> > 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. > > > I think that better fix is to change the code in snd_pcm_rate_drain(). You > can set avail_min to 1 there, so condition in snd_pcm_wait() will match. > > Does this patch help? > > diff -r 68d71239d651 src/pcm/pcm_rate.c > --- a/src/pcm/pcm_rate.c Thu Sep 20 13:20:03 2007 +0200 > +++ b/src/pcm/pcm_rate.c Fri Sep 21 10:14:41 2007 +0200 > @@ -1076,10 +1076,10 @@ static int snd_pcm_rate_drain(snd_pcm_t > snd_pcm_uframes_t size, ofs, saved_avail_min; > snd_pcm_sw_params_t sw_params; > > - /* temporarily set avail_min to one period */ > + /* temporarily set avail_min to one */ > sw_params = rate->sw_params; > saved_avail_min = sw_params.avail_min; > - sw_params.avail_min = rate->gen.slave->period_size; > + sw_params.avail_min = 1; > snd_pcm_sw_params(rate->gen.slave, &sw_params); > > size = rate->appl_ptr - rate->last_commit_ptr; > > Jaroslav Unfortunately, I just discovered that this patch (now in alsa-lib 1.0.15-rc3) does not always solve my problem. It does most of the time, but snd_pcm_avail on the route occasionally returns 0, which is less than 1, so once in a while I still get a lock-up. I can't change the 1 to a 0 in snd_pcm_drain since snd_pcm_sw_params aborts if sw_params->avail_min == 0. My original approach of checking for SND_PCM_TYPE_ROUTE in snd_pcm_wait() would still work. It looks as though there is a buffer to fill which is included when snd_pcm_mmap_avail looks at the dmix pcm but not when it looks at the route in between the rate and the dmix. -Mike G- _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
