<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>usb_autopm_put_interface</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The Linux-USB Host Side API" /><link rel="up" href="ch05.html" title="Chapter 5. USB Core APIs" /><link rel="prev" href="re81.html" title="usb_deregister" /><link rel="next" href="re83.html" title="usb_autopm_put_interface_async" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>usb_autopm_put_interface</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re81.html">Prev</a> </td><th width="60%" align="center">Chapter 5. USB Core APIs</th><td width="20%" align="right"> <a accesskey="n" href="re83.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="usb_autopm_put_interface"><a id="API-usb-autopm-put-interface"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_autopm_put_interface —
decrement a USB interface's PM-usage counter
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">usb_autopm_put_interface </b>(</code></td><td>struct usb_interface * <var class="pdparam">intf</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2750392"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>intf</code></em></span></dt><dd><p>
the usb_interface whose counter should be decremented
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2750419"></a><h2>Description</h2><p>
This routine should be called by an interface driver when it is
finished using <em class="parameter"><code>intf</code></em> and wants to allow it to autosuspend. A typical
example would be a character-device driver when its device file is
closed.
</p><p>
The routine decrements <em class="parameter"><code>intf</code></em>'s usage counter. When the counter reaches
0, a delayed autosuspend request for <em class="parameter"><code>intf</code></em>'s device is queued. When
the delay expires, if <em class="parameter"><code>intf</code></em>->pm_usage_cnt is still <= 0 along with all
the other usage counters for the sibling interfaces and <em class="parameter"><code>intf</code></em>'s
usb_device, the device and all its interfaces will be autosuspended.
</p><p>
Note that <em class="parameter"><code>intf</code></em>->pm_usage_cnt is owned by the interface driver. The
core will not change its value other than the increment and decrement
in usb_autopm_get_interface and usb_autopm_put_interface. The driver
may use this simple counter-oriented discipline or may set the value
any way it likes.
</p><p>
If the driver has set <em class="parameter"><code>intf</code></em>->needs_remote_wakeup then autosuspend will
take place only if the device's remote-wakeup facility is enabled.
</p><p>
Suspend method calls queued by this routine can arrive at any time
while <em class="parameter"><code>intf</code></em> is resumed and its usage counter is equal to 0. They are
not protected by the usb_device's lock but only by its pm_mutex.
Drivers must provide their own synchronization.
</p><p>
This routine can run only in process context.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re81.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch05.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re83.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>usb_deregister</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>usb_autopm_put_interface_async</span></td></tr></table></div></body></html>
