Takashi Iwai wrote:
You can return SNDRV_PCM_POS_XRUN from the pointer callback (with kernel messages if you like). Then the PCM stream is stopped and the status is changed to SND_PCM_STATUS_XRUN. Further access will result in -EPIPE.
This doesn't seem to work. I don't get any more underrun/overrun messages, but the application doesn't know that something's failed.
With mplayer, I see this message:
alsa-lib: pcm_hw.c:405:(snd_pcm_hw_hwsync) SNDRV_PCM_IOCTL_HWSYNC failed: Broken pipe
And then mplayer hangs with the status bar here:
A: 0.0 (00.0) of 249.0 (04:09.0) ??,?% $<50>
aplay just hangs.
I also tried adding this code to my _pointer function:
snd_pcm_stream_lock_irqsave(substream, flags);
if (snd_pcm_running(substream)) snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
snd_pcm_stream_unlock_irqrestore(substream, flags);
but it didn't make any difference.