RE: [PATCH] ASoC: da7219: Fix pole orientation detection on OMTP headsets when playing music

[David Rau]

-----Original Message-----
From: Guenter Roeck <groeck7@xxxxxxxxx> On Behalf Of Guenter Roeck
Sent: Saturday, February 4, 2023 23:42
To: Mark Brown <broonie@xxxxxxxxxx>
Cc: David Rau <david.rau.zg@xxxxxxxxxxx>; perex@xxxxxxxx; lgirdwood@xxxxxxxxx; tiwai@xxxxxxxx; support.opensource@xxxxxxxxxxx; alsa-devel@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] ASoC: da7219: Fix pole orientation detection on OMTP headsets when playing music

On Thu, Feb 02, 2023 at 07:36:42PM +0000, Mark Brown wrote:
> 
> > > they have the potential to actually lock up are the 
> > > cancel_work_sync() calls but they were unchanged and the backtrace 
> > > you showed was showing the thread in the msleep().  My guess would 
> > > be that you've got systems where there are very frequent jack 
> > > detection events (potentiallly with broken accessories, or 
> > > possibly due to the ground switch putting things into the wrong 
> > > priority) and that the interrupt is firing again as soon as the 
> > > thread unmasks the primary interrupt which means it never actually stops running.
> 
> > That is what I strongly suspect is happening. I don't know why 
> > exactly the interrupt is firing continuously, but the hang is always in msleep().
> > One possibility might be that the event is actually a disconnect 
> > event, and that enabling and immediately disabling the ground switch 
> > causes another interrupt, which is then handled immediately, causing the hang.
> 
> Could be.  I'd be willing to guess that it's not just one event but 
> rather a stream of events of some kind.  Possibly if it's due to the 
> ground switch it's spuriously detecting a constant stream of button 
> presses for the affected systems, which don't produce any UI visible 
> result which would cause users to pull the accessory for whatever 
> reason?  Whatever's going on I bet it's broken accessories triggering it.
> 

> That seems to be unlikely. The average number of crashes per affected system is 1.92, which points to something the users are doing and less to a broken accessory. 
> We do observe crashes due to broken accessories, but in those cases the number of crashes per system tends to be much > higher.

> Anyway, below is a patch with a possible fix. Of course, I still don't know what the patch originally tried to fix, so it might not do much if anything good.
I added the software debouncing before insertion task to ensue the better compatibility of OMTP Jack. 
> For example, it keeps button detection in the interrupt handler to avoid dropping button events, so if spurious button detection as you suspected is indeed (part of) the problem we might still see a large number of interrupts.

> Guenter

Thanks a lot for your big efforts to implement the temporary fix and verifications.
Would you please let me know the average number of crashes per affected system if you rollback to the pervious fix?
Ref:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/sound/soc/codecs?id=2d969e8f35b1849a43156029a7a6e2943b89d0c0
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/sound/soc/codecs?id=06f5882122e3faa183d76c4ec2c92f4c38e2c7bb

David
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