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_card_file_remove </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>struct file * <parameter>file</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
soundcard structure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>file</parameter></term>
<listitem>
<para>
file pointer
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function removes the file formerly added to the card via
<function>snd_card_file_add</function> function.
If all files are removed and <function>snd_card_free_when_closed</function> was
called beforehand, it processes the pending release of
resources.
</para><para>
Returns zero or a negative error code.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-power-wait">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_power_wait</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_power_wait</refname>
<refpurpose>
wait until the power-state is changed.
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_power_wait </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>unsigned int <parameter>power_state</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
soundcard structure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>power_state</parameter></term>
<listitem>
<para>
expected power state
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Waits until the power-state is changed.
</para>
</refsect1>
<refsect1>
<title>Note</title>
<para>
the power lock must be active before call.
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>Device Components</title>
<!-- sound/core/device.c -->
<refentry id="API-snd-device-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_device_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_device_new</refname>
<refpurpose>
create an ALSA device component
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_device_new </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>snd_device_type_t <parameter>type</parameter></paramdef>
<paramdef>void * <parameter>device_data</parameter></paramdef>
<paramdef>struct snd_device_ops * <parameter>ops</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
the device type, SNDRV_DEV_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device_data</parameter></term>
<listitem>
<para>
the data pointer of this device
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>ops</parameter></term>
<listitem>
<para>
the operator table
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new device component for the given data pointer.
The device will be assigned to the card and managed together
by the card.
</para><para>
The data pointer plays a role as the identifier, too, so the
pointer address must be unique and unchanged.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-device-free">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_device_free</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_device_free</refname>
<refpurpose>
release the device from the card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_device_free </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>void * <parameter>device_data</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device_data</parameter></term>
<listitem>
<para>
the data pointer to release
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Removes the device from the list on the card and invokes the
callbacks, dev_disconnect and dev_free, corresponding to the state.
Then release the device.
</para><para>
Returns zero if successful, or a negative error code on failure or if the
device not found.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-device-register">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_device_register</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_device_register</refname>
<refpurpose>
register the device
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_device_register </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>void * <parameter>device_data</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device_data</parameter></term>
<listitem>
<para>
the data pointer to register
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Registers the device which was already created via
<function>snd_device_new</function>. Usually this is called from <function>snd_card_register</function>,
but it can be called later if any new devices are created after
invocation of <function>snd_card_register</function>.
</para><para>
Returns zero if successful, or a negative error code on failure or if the
device not found.
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>Module requests and Device File Entries</title>
<!-- sound/core/sound.c -->
<refentry id="API-snd-request-card">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_request_card</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_request_card</refname>
<refpurpose>
try to load the card module
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_request_card </function></funcdef>
<paramdef>int <parameter>card</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card number
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Tries to load the module <quote>snd-card-X</quote> for the given card number
via request_module. Returns immediately if already loaded.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-lookup-minor-data">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_lookup_minor_data</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_lookup_minor_data</refname>
<refpurpose>
get user data of a registered device
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void * <function>snd_lookup_minor_data </function></funcdef>
<paramdef>unsigned int <parameter>minor</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>minor</parameter></term>
<listitem>
<para>
the minor number
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
device type (SNDRV_DEVICE_TYPE_XXX)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Checks that a minor device with the specified type is registered, and returns
its user data pointer.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-register-device-for-dev">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_register_device_for_dev</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_register_device_for_dev</refname>
<refpurpose>
Register the ALSA device file for the card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_register_device_for_dev </function></funcdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>int <parameter>dev</parameter></paramdef>
<paramdef>const struct file_operations * <parameter>f_ops</parameter></paramdef>
<paramdef>void * <parameter>private_data</parameter></paramdef>
<paramdef>const char * <parameter>name</parameter></paramdef>
<paramdef>struct device * <parameter>device</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
the device type, SNDRV_DEVICE_TYPE_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dev</parameter></term>
<listitem>
<para>
the device index
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>f_ops</parameter></term>
<listitem>
<para>
the file operations
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>private_data</parameter></term>
<listitem>
<para>
user pointer for f_ops-><function>open</function>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>name</parameter></term>
<listitem>
<para>
the device file name
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device</parameter></term>
<listitem>
<para>
the <structname>struct device</structname> to link this new device to
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Registers an ALSA device file for the given card.
The operators have to be set in reg parameter.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-unregister-device">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_unregister_device</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_unregister_device</refname>
<refpurpose>
unregister the device on the given card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_unregister_device </function></funcdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>int <parameter>dev</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
the device type, SNDRV_DEVICE_TYPE_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dev</parameter></term>
<listitem>
<para>
the device index
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Unregisters the device file already registered via
<function>snd_register_device</function>.
</para><para>
Returns zero if sucecessful, or a negative error code on failure
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>Memory Management Helpers</title>
<!-- sound/core/memory.c -->
<refentry id="API-copy-to-user-fromio">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>copy_to_user_fromio</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>copy_to_user_fromio</refname>
<refpurpose>
copy data from mmio-space to user-space
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>copy_to_user_fromio </function></funcdef>
<paramdef>void __user * <parameter>dst</parameter></paramdef>
<paramdef>const volatile void __iomem * <parameter>src</parameter></paramdef>
<paramdef>size_t <parameter>count</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dst</parameter></term>
<listitem>
<para>
the destination pointer on user-space
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>src</parameter></term>
<listitem>
<para>
the source pointer on mmio
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
the data size to copy in bytes
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Copies the data from mmio-space to user-space.
</para><para>
Returns zero if successful, or non-zero on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-copy-from-user-toio">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>copy_from_user_toio</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>copy_from_user_toio</refname>
<refpurpose>
copy data from user-space to mmio-space
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>copy_from_user_toio </function></funcdef>
<paramdef>volatile void __iomem * <parameter>dst</parameter></paramdef>
<paramdef>const void __user * <parameter>src</parameter></paramdef>
<paramdef>size_t <parameter>count</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dst</parameter></term>
<listitem>
<para>
the destination pointer on mmio-space
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>src</parameter></term>
<listitem>
<para>
the source pointer on user-space
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
the data size to copy in bytes
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Copies the data from user-space to mmio-space.
</para><para>
Returns zero if successful, or non-zero on failure.
</para>
</refsect1>
</refentry>
<!-- sound/core/memalloc.c -->
<refentry id="API-snd-malloc-pages">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_malloc_pages</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_malloc_pages</refname>
<refpurpose>
allocate pages with the given size
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void * <function>snd_malloc_pages </function></funcdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
<paramdef>gfp_t <parameter>gfp_flags</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the size to allocate in bytes
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>gfp_flags</parameter></term>
<listitem>
<para>
the allocation conditions, GFP_XXX
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Allocates the physically contiguous pages with the given size.
</para><para>
Returns the pointer of the buffer, or NULL if no enoguh memory.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-free-pages">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_free_pages</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_free_pages</refname>
<refpurpose>
release the pages
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_free_pages </function></funcdef>
<paramdef>void * <parameter>ptr</parameter></paramdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ptr</parameter></term>
<listitem>
<para>
the buffer pointer to release
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the allocated buffer size
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Releases the buffer allocated via <function>snd_malloc_pages</function>.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-dma-alloc-pages">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_alloc_pages</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_alloc_pages</refname>
<refpurpose>
allocate the buffer area according to the given type
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_dma_alloc_pages </function></funcdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>struct device * <parameter>device</parameter></paramdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
<paramdef>struct snd_dma_buffer * <parameter>dmab</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
the DMA buffer type
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device</parameter></term>
<listitem>
<para>
the device pointer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the buffer size to allocate
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dmab</parameter></term>
<listitem>
<para>
buffer allocation record to store the allocated data
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Calls the memory-allocator function for the corresponding
buffer type.
</para><para>
Returns zero if the buffer with the given size is allocated successfuly,
other a negative value at error.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-dma-alloc-pages-fallback">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_alloc_pages_fallback</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_alloc_pages_fallback</refname>
<refpurpose>
allocate the buffer area according to the given type with fallback
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_dma_alloc_pages_fallback </function></funcdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>struct device * <parameter>device</parameter></paramdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
<paramdef>struct snd_dma_buffer * <parameter>dmab</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
the DMA buffer type
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device</parameter></term>
<listitem>
<para>
the device pointer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the buffer size to allocate
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dmab</parameter></term>
<listitem>
<para>
buffer allocation record to store the allocated data
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Calls the memory-allocator function for the corresponding
buffer type. When no space is left, this function reduces the size and
tries to allocate again. The size actually allocated is stored in
res_size argument.
