1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>struct snd_compr_ops</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="The ALSA Driver API"><link rel="up" href="ch06.html#idp1095078220" title="Compress Offload API"><link rel="prev" href="API-struct-snd-compr-stream.html" title="struct snd_compr_stream"><link rel="next" href="API-struct-snd-compr.html" title="struct snd_compr"></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">struct snd_compr_ops</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-struct-snd-compr-stream.html">Prev</a> </td><th width="60%" align="center">Compress Offload API</th><td width="20%" align="right"> <a accesskey="n" href="API-struct-snd-compr.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-struct-snd-compr-ops"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>struct snd_compr_ops — 2 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="programlisting"> 3struct snd_compr_ops { 4 int (* open) (struct snd_compr_stream *stream); 5 int (* free) (struct snd_compr_stream *stream); 6 int (* set_params) (struct snd_compr_stream *stream,struct snd_compr_params *params); 7 int (* get_params) (struct snd_compr_stream *stream,struct snd_codec *params); 8 int (* set_metadata) (struct snd_compr_stream *stream,struct snd_compr_metadata *metadata); 9 int (* get_metadata) (struct snd_compr_stream *stream,struct snd_compr_metadata *metadata); 10 int (* trigger) (struct snd_compr_stream *stream, int cmd); 11 int (* pointer) (struct snd_compr_stream *stream,struct snd_compr_tstamp *tstamp); 12 int (* copy) (struct snd_compr_stream *stream, char __user *buf,size_t count); 13 int (* mmap) (struct snd_compr_stream *stream,struct vm_area_struct *vma); 14 int (* ack) (struct snd_compr_stream *stream, size_t bytes); 15 int (* get_caps) (struct snd_compr_stream *stream,struct snd_compr_caps *caps); 16 int (* get_codec_caps) (struct snd_compr_stream *stream,struct snd_compr_codec_caps *codec); 17}; </pre></div><div class="refsect1"><a name="idp1095206316"></a><h2>Members</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term">open</span></dt><dd><p> 18 Open the compressed stream 19 This callback is mandatory and shall keep dsp ready to receive the stream 20 parameter 21 </p></dd><dt><span class="term">free</span></dt><dd><p> 22 Close the compressed stream, mandatory 23 </p></dd><dt><span class="term">set_params</span></dt><dd><p> 24 Sets the compressed stream parameters, mandatory 25 This can be called in during stream creation only to set codec params 26 and the stream properties 27 </p></dd><dt><span class="term">get_params</span></dt><dd><p> 28 retrieve the codec parameters, mandatory 29 </p></dd><dt><span class="term">set_metadata</span></dt><dd><p> 30 Set the metadata values for a stream 31 </p></dd><dt><span class="term">get_metadata</span></dt><dd><p> 32 retrieves the requested metadata values from stream 33 </p></dd><dt><span class="term">trigger</span></dt><dd><p> 34 Trigger operations like start, pause, resume, drain, stop. 35 This callback is mandatory 36 </p></dd><dt><span class="term">pointer</span></dt><dd><p> 37 Retrieve current h/w pointer information. Mandatory 38 </p></dd><dt><span class="term">copy</span></dt><dd><p> 39 Copy the compressed data to/from userspace, Optional 40 Can't be implemented if DSP supports mmap 41 </p></dd><dt><span class="term">mmap</span></dt><dd><p> 42 DSP mmap method to mmap DSP memory 43 </p></dd><dt><span class="term">ack</span></dt><dd><p> 44 Ack for DSP when data is written to audio buffer, Optional 45 Not valid if copy is implemented 46 </p></dd><dt><span class="term">get_caps</span></dt><dd><p> 47 Retrieve DSP capabilities, mandatory 48 </p></dd><dt><span class="term">get_codec_caps</span></dt><dd><p> 49 Retrieve capabilities for a specific codec, mandatory 50 </p></dd></dl></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-struct-snd-compr-stream.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch06.html#idp1095078220">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-struct-snd-compr.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">struct snd_compr_stream</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">struct snd_compr</span></td></tr></table></div></body></html> 51