Thanks for that report, it was just what I needed. I was already
tracking the various code responsible for updating posbuf and your trace
has confirmed some of what I was expecting. There are several reasons
why posbuf/pos won't be updated so we should try eliminating
possibilities.
In snd_pcm_update_hw_ptr_pos() it is possible that a buffer over-run
(XRUN) could prevent pos being updated:
pos = substream->ops->pointer(substream);
if (pos == SNDRV_PCM_POS_XRUN)
return pos; /* XRUN */
Because if the function didn't return at that point it would update pos:
pos -= pos % runtime->min_align;
Using CONFIG_SND_PCM_XRUN_DEBUG, in snd_pcm_update_hw_ptr_interrupt() we
might see something useful from:
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
if (runtime->periods > 1 && substream->pstr->xrun_debug) {
snd_printd(KERN_ERR "Unexpected hw_pointer value [1] (stream = %i, delta:
-%ld, max jitter = %ld): wrong interrupt acknowledge?\n", substream->stream,
(long) delta, runtime->buffer_size / 2);
if (substream->pstr->xrun_debug > 1)
dump_stack();
}
#endif
assuming that the function didn't return before it got to that point:
pos = snd_pcm_update_hw_ptr_pos(substream, runtime);
if (pos == SNDRV_PCM_POS_XRUN) {
xrun(substream);
return -EPIPE;
}
Alternatively, we need to watch snd_pcm_update_hw_ptr_interrupt() where
control can branch:
if (runtime->period_size == runtime->buffer_size)
goto __next_buf;
new_hw_ptr = runtime->hw_ptr_base + pos;
hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;
--
snd-hda-intel: distorted sound after resume, until the module is reloaded
https://bugs.launchpad.net/bugs/100114
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