</para><para>
Returns zero if the buffer with the given size is allocated successfuly,
other a negative value at error.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-dma-free-pages">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_free_pages</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_free_pages</refname>
<refpurpose>
release the allocated buffer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_dma_free_pages </function></funcdef>
<paramdef>struct snd_dma_buffer * <parameter>dmab</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dmab</parameter></term>
<listitem>
<para>
the buffer allocation record to release
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Releases the allocated buffer via <function>snd_dma_alloc_pages</function>.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-dma-get-reserved-buf">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_get_reserved_buf</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_get_reserved_buf</refname>
<refpurpose>
get the reserved buffer for the given device
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>size_t <function>snd_dma_get_reserved_buf </function></funcdef>
<paramdef>struct snd_dma_buffer * <parameter>dmab</parameter></paramdef>
<paramdef>unsigned int <parameter>id</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dmab</parameter></term>
<listitem>
<para>
the buffer allocation record to store
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
the buffer id
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Looks for the reserved-buffer list and re-uses if the same buffer
is found in the list. When the buffer is found, it's removed from the free list.
</para><para>
Returns the size of buffer if the buffer is found, or zero if not found.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-dma-reserve-buf">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_reserve_buf</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_reserve_buf</refname>
<refpurpose>
reserve the buffer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_dma_reserve_buf </function></funcdef>
<paramdef>struct snd_dma_buffer * <parameter>dmab</parameter></paramdef>
<paramdef>unsigned int <parameter>id</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dmab</parameter></term>
<listitem>
<para>
the buffer to reserve
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
the buffer id
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Reserves the given buffer as a reserved buffer.
</para><para>
Returns zero if successful, or a negative code at error.
</para>
</refsect1>
</refentry>
</sect1>
</chapter>
<chapter><title>PCM API</title>
<sect1><title>PCM Core</title>
<!-- sound/core/pcm.c -->
<refentry id="API-snd-pcm-new-stream">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_new_stream</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_new_stream</refname>
<refpurpose>
create a new PCM stream
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_new_stream </function></funcdef>
<paramdef>struct snd_pcm * <parameter>pcm</parameter></paramdef>
<paramdef>int <parameter>stream</parameter></paramdef>
<paramdef>int <parameter>substream_count</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
the pcm instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>stream</parameter></term>
<listitem>
<para>
the stream direction, SNDRV_PCM_STREAM_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>substream_count</parameter></term>
<listitem>
<para>
the number of substreams
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new stream for the pcm.
The corresponding stream on the pcm must have been empty before
calling this, i.e. zero must be given to the argument of
<function>snd_pcm_new</function>.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_new</refname>
<refpurpose>
create a new PCM instance
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_new </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>const char * <parameter>id</parameter></paramdef>
<paramdef>int <parameter>device</parameter></paramdef>
<paramdef>int <parameter>playback_count</parameter></paramdef>
<paramdef>int <parameter>capture_count</parameter></paramdef>
<paramdef>struct snd_pcm ** <parameter>rpcm</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
the id string
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device</parameter></term>
<listitem>
<para>
the device index (zero based)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>playback_count</parameter></term>
<listitem>
<para>
the number of substreams for playback
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>capture_count</parameter></term>
<listitem>
<para>
the number of substreams for capture
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rpcm</parameter></term>
<listitem>
<para>
the pointer to store the new pcm instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new PCM instance.
</para><para>
The pcm operators have to be set afterwards to the new instance
via <function>snd_pcm_set_ops</function>.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<!-- sound/core/pcm_lib.c -->
<refentry id="API-snd-pcm-set-ops">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_set_ops</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_set_ops</refname>
<refpurpose>
set the PCM operators
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_pcm_set_ops </function></funcdef>
<paramdef>struct snd_pcm * <parameter>pcm</parameter></paramdef>
<paramdef>int <parameter>direction</parameter></paramdef>
<paramdef>struct snd_pcm_ops * <parameter>ops</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
the pcm instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>direction</parameter></term>
<listitem>
<para>
stream direction, SNDRV_PCM_STREAM_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>ops</parameter></term>
<listitem>
<para>
the operator table
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Sets the given PCM operators to the pcm instance.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-set-sync">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_set_sync</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_set_sync</refname>
<refpurpose>
set the PCM sync id
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_pcm_set_sync </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the pcm substream
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Sets the PCM sync identifier for the card.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-interval-refine">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_interval_refine</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_interval_refine</refname>
<refpurpose>
refine the interval value of configurator
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_interval_refine </function></funcdef>
<paramdef>struct snd_interval * <parameter>i</parameter></paramdef>
<paramdef>const struct snd_interval * <parameter>v</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>i</parameter></term>
<listitem>
<para>
the interval value to refine
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>v</parameter></term>
<listitem>
<para>
the interval value to refer to
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Refines the interval value with the reference value.
The interval is changed to the range satisfying both intervals.
The interval status (min, max, integer, etc.) are evaluated.
</para><para>
Returns non-zero if the value is changed, zero if not changed.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-interval-ratnum">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_interval_ratnum</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_interval_ratnum</refname>
<refpurpose>
refine the interval value
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_interval_ratnum </function></funcdef>
<paramdef>struct snd_interval * <parameter>i</parameter></paramdef>
<paramdef>unsigned int <parameter>rats_count</parameter></paramdef>
<paramdef>struct snd_ratnum * <parameter>rats</parameter></paramdef>
<paramdef>unsigned int * <parameter>nump</parameter></paramdef>
<paramdef>unsigned int * <parameter>denp</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>i</parameter></term>
<listitem>
<para>
interval to refine
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rats_count</parameter></term>
<listitem>
<para>
number of ratnum_t
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rats</parameter></term>
<listitem>
<para>
ratnum_t array
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>nump</parameter></term>
<listitem>
<para>
pointer to store the resultant numerator
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>denp</parameter></term>
<listitem>
<para>
pointer to store the resultant denominator
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns non-zero if the value is changed, zero if not changed.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-interval-list">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_interval_list</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_interval_list</refname>
<refpurpose>
refine the interval value from the list
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_interval_list </function></funcdef>
<paramdef>struct snd_interval * <parameter>i</parameter></paramdef>
<paramdef>unsigned int <parameter>count</parameter></paramdef>
<paramdef>unsigned int * <parameter>list</parameter></paramdef>
<paramdef>unsigned int <parameter>mask</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>i</parameter></term>
<listitem>
<para>
the interval value to refine
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
the number of elements in the list
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>list</parameter></term>
<listitem>
<para>
the value list
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>mask</parameter></term>
<listitem>
<para>
the bit-mask to evaluate
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Refines the interval value from the list.
When mask is non-zero, only the elements corresponding to bit 1 are
evaluated.
