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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>usb_driver_set_configuration</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="re71.html" title="usb_reset_configuration" /><link rel="next" href="re73.html" title="usb_register_dev" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>usb_driver_set_configuration</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re71.html">Prev</a> </td><th width="60%" align="center">Chapter 5. USB Core APIs</th><td width="20%" align="right"> <a accesskey="n" href="re73.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="usb_driver_set_configuration"><a id="API-usb-driver-set-configuration"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_driver_set_configuration —
Provide a way for drivers to change device configurations
</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">int <b class="fsfunc">usb_driver_set_configuration </b>(</code></td><td>struct usb_device * <var class="pdparam">udev</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">config</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2748754"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>udev</code></em></span></dt><dd><p>
the device whose configuration is being updated
</p></dd><dt><span class="term"><em class="parameter"><code>config</code></em></span></dt><dd><p>
the configuration being chosen.
</p></dd></dl></div></div><div class="refsect1" title="Context"><a id="id2748798"></a><h2>Context</h2><p>
In process context, must be able to sleep
</p></div><div class="refsect1" title="Description"><a id="id2748808"></a><h2>Description</h2><p>
Device interface drivers are not allowed to change device configurations.
This is because changing configurations will destroy the interface the
driver is bound to and create new ones; it would be like a floppy-disk
driver telling the computer to replace the floppy-disk drive with a
tape drive!
</p><p>
Still, in certain specialized circumstances the need may arise. This
routine gets around the normal restrictions by using a work thread to
submit the change-config request.
</p><p>
Returns 0 if the request was succesfully queued, error code otherwise.
The caller has no way to know whether the queued request will eventually
succeed.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re71.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="re73.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>usb_reset_configuration</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_register_dev</span></td></tr></table></div></body></html>
