<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">Hi<br>
<br>
"time based scheduling" is enabled by default, my hardware is
ARM for automotive, maybe it is not suitable for<br>
the "time based scheduling", I wonder if I smaller the period
size would make the snd_pcm_avail more reliable.<br>
<br>
<br>
BR,<br>
Lixin<br>
<br>
在 2015年06月09日 13:02, Raymond Yau 写道:<br>
</div>
<blockquote
cite="mid:CAN8ccibd2aXx66ypAB-a3nu0KSk1N40rOCf22QbN3XN3tBkJLA@mail.gmail.com"
type="cite">
<p><br>
> <br>
> below is what the terminate shows when running
pcm_avail.c<br>
><br>
> uid=0 gid=1007@nutshell:/ #
alsactl_test <br>
> min_period_size: 8 frames, dir: 0<br>
> Playback hwparams: FIFO size is 8<br>
> Hardware PCM card 0 'rsnd-dai.0-dirana3.0' device 0
subdevice 0<br>
> Its setup is:<br>
> stream : PLAYBACK<br>
> access : RW_INTERLEAVED<br>
> format : S16_LE<br>
> subformat : STD<br>
> channels : 2<br>
> rate : 48000<br>
> exact rate : 48000 (48000/1)<br>
> msbits : 16<br>
> buffer_size : 4096<br>
> period_size : 1024<br>
> period_time : 21333<br>
> tstamp_mode : NONE<br>
> period_step : 1<br>
> avail_min : 1024<br>
> period_event : 0<br>
> start_threshold : 1024<br>
> stop_threshold : 4096<br>
> silence_threshold: 0<br>
> silence_size : 0<br>
> boundary : 1073741824<br>
> appl_ptr : 0<br>
> hw_ptr : 0<br>
> Playing silence<br>
> Available: 0, loop iteration: 0<br>
> Available: 1024, loop iteration: 1469<br>
> Available: 2048, loop iteration: 5609<br>
> Available: 3072, loop iteration: 9667<br>
><br>
> All I got is just the 4 lines.<br>
</p>
<p>If your sound card only increment hw_ptr only at interrupt
occur, you need to increase default_rewind_safeguard from 256
bytes to your selected period size<br>
</p>
<p>This mean that your sound card won't work with timer
scheduling or dynamic latency, you can only archieve low latency
by decrease period size <br>
Why do pulseaudio enable timer scheduling when most sound card
use IRQ ?</p>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
pulseaudio-discuss mailing list
<a class="moz-txt-link-abbreviated" href="mailto:pulseaudio-discuss@lists.freedesktop.org">pulseaudio-discuss@lists.freedesktop.org</a>
<a class="moz-txt-link-freetext" href="http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss">http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss</a>
</pre>
</blockquote>
<br>
</body>
</html>