</para><para>
Returns non-zero if the value is changed, zero if not changed.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-rule-add">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_rule_add</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_rule_add</refname>
<refpurpose>
add the hw-constraint rule
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_rule_add </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>unsigned int <parameter>cond</parameter></paramdef>
<paramdef>int <parameter>var</parameter></paramdef>
<paramdef>snd_pcm_hw_rule_func_t <parameter>func</parameter></paramdef>
<paramdef>void * <parameter>private</parameter></paramdef>
<paramdef>int <parameter>dep</parameter></paramdef>
<paramdef> <parameter>...</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
the pcm runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition bits
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
the variable to evaluate
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>func</parameter></term>
<listitem>
<para>
the evaluation function
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>private</parameter></term>
<listitem>
<para>
the private data pointer passed to function
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dep</parameter></term>
<listitem>
<para>
the dependent variables
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>...</parameter></term>
<listitem>
<para>
variable arguments
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-integer">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_integer</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_integer</refname>
<refpurpose>
apply an integer constraint to an interval
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_integer </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
hw_params variable to apply the integer constraint
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Apply the constraint of integer to an interval parameter.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-minmax">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_minmax</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_minmax</refname>
<refpurpose>
apply a min/max range constraint to an interval
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_minmax </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>unsigned int <parameter>min</parameter></paramdef>
<paramdef>unsigned int <parameter>max</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
hw_params variable to apply the range
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>min</parameter></term>
<listitem>
<para>
the minimal value
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>max</parameter></term>
<listitem>
<para>
the maximal value
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Apply the min/max range constraint to an interval parameter.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-list">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_list</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_list</refname>
<refpurpose>
apply a list of constraints to a parameter
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_list </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>unsigned int <parameter>cond</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>struct snd_pcm_hw_constraint_list * <parameter>l</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition bits
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
hw_params variable to apply the list constraint
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>l</parameter></term>
<listitem>
<para>
list
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Apply the list of constraints to an interval parameter.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-ratnums">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_ratnums</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_ratnums</refname>
<refpurpose>
apply ratnums constraint to a parameter
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_ratnums </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>unsigned int <parameter>cond</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>struct snd_pcm_hw_constraint_ratnums * <parameter>r</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition bits
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
hw_params variable to apply the ratnums constraint
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>r</parameter></term>
<listitem>
<para>
struct snd_ratnums constriants
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-ratdens">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_ratdens</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_ratdens</refname>
<refpurpose>
apply ratdens constraint to a parameter
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_ratdens </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>unsigned int <parameter>cond</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>struct snd_pcm_hw_constraint_ratdens * <parameter>r</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition bits
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
hw_params variable to apply the ratdens constraint
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>r</parameter></term>
<listitem>
<para>
struct snd_ratdens constriants
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-msbits">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_msbits</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_msbits</refname>
<refpurpose>
add a hw constraint msbits rule
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_msbits </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>unsigned int <parameter>cond</parameter></paramdef>
<paramdef>unsigned int <parameter>width</parameter></paramdef>
<paramdef>unsigned int <parameter>msbits</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition bits
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>width</parameter></term>
<listitem>
<para>
sample bits width
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>msbits</parameter></term>
<listitem>
<para>
msbits width
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-step">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_step</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_step</refname>
<refpurpose>
add a hw constraint step rule
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_step </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>unsigned int <parameter>cond</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>unsigned long <parameter>step</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition bits
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
hw_params variable to apply the step constraint
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>step</parameter></term>
<listitem>
<para>
step size
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-constraint-pow2">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_constraint_pow2</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_constraint_pow2</refname>
<refpurpose>
add a hw constraint power-of-2 rule
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_constraint_pow2 </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
<paramdef>unsigned int <parameter>cond</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
PCM runtime instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition bits
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
hw_params variable to apply the power-of-2 constraint
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-param-value">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_param_value</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_param_value</refname>
<refpurpose>
return <parameter>params</parameter> field <parameter>var</parameter> value
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_param_value </function></funcdef>
<paramdef>const struct snd_pcm_hw_params * <parameter>params</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>int * <parameter>dir</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>params</parameter></term>
<listitem>
<para>
the hw_params instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
parameter to retrieve
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dir</parameter></term>
<listitem>
<para>
pointer to the direction (-1,0,1) or <constant>NULL</constant>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Return the value for field <parameter>var</parameter> if it's fixed in configuration space
defined by <parameter>params</parameter>. Return -<constant>EINVAL</constant> otherwise.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-param-first">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_param_first</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_param_first</refname>
<refpurpose>
refine config space and return minimum value
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_param_first </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>pcm</parameter></paramdef>
<paramdef>struct snd_pcm_hw_params * <parameter>params</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>int * <parameter>dir</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
PCM instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>params</parameter></term>
<listitem>
<para>
the hw_params instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
parameter to retrieve
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dir</parameter></term>
<listitem>
<para>
pointer to the direction (-1,0,1) or <constant>NULL</constant>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Inside configuration space defined by <parameter>params</parameter> remove from <parameter>var</parameter> all
values > minimum. Reduce configuration space accordingly.
Return the minimum.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-hw-param-last">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_hw_param_last</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_hw_param_last</refname>
<refpurpose>
refine config space and return maximum value
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_hw_param_last </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>pcm</parameter></paramdef>
<paramdef>struct snd_pcm_hw_params * <parameter>params</parameter></paramdef>
<paramdef>snd_pcm_hw_param_t <parameter>var</parameter></paramdef>
<paramdef>int * <parameter>dir</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
PCM instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>params</parameter></term>
<listitem>
<para>
the hw_params instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>var</parameter></term>
<listitem>
<para>
parameter to retrieve
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dir</parameter></term>
<listitem>
<para>
pointer to the direction (-1,0,1) or <constant>NULL</constant>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Inside configuration space defined by <parameter>params</parameter> remove from <parameter>var</parameter> all
values < maximum. Reduce configuration space accordingly.
Return the maximum.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-lib-ioctl">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_lib_ioctl</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_lib_ioctl</refname>
<refpurpose>
a generic PCM ioctl callback
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_lib_ioctl </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
<paramdef>unsigned int <parameter>cmd</parameter></paramdef>
<paramdef>void * <parameter>arg</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the pcm substream instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cmd</parameter></term>
<listitem>
<para>
ioctl command
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>arg</parameter></term>
<listitem>
<para>
ioctl argument
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Processes the generic ioctl commands for PCM.
Can be passed as the ioctl callback for PCM ops.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-period-elapsed">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_period_elapsed</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_period_elapsed</refname>
<refpurpose>
update the pcm status for the next period
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_pcm_period_elapsed </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the pcm substream instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
This function is called from the interrupt handler when the
PCM has processed the period size. It will update the current
pointer, wake up sleepers, etc.
</para><para>
Even if more than one periods have elapsed since the last call, you
have to call this only once.
</para>
</refsect1>
</refentry>
<!-- sound/core/pcm_native.c -->
<refentry id="API-snd-pcm-stop">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_stop</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_stop</refname>
<refpurpose>
try to stop all running streams in the substream group
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_stop </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
<paramdef>int <parameter>state</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the PCM substream instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>state</parameter></term>
<listitem>
<para>
PCM state after stopping the stream
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
The state of each stream is then changed to the given state unconditionally.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-suspend">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_suspend</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_suspend</refname>
<refpurpose>
trigger SUSPEND to all linked streams
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_suspend </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the PCM substream
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
After this call, all streams are changed to SUSPENDED state.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-suspend-all">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_suspend_all</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_suspend_all</refname>
<refpurpose>
trigger SUSPEND to all substreams in the given pcm
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_suspend_all </function></funcdef>
<paramdef>struct snd_pcm * <parameter>pcm</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
the PCM instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
After this call, all streams are changed to SUSPENDED state.
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>PCM Format Helpers</title>
<!-- sound/core/pcm_misc.c -->
<refentry id="API-snd-pcm-format-signed">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_signed</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_signed</refname>
<refpurpose>
Check the PCM format is signed linear
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_signed </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns 1 if the given PCM format is signed linear, 0 if unsigned
linear, and a negative error code for non-linear formats.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-unsigned">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_unsigned</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_unsigned</refname>
<refpurpose>
Check the PCM format is unsigned linear
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_unsigned </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns 1 if the given PCM format is unsigned linear, 0 if signed
linear, and a negative error code for non-linear formats.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-linear">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_linear</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_linear</refname>
<refpurpose>
Check the PCM format is linear
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_linear </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns 1 if the given PCM format is linear, 0 if not.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-little-endian">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_little_endian</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_little_endian</refname>
<refpurpose>
Check the PCM format is little-endian
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_little_endian </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns 1 if the given PCM format is little-endian, 0 if
big-endian, or a negative error code if endian not specified.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-big-endian">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_big_endian</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_big_endian</refname>
<refpurpose>
Check the PCM format is big-endian
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_big_endian </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns 1 if the given PCM format is big-endian, 0 if
little-endian, or a negative error code if endian not specified.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-width">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_width</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_width</refname>
<refpurpose>
return the bit-width of the format
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_width </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the bit-width of the format, or a negative error code
if unknown format.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-physical-width">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_physical_width</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_physical_width</refname>
<refpurpose>
return the physical bit-width of the format
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_physical_width </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the physical bit-width of the format, or a negative error code
if unknown format.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-size">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_size</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_size</refname>
<refpurpose>
return the byte size of samples on the given format
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>ssize_t <function>snd_pcm_format_size </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
<paramdef>size_t <parameter>samples</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>samples</parameter></term>
<listitem>
<para>
sampling rate
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the byte size of the given samples for the format, or a
negative error code if unknown format.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-silence-64">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_silence_64</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_silence_64</refname>
<refpurpose>
return the silent data in 8 bytes array
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>const unsigned char * <function>snd_pcm_format_silence_64 </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the format to check
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the format pattern to fill or NULL if error.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-format-set-silence">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_format_set_silence</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_format_set_silence</refname>
<refpurpose>
set the silence data on the buffer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_format_set_silence </function></funcdef>
<paramdef>snd_pcm_format_t <parameter>format</parameter></paramdef>
<paramdef>void * <parameter>data</parameter></paramdef>
<paramdef>unsigned int <parameter>samples</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
the PCM format
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>
the buffer pointer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>samples</parameter></term>
<listitem>
<para>
the number of samples to set silence
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Sets the silence data on the buffer for the given samples.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-limit-hw-rates">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_limit_hw_rates</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_limit_hw_rates</refname>
<refpurpose>
determine rate_min/rate_max fields
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_limit_hw_rates </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
the runtime instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Determines the rate_min and rate_max fields from the rates bits of
the given runtime->hw.
