1<html><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 V1.78.1"><link rel="home" href="index.html" title="The Linux-USB Host Side API"><link rel="up" href="usbcore.html" title="Chapter&#160;5.&#160;USB Core APIs"><link rel="prev" href="API-usb-reset-configuration.html" title="usb_reset_configuration"><link rel="next" href="API-usb-register-dev.html" title="usb_register_dev"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">usb_driver_set_configuration</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-reset-configuration.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;5.&#160;USB Core APIs</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-usb-register-dev.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-usb-driver-set-configuration"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_driver_set_configuration &#8212; 
2     Provide a way for drivers to change device configurations
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><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>&#160;</td><td>int <var class="pdparam">config</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1116289404"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>udev</code></em></span></dt><dd><p>
4     the device whose configuration is being updated
5    </p></dd><dt><span class="term"><em class="parameter"><code>config</code></em></span></dt><dd><p>
6     the configuration being chosen.
7    </p></dd></dl></div></div><div class="refsect1"><a name="idp1116291996"></a><h2>Context</h2><p>
8   In process context, must be able to sleep
9</p></div><div class="refsect1"><a name="idp1116292628"></a><h2>Description</h2><p>
10   Device interface drivers are not allowed to change device configurations.
11   This is because changing configurations will destroy the interface the
12   driver is bound to and create new ones; it would be like a floppy-disk
13   driver telling the computer to replace the floppy-disk drive with a
14   tape drive!
15   </p><p>
16
17   Still, in certain specialized circumstances the need may arise.  This
18   routine gets around the normal restrictions by using a work thread to
19   submit the change-config request.
20</p></div><div class="refsect1"><a name="idp1116293844"></a><h2>Return</h2><p>
21   0 if the request was successfully queued, error code otherwise.
22   The caller has no way to know whether the queued request will eventually
23   succeed.
24</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-usb-reset-configuration.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="usbcore.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="API-usb-register-dev.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">usb_reset_configuration</span>&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;<span class="phrase">usb_register_dev</span></td></tr></table></div></body></html>
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