Hi again,
I posted last week because I am getting lockups when portaudio calls snd_pcm_drain, and snd_pcm_rate_drain calls snd_pcm_wait on its slave.
Now that I've looked at this more, I'm seeing that it involves dmix, since a dmix plugin is behind the rate plugin.
The dmix code in alsa-lib is setting a xrun state because snd_pcm_mmap_playback_avail returns a large value.
snd_pcm_wait is then called on the slave of the rate pcm, which is a pcm with a type of SND_PCM_TYPE_ROUTE whose slave is the dmix, but the route pcm is returning a different value for snd_pcm_mmap_avail than the dmix pcm, so it is not triggering snd_pcm_wait to check for a xrun.
The following patch stops snd_pcm_wait from locking up for me, although I'm not sure if it is the best way of handling things:
--- src/pcm/pcm.c.orig 2007-09-12 05:20:32.000000000 -0400 +++ src/pcm/pcm.c 2007-09-19 19:52:10.000000000 -0400 @@ -2255,7 +2255,7 @@ */ int snd_pcm_wait(snd_pcm_t *pcm, int timeout) { - if (snd_pcm_mmap_avail(pcm) >= pcm->avail_min) { + if (snd_pcm_mmap_avail(pcm) >= pcm->avail_min || pcm->type == SND_PCM_TYPE_ROUTE) { /* check more precisely */ switch (snd_pcm_state(pcm)) { case SND_PCM_STATE_XRUN:
Thanks, -- Mike Gorse / AIM:linvortex / http://mgorse.freeshell.org --