</para><para>
Returns zero if successful.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-rate-to-rate-bit">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_rate_to_rate_bit</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_rate_to_rate_bit</refname>
<refpurpose>
converts sample rate to SNDRV_PCM_RATE_xxx bit
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>unsigned int <function>snd_pcm_rate_to_rate_bit </function></funcdef>
<paramdef>unsigned int <parameter>rate</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>rate</parameter></term>
<listitem>
<para>
the sample rate to convert
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or
SNDRV_PCM_RATE_KNOT for an unknown rate.
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>PCM Memory Management</title>
<!-- sound/core/pcm_memory.c -->
<refentry id="API-snd-pcm-lib-preallocate-free-for-all">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_lib_preallocate_free_for_all</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_lib_preallocate_free_for_all</refname>
<refpurpose>
release all pre-allocated buffers on the pcm
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_lib_preallocate_free_for_all </function></funcdef>
<paramdef>struct snd_pcm * <parameter>pcm</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
the pcm instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Releases all the pre-allocated buffers on the given pcm.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-lib-preallocate-pages">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_lib_preallocate_pages</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_lib_preallocate_pages</refname>
<refpurpose>
pre-allocation for the given DMA type
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_lib_preallocate_pages </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>struct device * <parameter>data</parameter></paramdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
<paramdef>size_t <parameter>max</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the pcm substream instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
DMA type (SNDRV_DMA_TYPE_*)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>
DMA type dependant data
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the requested pre-allocation size in bytes
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>max</parameter></term>
<listitem>
<para>
the max. allowed pre-allocation size
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Do pre-allocation for the given DMA buffer type.
</para><para>
When substream->dma_buf_id is set, the function tries to look for
the reserved buffer, and the buffer is not freed but reserved at
destruction time. The dma_buf_id must be unique for all systems
(in the same DMA buffer type) e.g. using <function>snd_dma_pci_buf_id</function>.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-lib-preallocate-pages-for-all">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_lib_preallocate_pages_for_all</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_lib_preallocate_pages_for_all</refname>
<refpurpose>
pre-allocation for continous memory type (all substreams)
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_lib_preallocate_pages_for_all </function></funcdef>
<paramdef>struct snd_pcm * <parameter>pcm</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>void * <parameter>data</parameter></paramdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
<paramdef>size_t <parameter>max</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
the pcm instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
DMA type (SNDRV_DMA_TYPE_*)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>
DMA type dependant data
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the requested pre-allocation size in bytes
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>max</parameter></term>
<listitem>
<para>
the max. allowed pre-allocation size
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Do pre-allocation to all substreams of the given pcm for the
specified DMA type.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-sgbuf-ops-page">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_sgbuf_ops_page</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_sgbuf_ops_page</refname>
<refpurpose>
get the page struct at the given offset
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>struct page * <function>snd_pcm_sgbuf_ops_page </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
<paramdef>unsigned long <parameter>offset</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the pcm substream instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>offset</parameter></term>
<listitem>
<para>
the buffer offset
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the page struct at the given buffer offset.
Used as the page callback of PCM ops.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-lib-malloc-pages">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_lib_malloc_pages</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_lib_malloc_pages</refname>
<refpurpose>
allocate the DMA buffer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_lib_malloc_pages </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
<paramdef>size_t <parameter>size</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the substream to allocate the DMA buffer to
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the requested buffer size in bytes
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Allocates the DMA buffer on the BUS type given earlier to
<function>snd_pcm_lib_preallocate_xxx_pages</function>.
</para><para>
Returns 1 if the buffer is changed, 0 if not changed, or a negative
code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-pcm-lib-free-pages">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_pcm_lib_free_pages</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_pcm_lib_free_pages</refname>
<refpurpose>
release the allocated DMA buffer.
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_pcm_lib_free_pages </function></funcdef>
<paramdef>struct snd_pcm_substream * <parameter>substream</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the substream to release the DMA buffer
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Releases the DMA buffer allocated via <function>snd_pcm_lib_malloc_pages</function>.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
</sect1>
</chapter>
<chapter><title>Control/Mixer API</title>
<sect1><title>General Control Interface</title>
<!-- sound/core/control.c -->
<refentry id="API-snd-ctl-new1">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_new1</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_new1</refname>
<refpurpose>
create a control instance from the template
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>struct snd_kcontrol * <function>snd_ctl_new1 </function></funcdef>
<paramdef>const struct snd_kcontrol_new * <parameter>ncontrol</parameter></paramdef>
<paramdef>void * <parameter>private_data</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ncontrol</parameter></term>
<listitem>
<para>
the initialization record
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>private_data</parameter></term>
<listitem>
<para>
the private data to set
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Allocates a new struct snd_kcontrol instance and initialize from the given
template. When the access field of ncontrol is 0, it's assumed as
READWRITE access. When the count field is 0, it's assumes as one.
</para><para>
Returns the pointer of the newly generated instance, or NULL on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-free-one">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_free_one</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_free_one</refname>
<refpurpose>
release the control instance
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_ctl_free_one </function></funcdef>
<paramdef>struct snd_kcontrol * <parameter>kcontrol</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>kcontrol</parameter></term>
<listitem>
<para>
the control instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Releases the control instance created via <function>snd_ctl_new</function>
or <function>snd_ctl_new1</function>.
Don't call this after the control was added to the card.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-add">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_add</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_add</refname>
<refpurpose>
add the control instance to the card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ctl_add </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>struct snd_kcontrol * <parameter>kcontrol</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>kcontrol</parameter></term>
<listitem>
<para>
the control instance to add
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Adds the control instance created via <function>snd_ctl_new</function> or
<function>snd_ctl_new1</function> to the given card. Assigns also an unique
numid used for fast search.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para><para>
It frees automatically the control which cannot be added.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-remove">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_remove</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_remove</refname>
<refpurpose>
remove the control from the card and release it
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ctl_remove </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>struct snd_kcontrol * <parameter>kcontrol</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>kcontrol</parameter></term>
<listitem>
<para>
the control instance to remove
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Removes the control from the card and then releases the instance.
You don't need to call <function>snd_ctl_free_one</function>. You must be in
the write lock - down_write(<structname>card</structname>->controls_rwsem).
</para><para>
Returns 0 if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-remove-id">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_remove_id</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_remove_id</refname>
<refpurpose>
remove the control of the given id and release it
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ctl_remove_id </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>struct snd_ctl_elem_id * <parameter>id</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
the control id to remove
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Finds the control instance with the given id, removes it from the
card list and releases it.
</para><para>
Returns 0 if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-rename-id">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_rename_id</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_rename_id</refname>
<refpurpose>
replace the id of a control on the card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ctl_rename_id </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>struct snd_ctl_elem_id * <parameter>src_id</parameter></paramdef>
<paramdef>struct snd_ctl_elem_id * <parameter>dst_id</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>src_id</parameter></term>
<listitem>
<para>
the old id
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dst_id</parameter></term>
<listitem>
<para>
the new id
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Finds the control with the old id from the card, and replaces the
id with the new one.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-find-numid">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_find_numid</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_find_numid</refname>
<refpurpose>
find the control instance with the given number-id
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>struct snd_kcontrol * <function>snd_ctl_find_numid </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>unsigned int <parameter>numid</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>numid</parameter></term>
<listitem>
<para>
the number-id to search
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Finds the control instance with the given number-id from the card.
</para><para>
Returns the pointer of the instance if found, or NULL if not.
</para><para>
The caller must down card->controls_rwsem before calling this function
(if the race condition can happen).
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-find-id">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_find_id</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_find_id</refname>
<refpurpose>
find the control instance with the given id
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>struct snd_kcontrol * <function>snd_ctl_find_id </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>struct snd_ctl_elem_id * <parameter>id</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
the id to search
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Finds the control instance with the given id from the card.
</para><para>
Returns the pointer of the instance if found, or NULL if not.
</para><para>
The caller must down card->controls_rwsem before calling this function
(if the race condition can happen).
