[alsa-devel] [PATCH 7/8] ALSA: pcm: Add card sync_irq field

[Ranjani Sridharan]

On Tue, 2019-11-19 at 09:24 +0100, Takashi Iwai wrote:
> On Tue, 19 Nov 2019 08:40:25 +0100,
> Ranjani Sridharan wrote:
> > 
> > > > 
> > > > Hi Takashi,
> > > > 
> > > > I just realized that In the SOF driver, we only set the
> > > > component
> > > > driver ops. The pcm ops are set when creating the new pcm. So,
> > > > should I
> > > > also add the sync_stop op in the component driver and set the
> > > > pcm
> > > > sync_stop op to point to the component sync_stop op? Just
> > > > wanted to
> > > > confirm if I am on the right track.
> > > 
> > > Yes, I didn't touch this yet, but that's the way to go I suppose.
> > > One caveat is that this ops is optional and needs NULL as
> > > default,
> > > hence you'd need to set only when defined, like copy_user, page
> > > or
> > > mmap ops, at least.
> > 
> > Hi Takashi,
> > 
> > This is what I tried in the SOF driver:
> > https://github.com/thesofproject/linux/pull/1513/commits
> > 
> > And it seems to cause the system to hang when I stop the stream and
> > I
> > have no meaningful logs to pinpoint to the problem. Could you
> > please
> > have a look at the 4 commits that I have added to your series and
> > let
> > me know what I could be missing? 
> 
> I couldn't find anything obvious.  Could you try without changing
> snd_sof_pcm_period_elapsed(), i.e. only adding the stuff and calling
> sync_stop, in order to see whether the additional stuff broke
> anything?
It is indeed the removal of snd_sof_pcm_period_elapsed() that makes the
device hang when the stream is stoppped. But that's a bit surprising
given that all I tried was using the snd_pcm_period_elapsed() directly
instead of scheduling the delayed work to call it.

Thanks,
Ranjani