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 --
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