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>AC97 Codec API</title>
<!-- sound/pci/ac97/ac97_codec.c -->
<refentry id="API-snd-ac97-write">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_write</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_write</refname>
<refpurpose>
write a value on the given register
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_ac97_write </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>unsigned short <parameter>reg</parameter></paramdef>
<paramdef>unsigned short <parameter>value</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>reg</parameter></term>
<listitem>
<para>
the register to change
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<para>
the value to set
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Writes a value on the given register. This will invoke the write
callback directly after the register check.
This function doesn't change the register cache unlike
#<function>snd_ca97_write_cache</function>, so use this only when you don't want to
reflect the change to the suspend/resume state.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-read">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_read</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_read</refname>
<refpurpose>
read a value from the given register
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>unsigned short <function>snd_ac97_read </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>unsigned short <parameter>reg</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>reg</parameter></term>
<listitem>
<para>
the register to read
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Reads a value from the given register. This will invoke the read
callback directly after the register check.
</para><para>
Returns the read value.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-write-cache">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_write_cache</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_write_cache</refname>
<refpurpose>
write a value on the given register and update the cache
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_ac97_write_cache </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>unsigned short <parameter>reg</parameter></paramdef>
<paramdef>unsigned short <parameter>value</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>reg</parameter></term>
<listitem>
<para>
the register to change
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<para>
the value to set
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Writes a value on the given register and updates the register
cache. The cached values are used for the cached-read and the
suspend/resume.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-update">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_update</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_update</refname>
<refpurpose>
update the value on the given register
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_update </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>unsigned short <parameter>reg</parameter></paramdef>
<paramdef>unsigned short <parameter>value</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>reg</parameter></term>
<listitem>
<para>
the register to change
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<para>
the value to set
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Compares the value with the register cache and updates the value
only when the value is changed.
</para><para>
Returns 1 if the value is changed, 0 if no change, or a negative
code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-update-bits">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_update_bits</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_update_bits</refname>
<refpurpose>
update the bits on the given register
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_update_bits </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>unsigned short <parameter>reg</parameter></paramdef>
<paramdef>unsigned short <parameter>mask</parameter></paramdef>
<paramdef>unsigned short <parameter>value</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>reg</parameter></term>
<listitem>
<para>
the register to change
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>mask</parameter></term>
<listitem>
<para>
the bit-mask to change
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<para>
the value to set
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Updates the masked-bits on the given register only when the value
is changed.
</para><para>
Returns 1 if the bits are changed, 0 if no change, or a negative
code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-get-short-name">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_get_short_name</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_get_short_name</refname>
<refpurpose>
retrieve codec name
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>const char * <function>snd_ac97_get_short_name </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the codec instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the short identifying name of the codec.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-bus">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_bus</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_bus</refname>
<refpurpose>
create an AC97 bus component
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_bus </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>int <parameter>num</parameter></paramdef>
<paramdef>struct snd_ac97_bus_ops * <parameter>ops</parameter></paramdef>
<paramdef>void * <parameter>private_data</parameter></paramdef>
<paramdef>struct snd_ac97_bus ** <parameter>rbus</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>num</parameter></term>
<listitem>
<para>
the bus number
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>ops</parameter></term>
<listitem>
<para>
the bus callbacks table
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>private_data</parameter></term>
<listitem>
<para>
private data pointer for the new instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rbus</parameter></term>
<listitem>
<para>
the pointer to store the new AC97 bus instance.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates an AC97 bus component. An struct snd_ac97_bus instance is newly
allocated and initialized.
</para><para>
The ops table must include valid callbacks (at least read and
write). The other callbacks, wait and reset, are not mandatory.
</para><para>
The clock is set to 48000. If another clock is needed, set
(*rbus)->clock manually.
</para><para>
The AC97 bus instance is registered as a low-level device, so you don't
have to release it manually.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-mixer">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_mixer</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_mixer</refname>
<refpurpose>
create an Codec97 component
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_mixer </function></funcdef>
<paramdef>struct snd_ac97_bus * <parameter>bus</parameter></paramdef>
<paramdef>struct snd_ac97_template * <parameter>template</parameter></paramdef>
<paramdef>struct snd_ac97 ** <parameter>rac97</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>bus</parameter></term>
<listitem>
<para>
the AC97 bus which codec is attached to
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>template</parameter></term>
<listitem>
<para>
the template of ac97, including index, callbacks and
the private data.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rac97</parameter></term>
<listitem>
<para>
the pointer to store the new ac97 instance.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates an Codec97 component. An struct snd_ac97 instance is newly
allocated and initialized from the template. The codec
is then initialized by the standard procedure.
</para><para>
The template must include the codec number (num) and address (addr),
and the private data (private_data).
</para><para>
The ac97 instance is registered as a low-level device, so you don't
have to release it manually.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-update-power">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_update_power</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_update_power</refname>
<refpurpose>
update the powerdown register
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_update_power </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>int <parameter>reg</parameter></paramdef>
<paramdef>int <parameter>powerup</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the codec instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>reg</parameter></term>
<listitem>
<para>
the rate register, e.g. AC97_PCM_FRONT_DAC_RATE
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>powerup</parameter></term>
<listitem>
<para>
non-zero when power up the part
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Update the AC97 powerdown register bits of the given part.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-suspend">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_suspend</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_suspend</refname>
<refpurpose>
General suspend function for AC97 codec
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_ac97_suspend </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Suspends the codec, power down the chip.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-resume">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_resume</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_resume</refname>
<refpurpose>
General resume function for AC97 codec
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_ac97_resume </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Do the standard resume procedure, power up and restoring the
old register values.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-tune-hardware">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_tune_hardware</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_tune_hardware</refname>
<refpurpose>
tune up the hardware
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_tune_hardware </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>struct ac97_quirk * <parameter>quirk</parameter></paramdef>
<paramdef>const char * <parameter>override</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>quirk</parameter></term>
<listitem>
<para>
quirk list
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>override</parameter></term>
<listitem>
<para>
explicit quirk value (overrides the list if non-NULL)
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Do some workaround for each pci device, such as renaming of the
headphone (true line-out) control as <quote>Master</quote>.
The quirk-list must be terminated with a zero-filled entry.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<!-- sound/pci/ac97/ac97_pcm.c -->
<refentry id="API-snd-ac97-set-rate">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_set_rate</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_set_rate</refname>
<refpurpose>
change the rate of the given input/output.
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_set_rate </function></funcdef>
<paramdef>struct snd_ac97 * <parameter>ac97</parameter></paramdef>
<paramdef>int <parameter>reg</parameter></paramdef>
<paramdef>unsigned int <parameter>rate</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>ac97</parameter></term>
<listitem>
<para>
the ac97 instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>reg</parameter></term>
<listitem>
<para>
the register to change
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rate</parameter></term>
<listitem>
<para>
the sample rate to set
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Changes the rate of the given input/output on the codec.
If the codec doesn't support VAR, the rate must be 48000 (except
for SPDIF).
</para><para>
The valid registers are AC97_PMC_MIC_ADC_RATE,
AC97_PCM_FRONT_DAC_RATE, AC97_PCM_LR_ADC_RATE.
AC97_PCM_SURR_DAC_RATE and AC97_PCM_LFE_DAC_RATE are accepted
if the codec supports them.
AC97_SPDIF is accepted as a pseudo register to modify the SPDIF
status bits.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-pcm-assign">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_pcm_assign</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_pcm_assign</refname>
<refpurpose>
assign AC97 slots to given PCM streams
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_pcm_assign </function></funcdef>
<paramdef>struct snd_ac97_bus * <parameter>bus</parameter></paramdef>
<paramdef>unsigned short <parameter>pcms_count</parameter></paramdef>
<paramdef>const struct ac97_pcm * <parameter>pcms</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>bus</parameter></term>
<listitem>
<para>
the ac97 bus instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>pcms_count</parameter></term>
<listitem>
<para>
count of PCMs to be assigned
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>pcms</parameter></term>
<listitem>
<para>
PCMs to be assigned
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
It assigns available AC97 slots for given PCMs. If none or only
some slots are available, pcm->xxx.slots and pcm->xxx.rslots[] members
are reduced and might be zero.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-pcm-open">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_pcm_open</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_pcm_open</refname>
<refpurpose>
opens the given AC97 pcm
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_pcm_open </function></funcdef>
<paramdef>struct ac97_pcm * <parameter>pcm</parameter></paramdef>
<paramdef>unsigned int <parameter>rate</parameter></paramdef>
<paramdef>enum ac97_pcm_cfg <parameter>cfg</parameter></paramdef>
<paramdef>unsigned short <parameter>slots</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
the ac97 pcm instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rate</parameter></term>
<listitem>
<para>
rate in Hz, if codec does not support VRA, this value must be 48000Hz
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>cfg</parameter></term>
<listitem>
<para>
output stream characteristics
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>slots</parameter></term>
<listitem>
<para>
a subset of allocated slots (snd_ac97_pcm_assign) for this pcm
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
It locks the specified slots and sets the given rate to AC97 registers.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-pcm-close">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_pcm_close</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_pcm_close</refname>
<refpurpose>
closes the given AC97 pcm
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_pcm_close </function></funcdef>
<paramdef>struct ac97_pcm * <parameter>pcm</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>pcm</parameter></term>
<listitem>
<para>
the ac97 pcm instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
It frees the locked AC97 slots.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ac97-pcm-double-rate-rules">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ac97_pcm_double_rate_rules</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ac97_pcm_double_rate_rules</refname>
<refpurpose>
set double rate constraints
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ac97_pcm_double_rate_rules </function></funcdef>
<paramdef>struct snd_pcm_runtime * <parameter>runtime</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>runtime</parameter></term>
<listitem>
<para>
the runtime of the ac97 front playback pcm
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Installs the hardware constraint rules to prevent using double rates and
more than two channels at the same time.
