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 6. 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> </td><th width="60%" align="center">Chapter 6. Host Controller APIs</th><td width="20%" align="right"> <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 — 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> </td><td>struct usb_host_endpoint ** <var class="pdparam">eps</var>, </td></tr><tr><td> </td><td>unsigned int <var class="pdparam">num_eps</var>, </td></tr><tr><td> </td><td>unsigned int <var class="pdparam">num_streams</var>, </td></tr><tr><td> </td><td>gfp_t <var class="pdparam">mem_flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </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. 20</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-hcd-giveback-urb.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="hcd.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-usb-free-streams.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">usb_hcd_giveback_urb</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span class="phrase">usb_free_streams</span></td></tr></table></div></body></html> 21