1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>usb_alloc_streams</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="hcd.html" title="Chapter&#160;6.&#160;Host Controller APIs"><link rel="prev" href="API-usb-hcd-giveback-urb.html" title="usb_hcd_giveback_urb"><link rel="next" href="API-usb-free-streams.html" title="usb_free_streams"></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_alloc_streams</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-hcd-giveback-urb.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;6.&#160;Host Controller APIs</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-usb-free-streams.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-usb-alloc-streams"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_alloc_streams &#8212; 
2     allocate bulk endpoint stream IDs.
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_alloc_streams </b>(</code></td><td>struct usb_interface * <var class="pdparam">interface</var>, </td></tr><tr><td>&#160;</td><td>struct usb_host_endpoint ** <var class="pdparam">eps</var>, </td></tr><tr><td>&#160;</td><td>unsigned int <var class="pdparam">num_eps</var>, </td></tr><tr><td>&#160;</td><td>unsigned int <var class="pdparam">num_streams</var>, </td></tr><tr><td>&#160;</td><td>gfp_t <var class="pdparam">mem_flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1116774700"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>interface</code></em></span></dt><dd><p>
4     alternate setting that includes all endpoints.
5    </p></dd><dt><span class="term"><em class="parameter"><code>eps</code></em></span></dt><dd><p>
6     array of endpoints that need streams.
7    </p></dd><dt><span class="term"><em class="parameter"><code>num_eps</code></em></span></dt><dd><p>
8     number of endpoints in the array.
9    </p></dd><dt><span class="term"><em class="parameter"><code>num_streams</code></em></span></dt><dd><p>
10     number of streams to allocate.
11    </p></dd><dt><span class="term"><em class="parameter"><code>mem_flags</code></em></span></dt><dd><p>
12     flags hcd should use to allocate memory.
13    </p></dd></dl></div></div><div class="refsect1"><a name="idp1116780476"></a><h2>Description</h2><p>
14   Sets up a group of bulk endpoints to have <em class="parameter"><code>num_streams</code></em> stream IDs available.
15   Drivers may queue multiple transfers to different stream IDs, which may
16   complete in a different order than they were queued.
17</p></div><div class="refsect1"><a name="idp1116781628"></a><h2>Return</h2><p>
18   On success, the number of allocated streams. On failure, a negative
19   error code.
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