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>Virtual Master Control API</title>
<!-- sound/core/vmaster.c -->
<refentry id="API-snd-ctl-make-virtual-master">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_make_virtual_master</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_make_virtual_master</refname>
<refpurpose>
Create a virtual master control
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>struct snd_kcontrol * <function>snd_ctl_make_virtual_master </function></funcdef>
<paramdef>char * <parameter>name</parameter></paramdef>
<paramdef>const unsigned int * <parameter>tlv</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>name</parameter></term>
<listitem>
<para>
name string of the control element to create
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>tlv</parameter></term>
<listitem>
<para>
optional TLV int array for dB information
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a virtual matster control with the given name string.
Returns the created control element, or NULL for errors (ENOMEM).
</para><para>
After creating a vmaster element, you can add the slave controls
via <function>snd_ctl_add_slave</function> or <function>snd_ctl_add_slave_uncached</function>.
</para><para>
The optional argument <parameter>tlv</parameter> can be used to specify the TLV information
for dB scale of the master control. It should be a single element
with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
#SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
</para>
</refsect1>
</refentry>
<!-- include/sound/control.h -->
<refentry id="API-snd-ctl-add-slave">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_add_slave</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_add_slave</refname>
<refpurpose>
Add a virtual slave control
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ctl_add_slave </function></funcdef>
<paramdef>struct snd_kcontrol * <parameter>master</parameter></paramdef>
<paramdef>struct snd_kcontrol * <parameter>slave</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>master</parameter></term>
<listitem>
<para>
vmaster element
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>slave</parameter></term>
<listitem>
<para>
slave element to add
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Add a virtual slave control to the given master element created via
<function>snd_ctl_create_virtual_master</function> beforehand.
Returns zero if successful or a negative error code.
</para><para>
All slaves must be the same type (returning the same information
via info callback). The fucntion doesn't check it, so it's your
responsibility.
</para><para>
Also, some additional limitations:
at most two channels,
logarithmic volume control (dB level) thus no linear volume,
master can only attenuate the volume without gain
</para>
</refsect1>
</refentry>
<refentry id="API-snd-ctl-add-slave-uncached">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_ctl_add_slave_uncached</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_ctl_add_slave_uncached</refname>
<refpurpose>
Add a virtual slave control
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_ctl_add_slave_uncached </function></funcdef>
<paramdef>struct snd_kcontrol * <parameter>master</parameter></paramdef>
<paramdef>struct snd_kcontrol * <parameter>slave</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>master</parameter></term>
<listitem>
<para>
vmaster element
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>slave</parameter></term>
<listitem>
<para>
slave element to add
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Add a virtual slave control to the given master.
Unlike <function>snd_ctl_add_slave</function>, the element added via this function
is supposed to have volatile values, and get callback is called
at each time quried from the master.
</para><para>
When the control peeks the hardware values directly and the value
can be changed by other means than the put callback of the element,
this function should be used to keep the value always up-to-date.
</para>
</refsect1>
</refentry>
</sect1>
</chapter>
<chapter><title>MIDI API</title>
<sect1><title>Raw MIDI API</title>
<!-- sound/core/rawmidi.c -->
<refentry id="API-snd-rawmidi-receive">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_rawmidi_receive</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_rawmidi_receive</refname>
<refpurpose>
receive the input data from the device
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_rawmidi_receive </function></funcdef>
<paramdef>struct snd_rawmidi_substream * <parameter>substream</parameter></paramdef>
<paramdef>const unsigned char * <parameter>buffer</parameter></paramdef>
<paramdef>int <parameter>count</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the rawmidi substream
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buffer</parameter></term>
<listitem>
<para>
the buffer pointer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
the data size to read
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Reads the data from the internal buffer.
</para><para>
Returns the size of read data, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-rawmidi-transmit-empty">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_rawmidi_transmit_empty</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_rawmidi_transmit_empty</refname>
<refpurpose>
check whether the output buffer is empty
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_rawmidi_transmit_empty </function></funcdef>
<paramdef>struct snd_rawmidi_substream * <parameter>substream</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the rawmidi substream
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns 1 if the internal output buffer is empty, 0 if not.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-rawmidi-transmit-peek">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_rawmidi_transmit_peek</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_rawmidi_transmit_peek</refname>
<refpurpose>
copy data from the internal buffer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_rawmidi_transmit_peek </function></funcdef>
<paramdef>struct snd_rawmidi_substream * <parameter>substream</parameter></paramdef>
<paramdef>unsigned char * <parameter>buffer</parameter></paramdef>
<paramdef>int <parameter>count</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the rawmidi substream
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buffer</parameter></term>
<listitem>
<para>
the buffer pointer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
data size to transfer
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Copies data from the internal output buffer to the given buffer.
</para><para>
Call this in the interrupt handler when the midi output is ready,
and call <function>snd_rawmidi_transmit_ack</function> after the transmission is
finished.
</para><para>
Returns the size of copied data, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-rawmidi-transmit-ack">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_rawmidi_transmit_ack</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_rawmidi_transmit_ack</refname>
<refpurpose>
acknowledge the transmission
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_rawmidi_transmit_ack </function></funcdef>
<paramdef>struct snd_rawmidi_substream * <parameter>substream</parameter></paramdef>
<paramdef>int <parameter>count</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the rawmidi substream
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
the tranferred count
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Advances the hardware pointer for the internal output buffer with
the given size and updates the condition.
Call after the transmission is finished.
</para><para>
Returns the advanced size if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-rawmidi-transmit">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_rawmidi_transmit</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_rawmidi_transmit</refname>
<refpurpose>
copy from the buffer to the device
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_rawmidi_transmit </function></funcdef>
<paramdef>struct snd_rawmidi_substream * <parameter>substream</parameter></paramdef>
<paramdef>unsigned char * <parameter>buffer</parameter></paramdef>
<paramdef>int <parameter>count</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>substream</parameter></term>
<listitem>
<para>
the rawmidi substream
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buffer</parameter></term>
<listitem>
<para>
the buffer pointer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>count</parameter></term>
<listitem>
<para>
the data size to transfer
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Copies data from the buffer to the device and advances the pointer.
</para><para>
Returns the copied size if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-rawmidi-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_rawmidi_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_rawmidi_new</refname>
<refpurpose>
create a rawmidi instance
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_rawmidi_new </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>char * <parameter>id</parameter></paramdef>
<paramdef>int <parameter>device</parameter></paramdef>
<paramdef>int <parameter>output_count</parameter></paramdef>
<paramdef>int <parameter>input_count</parameter></paramdef>
<paramdef>struct snd_rawmidi ** <parameter>rrawmidi</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
the id string
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device</parameter></term>
<listitem>
<para>
the device index
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>output_count</parameter></term>
<listitem>
<para>
the number of output streams
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>input_count</parameter></term>
<listitem>
<para>
the number of input streams
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rrawmidi</parameter></term>
<listitem>
<para>
the pointer to store the new rawmidi instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new rawmidi instance.
Use <function>snd_rawmidi_set_ops</function> to set the operators to the new instance.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-rawmidi-set-ops">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_rawmidi_set_ops</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_rawmidi_set_ops</refname>
<refpurpose>
set the rawmidi operators
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_rawmidi_set_ops </function></funcdef>
<paramdef>struct snd_rawmidi * <parameter>rmidi</parameter></paramdef>
<paramdef>int <parameter>stream</parameter></paramdef>
<paramdef>struct snd_rawmidi_ops * <parameter>ops</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>rmidi</parameter></term>
<listitem>
<para>
the rawmidi instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>stream</parameter></term>
<listitem>
<para>
the stream direction, SNDRV_RAWMIDI_STREAM_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>ops</parameter></term>
<listitem>
<para>
the operator table
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Sets the rawmidi operators for the given stream direction.
