On Sun, 7 Oct 2007, Jaroslav Kysela wrote: >>>> 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 we're looking bug on wrong place. If dmix is in XRUN state, > snd_pcm_poll_descriptors_revents() should return POLLERR, thus the check > for XRUN should be done in snd_pcm_wait_nocheck() after revents checking. > > Could you trace what occurs in your scenario in snd_pcm_wait_nocheck() ? Looking at the code suggests that snd_pcm_poll_descriptors_revents would return POLLERR if it ever got called, but it isn't called because poll() would have to return first, and it doesn't. Thanks, -Mike _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
