1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>usb_autopm_get_interface</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-autopm-put-interface-no-suspend.html" title="usb_autopm_put_interface_no_suspend"><link rel="next" href="API-usb-autopm-get-interface-async.html" title="usb_autopm_get_interface_async"></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_autopm_get_interface</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-autopm-put-interface-no-suspend.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-autopm-get-interface-async.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-usb-autopm-get-interface"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_autopm_get_interface &#8212; 
2     increment a USB interface's PM-usage counter
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_autopm_get_interface </b>(</code></td><td>struct usb_interface * <var class="pdparam">intf</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1116430172"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>intf</code></em></span></dt><dd><p>
4     the usb_interface whose counter should be incremented
5    </p></dd></dl></div></div><div class="refsect1"><a name="idp1116431772"></a><h2>Description</h2><p>
6   This routine should be called by an interface driver when it wants to
7   use <em class="parameter"><code>intf</code></em> and needs to guarantee that it is not suspended.  In addition,
8   the routine prevents <em class="parameter"><code>intf</code></em> from being autosuspended subsequently.  (Note
9   that this will not prevent suspend events originating in the PM core.)
10   This prevention will persist until <code class="function">usb_autopm_put_interface</code> is called
11   or <em class="parameter"><code>intf</code></em> is unbound.  A typical example would be a character-device
12   driver when its device file is opened.
13   </p><p>
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15   <em class="parameter"><code>intf</code></em>'s usage counter is incremented to prevent subsequent autosuspends.
16   However if the autoresume fails then the counter is re-decremented.
17   </p><p>
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19   This routine can run only in process context.
20</p></div><div class="refsect1"><a name="idp1116434836"></a><h2>Return</h2><p>
21   0 on success.
22</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-autopm-put-interface-no-suspend.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-autopm-get-interface-async.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">usb_autopm_put_interface_no_suspend</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_autopm_get_interface_async</span></td></tr></table></div></body></html>
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