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>MPU401-UART API</title>
<!-- sound/drivers/mpu401/mpu401_uart.c -->
<refentry id="API-snd-mpu401-uart-interrupt">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_mpu401_uart_interrupt</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_mpu401_uart_interrupt</refname>
<refpurpose>
generic MPU401-UART interrupt handler
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>irqreturn_t <function>snd_mpu401_uart_interrupt </function></funcdef>
<paramdef>int <parameter>irq</parameter></paramdef>
<paramdef>void * <parameter>dev_id</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>irq</parameter></term>
<listitem>
<para>
the irq number
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dev_id</parameter></term>
<listitem>
<para>
mpu401 instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Processes the interrupt for MPU401-UART i/o.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-mpu401-uart-interrupt-tx">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_mpu401_uart_interrupt_tx</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_mpu401_uart_interrupt_tx</refname>
<refpurpose>
generic MPU401-UART transmit irq handler
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>irqreturn_t <function>snd_mpu401_uart_interrupt_tx </function></funcdef>
<paramdef>int <parameter>irq</parameter></paramdef>
<paramdef>void * <parameter>dev_id</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>irq</parameter></term>
<listitem>
<para>
the irq number
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dev_id</parameter></term>
<listitem>
<para>
mpu401 instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Processes the interrupt for MPU401-UART output.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-mpu401-uart-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_mpu401_uart_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_mpu401_uart_new</refname>
<refpurpose>
create an MPU401-UART instance
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_mpu401_uart_new </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>int <parameter>device</parameter></paramdef>
<paramdef>unsigned short <parameter>hardware</parameter></paramdef>
<paramdef>unsigned long <parameter>port</parameter></paramdef>
<paramdef>unsigned int <parameter>info_flags</parameter></paramdef>
<paramdef>int <parameter>irq</parameter></paramdef>
<paramdef>int <parameter>irq_flags</parameter></paramdef>
<paramdef>struct snd_rawmidi ** <parameter>rrawmidi</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device</parameter></term>
<listitem>
<para>
the device index, zero-based
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>hardware</parameter></term>
<listitem>
<para>
the hardware type, MPU401_HW_XXXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>port</parameter></term>
<listitem>
<para>
the base address of MPU401 port
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>info_flags</parameter></term>
<listitem>
<para>
bitflags MPU401_INFO_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>irq</parameter></term>
<listitem>
<para>
the irq number, -1 if no interrupt for mpu
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>irq_flags</parameter></term>
<listitem>
<para>
the irq request flags (SA_XXX), 0 if irq was already reserved.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rrawmidi</parameter></term>
<listitem>
<para>
the pointer to store the new rawmidi instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new MPU-401 instance.
</para><para>
Note that the rawmidi instance is returned on the rrawmidi argument,
not the mpu401 instance itself. To access to the mpu401 instance,
cast from rawmidi->private_data (with struct snd_mpu401 magic-cast).
</para><para>
Returns zero if successful, or a negative error code.
</para>
</refsect1>
</refentry>
</sect1>
</chapter>
<chapter><title>Proc Info API</title>
<sect1><title>Proc Info Interface</title>
<!-- sound/core/info.c -->
<refentry id="API-snd-iprintf">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_iprintf</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_iprintf</refname>
<refpurpose>
printf on the procfs buffer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_iprintf </function></funcdef>
<paramdef>struct snd_info_buffer * <parameter>buffer</parameter></paramdef>
<paramdef>const char * <parameter>fmt</parameter></paramdef>
<paramdef> <parameter>...</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>buffer</parameter></term>
<listitem>
<para>
the procfs buffer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>fmt</parameter></term>
<listitem>
<para>
the printf format
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>...</parameter></term>
<listitem>
<para>
variable arguments
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Outputs the string on the procfs buffer just like <function>printf</function>.
</para><para>
Returns the size of output string.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-info-get-line">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_info_get_line</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_info_get_line</refname>
<refpurpose>
read one line from the procfs buffer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_info_get_line </function></funcdef>
<paramdef>struct snd_info_buffer * <parameter>buffer</parameter></paramdef>
<paramdef>char * <parameter>line</parameter></paramdef>
<paramdef>int <parameter>len</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>buffer</parameter></term>
<listitem>
<para>
the procfs buffer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>line</parameter></term>
<listitem>
<para>
the buffer to store
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>len</parameter></term>
<listitem>
<para>
the max. buffer size - 1
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Reads one line from the buffer and stores the string.
</para><para>
Returns zero if successful, or 1 if error or EOF.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-info-get-str">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_info_get_str</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_info_get_str</refname>
<refpurpose>
parse a string token
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>const char * <function>snd_info_get_str </function></funcdef>
<paramdef>char * <parameter>dest</parameter></paramdef>
<paramdef>const char * <parameter>src</parameter></paramdef>
<paramdef>int <parameter>len</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dest</parameter></term>
<listitem>
<para>
the buffer to store the string token
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>src</parameter></term>
<listitem>
<para>
the original string
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>len</parameter></term>
<listitem>
<para>
the max. length of token - 1
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Parses the original string and copy a token to the given
string buffer.
</para><para>
Returns the updated pointer of the original string so that
it can be used for the next call.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-info-create-module-entry">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_info_create_module_entry</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_info_create_module_entry</refname>
<refpurpose>
create an info entry for the given module
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>struct snd_info_entry * <function>snd_info_create_module_entry </function></funcdef>
<paramdef>struct module * <parameter>module</parameter></paramdef>
<paramdef>const char * <parameter>name</parameter></paramdef>
<paramdef>struct snd_info_entry * <parameter>parent</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>module</parameter></term>
<listitem>
<para>
the module pointer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>name</parameter></term>
<listitem>
<para>
the file name
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>parent</parameter></term>
<listitem>
<para>
the parent directory
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new info entry and assigns it to the given module.
</para><para>
Returns the pointer of the new instance, or NULL on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-info-create-card-entry">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_info_create_card_entry</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_info_create_card_entry</refname>
<refpurpose>
create an info entry for the given card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>struct snd_info_entry * <function>snd_info_create_card_entry </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>const char * <parameter>name</parameter></paramdef>
<paramdef>struct snd_info_entry * <parameter>parent</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>name</parameter></term>
<listitem>
<para>
the file name
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>parent</parameter></term>
<listitem>
<para>
the parent directory
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new info entry and assigns it to the given card.
</para><para>
Returns the pointer of the new instance, or NULL on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-card-proc-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_card_proc_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_card_proc_new</refname>
<refpurpose>
create an info entry for the given card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_card_proc_new </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>const char * <parameter>name</parameter></paramdef>
<paramdef>struct snd_info_entry ** <parameter>entryp</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>name</parameter></term>
<listitem>
<para>
the file name
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>entryp</parameter></term>
<listitem>
<para>
the pointer to store the new info entry
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new info entry and assigns it to the given card.
Unlike <function>snd_info_create_card_entry</function>, this function registers the
info entry as an ALSA device component, so that it can be
unregistered/released without explicit call.
Also, you don't have to register this entry via <function>snd_info_register</function>,
since this will be registered by <function>snd_card_register</function> automatically.
</para><para>
The parent is assumed as card->proc_root.
</para><para>
For releasing this entry, use <function>snd_device_free</function> instead of
<function>snd_info_free_entry</function>.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-info-free-entry">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_info_free_entry</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_info_free_entry</refname>
<refpurpose>
release the info entry
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_info_free_entry </function></funcdef>
<paramdef>struct snd_info_entry * <parameter>entry</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>entry</parameter></term>
<listitem>
<para>
the info entry
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Releases the info entry. Don't call this after registered.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-info-register">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_info_register</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_info_register</refname>
<refpurpose>
register the info entry
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_info_register </function></funcdef>
<paramdef>struct snd_info_entry * <parameter>entry</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>entry</parameter></term>
<listitem>
<para>
the info entry
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Registers the proc info entry.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
</sect1>
</chapter>
<chapter><title>Miscellaneous Functions</title>
<sect1><title>Hardware-Dependent Devices API</title>
<!-- sound/core/hwdep.c -->
<refentry id="API-snd-hwdep-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_hwdep_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_hwdep_new</refname>
<refpurpose>
create a new hwdep instance
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_hwdep_new </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>char * <parameter>id</parameter></paramdef>
<paramdef>int <parameter>device</parameter></paramdef>
<paramdef>struct snd_hwdep ** <parameter>rhwdep</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
the id string
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>device</parameter></term>
<listitem>
<para>
the device index (zero-based)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>rhwdep</parameter></term>
<listitem>
<para>
the pointer to store the new hwdep instance
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new hwdep instance with the given index on the card.
The callbacks (hwdep->ops) must be set on the returned instance
after this call manually by the caller.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>Jack Abstraction Layer API</title>
<!-- sound/core/jack.c -->
<refentry id="API-snd-jack-new">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_jack_new</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_jack_new</refname>
<refpurpose>
Create a new jack
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_jack_new </function></funcdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>const char * <parameter>id</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>struct snd_jack ** <parameter>jjack</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
an identifying string for this jack
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
a bitmask of enum snd_jack_type values that can be detected by
this jack
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>jjack</parameter></term>
<listitem>
<para>
Used to provide the allocated jack object to the caller.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Creates a new jack object.
</para><para>
Returns zero if successful, or a negative error code on failure.
On success jjack will be initialised.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-jack-set-parent">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_jack_set_parent</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_jack_set_parent</refname>
<refpurpose>
Set the parent device for a jack
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_jack_set_parent </function></funcdef>
<paramdef>struct snd_jack * <parameter>jack</parameter></paramdef>
<paramdef>struct device * <parameter>parent</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>jack</parameter></term>
<listitem>
<para>
The jack to configure
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>parent</parameter></term>
<listitem>
<para>
The device to set as parent for the jack.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Set the parent for the jack input device in the device tree. This
function is only valid prior to registration of the jack. If no
parent is configured then the parent device will be the sound card.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-jack-report">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_jack_report</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_jack_report</refname>
<refpurpose>
Report the current status of a jack
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_jack_report </function></funcdef>
<paramdef>struct snd_jack * <parameter>jack</parameter></paramdef>
<paramdef>int <parameter>status</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>jack</parameter></term>
<listitem>
<para>
The jack to report status for
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>status</parameter></term>
<listitem>
<para>
The current status of the jack
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
</sect1>
<sect1><title>ISA DMA Helpers</title>
<!-- sound/core/isadma.c -->
<refentry id="API-snd-dma-program">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_program</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_program</refname>
<refpurpose>
program an ISA DMA transfer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_dma_program </function></funcdef>
<paramdef>unsigned long <parameter>dma</parameter></paramdef>
<paramdef>unsigned long <parameter>addr</parameter></paramdef>
<paramdef>unsigned int <parameter>size</parameter></paramdef>
<paramdef>unsigned short <parameter>mode</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dma</parameter></term>
<listitem>
<para>
the dma number
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>addr</parameter></term>
<listitem>
<para>
the physical address of the buffer
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the DMA transfer size
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>mode</parameter></term>
<listitem>
<para>
the DMA transfer mode, DMA_MODE_XXX
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Programs an ISA DMA transfer for the given buffer.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-dma-disable">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_disable</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_disable</refname>
<refpurpose>
stop the ISA DMA transfer
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>void <function>snd_dma_disable </function></funcdef>
<paramdef>unsigned long <parameter>dma</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dma</parameter></term>
<listitem>
<para>
the dma number
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Stops the ISA DMA transfer.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-dma-pointer">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_dma_pointer</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_dma_pointer</refname>
<refpurpose>
return the current pointer to DMA transfer buffer in bytes
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>unsigned int <function>snd_dma_pointer </function></funcdef>
<paramdef>unsigned long <parameter>dma</parameter></paramdef>
<paramdef>unsigned int <parameter>size</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>dma</parameter></term>
<listitem>
<para>
the dma number
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>
the dma transfer size
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Returns the current pointer in DMA tranfer buffer in bytes
</para>
</refsect1>
</refentry>
</sect1>
<sect1><title>Other Helper Macros</title>
<!-- include/sound/core.h -->
<refentry id="API-snd-register-device">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_register_device</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_register_device</refname>
<refpurpose>
Register the ALSA device file for the card
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef>int <function>snd_register_device </function></funcdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>struct snd_card * <parameter>card</parameter></paramdef>
<paramdef>int <parameter>dev</parameter></paramdef>
<paramdef>const struct file_operations * <parameter>f_ops</parameter></paramdef>
<paramdef>void * <parameter>private_data</parameter></paramdef>
<paramdef>const char * <parameter>name</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
<para>
the device type, SNDRV_DEVICE_TYPE_XXX
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>card</parameter></term>
<listitem>
<para>
the card instance
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dev</parameter></term>
<listitem>
<para>
the device index
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>f_ops</parameter></term>
<listitem>
<para>
the file operations
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>private_data</parameter></term>
<listitem>
<para>
user pointer for f_ops-><function>open</function>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>name</parameter></term>
<listitem>
<para>
the device file name
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Registers an ALSA device file for the given card.
The operators have to be set in reg parameter.
</para><para>
This function uses the card's device pointer to link to the
correct <structname>struct device</structname>.
</para><para>
Returns zero if successful, or a negative error code on failure.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-printk">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_printk</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_printk</refname>
<refpurpose>
printk wrapper
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef> <function>snd_printk </function></funcdef>
<paramdef> <parameter>fmt</parameter></paramdef>
<paramdef> <parameter>args...</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>fmt</parameter></term>
<listitem>
<para>
format string
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>args...</parameter></term>
<listitem>
<para>
variable arguments
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Works like <function>printk</function> but prints the file and the line of the caller
when configured with CONFIG_SND_VERBOSE_PRINTK.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-printd">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_printd</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_printd</refname>
<refpurpose>
debug printk
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef> <function>snd_printd </function></funcdef>
<paramdef> <parameter>fmt</parameter></paramdef>
<paramdef> <parameter>args...</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>fmt</parameter></term>
<listitem>
<para>
format string
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>args...</parameter></term>
<listitem>
<para>
variable arguments
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Works like <function>snd_printk</function> for debugging purposes.
Ignored when CONFIG_SND_DEBUG is not set.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-BUG">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_BUG</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_BUG</refname>
<refpurpose>
give a BUG warning message and stack trace
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef> <function>snd_BUG </function></funcdef>
<void/>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<para>
None
</para>
</refsect1>
<refsect1>
<title>Description</title>
<para>
</para><para>
Calls <function>WARN</function> if CONFIG_SND_DEBUG is set.
Ignored when CONFIG_SND_DEBUG is not set.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-BUG-ON">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_BUG_ON</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_BUG_ON</refname>
<refpurpose>
debugging check macro
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef> <function>snd_BUG_ON </function></funcdef>
<paramdef> <parameter>cond</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>cond</parameter></term>
<listitem>
<para>
condition to evaluate
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
When CONFIG_SND_DEBUG is set, this macro evaluates the given condition,
and call <function>WARN</function> and returns the value if it's non-zero.
</para><para>
When CONFIG_SND_DEBUG is not set, this just returns zero, and the given
condition is ignored.
</para>
</refsect1>
<refsect1>
<title>NOTE</title>
<para>
the argument won't be evaluated at all when CONFIG_SND_DEBUG=n.
Thus, don't put any statement that influences on the code behavior,
such as pre/post increment, to the argument of this macro.
If you want to evaluate and give a warning, use standard <function>WARN_ON</function>.
</para>
</refsect1>
</refentry>
<refentry id="API-snd-printdd">
<refentryinfo>
<title>LINUX</title>
<productname>Kernel Hackers Manual</productname>
<date>June 2011</date>
</refentryinfo>
<refmeta>
<refentrytitle><phrase>snd_printdd</phrase></refentrytitle>
<manvolnum>9</manvolnum>
<refmiscinfo class="version">2.6.32</refmiscinfo>
</refmeta>
<refnamediv>
<refname>snd_printdd</refname>
<refpurpose>
debug printk
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Synopsis</title>
<funcsynopsis><funcprototype>
<funcdef> <function>snd_printdd </function></funcdef>
<paramdef> <parameter>format</parameter></paramdef>
<paramdef> <parameter>args...</parameter></paramdef>
</funcprototype></funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>format</parameter></term>
<listitem>
<para>
format string
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>args...</parameter></term>
<listitem>
<para>
variable arguments
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>
Works like <function>snd_printk</function> for debugging purposes.
Ignored when CONFIG_SND_DEBUG_VERBOSE is not set.
</para>
</refsect1>
</refentry>
</sect1>
</chapter>
</book>
