[regression] Regular "cracks" in HDMI sound during playback since backport to 6.1.y for 92afcc310038 ("ALSA: hda: Conditionally use snooping for AMD HDMI")

[regression] Regular "cracks" in HDMI sound during playback since backport to 6.1.y for 92afcc310038 ("ALSA: hda: Conditionally use snooping for AMD HDMI")

[Salvatore Bonaccorso]

Hi

In downstream Debian we got a report from  Eric Degenetais, in
https://bugs.debian.org/1081833 that after the update to the 6.1.106
based version, there were regular cracks in HDMI sound during
playback.

Eric was able to bisec the issue down to
92afcc310038ebe5d66c689bb0bf418f5451201c in the v6.1.y series which
got applied in 6.1.104.

Cf. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1081833#47

#regzbot introduced: 92afcc310038ebe5d66c689bb0bf418f5451201c
#regzbot link: https://bugs.debian.org/1081833

It should be noted that Eric as well tried more recent stable series
as well, in particular did test as well 6.10.6 based version back on
20th september, and the issue was reproducible there as well.

Is there anything else we can try to provide?

Regards,
Salvatore

Re: [regression] Regular "cracks" in HDMI sound during playback since backport to 6.1.y for 92afcc310038 ("ALSA: hda: Conditionally use snooping for AMD HDMI")

[Linux regression tracking (Thorsten Leemhuis)]

Hi! On 28.09.24 15:19, Salvatore Bonaccorso wrote:
> 
> In downstream Debian we got a report from  Eric Degenetais, in
> https://bugs.debian.org/1081833 that after the update to the 6.1.106
> based version, there were regular cracks in HDMI sound during
> playback.
> 
> Eric was able to bisec the issue down to
> 92afcc310038ebe5d66c689bb0bf418f5451201c in the v6.1.y series which
> got applied in 6.1.104.
> 
> Cf. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1081833#47
> 
> #regzbot introduced: 92afcc310038ebe5d66c689bb0bf418f5451201c
> #regzbot link: https://bugs.debian.org/1081833
> 
> It should be noted that Eric as well tried more recent stable series
> as well, in particular did test as well 6.10.6 based version back on
> 20th september, and the issue was reproducible there as well.
> 
> Is there anything else we can try to provide?

Just "the usual", which is not widely known, so allow me to explain.

Please in situations like this *always* try to test a recent mainline
kernel. Given the timing, it's best to test 6.12-rc1 once it out later
today.

That's because it's unclear if this is something the regular maintainers
or the stable team/the one that asked for the backport has to handle.
Some developers do not care, but often it's required, as otherwise
nobody will take a close look -- especially when it comes to longterm
kernels. That's because participation in stable/longterm maintenance is
entirely optional for mainline developers (e.g. the author of the
culprit). This page
https://linux-regtracking.leemhuis.info/post/frequent-reasons-why-linux-kernel-bug-reports-are-ignored/
has a few points that explain the problem in more detail.

HTH, Ciao, Thorsten

Re: [regression] Regular "cracks" in HDMI sound during playback since backport to 6.1.y for 92afcc310038 ("ALSA: hda: Conditionally use snooping for AMD HDMI")

[Takashi Iwai]

On Sat, 28 Sep 2024 15:19:49 +0200,
Salvatore Bonaccorso wrote:
> 
> Hi
> 
> In downstream Debian we got a report from  Eric Degenetais, in
> https://bugs.debian.org/1081833 that after the update to the 6.1.106
> based version, there were regular cracks in HDMI sound during
> playback.
> 
> Eric was able to bisec the issue down to
> 92afcc310038ebe5d66c689bb0bf418f5451201c in the v6.1.y series which
> got applied in 6.1.104.
> 
> Cf. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1081833#47
> 
> #regzbot introduced: 92afcc310038ebe5d66c689bb0bf418f5451201c
> #regzbot link: https://bugs.debian.org/1081833
> 
> It should be noted that Eric as well tried more recent stable series
> as well, in particular did test as well 6.10.6 based version back on
> 20th september, and the issue was reproducible there as well.
> 
> Is there anything else we can try to provide?

Could you check 6.12-rc1 kernel whether the problem still appears?
If yes, check with snd_hda_intel.snoop=0 boot option. 

I guess we should revert the patch in anyway; for 6.12, it's no longer
correct to check with get_dma_ops(), and if this causes a problem on
the older releases, the assumption isn't correct, either.


thanks,

Takashi

Re: [regression] Regular "cracks" in HDMI sound during playback since backport to 6.1.y for 92afcc310038 ("ALSA: hda: Conditionally use snooping for AMD HDMI")

[Takashi Iwai]

On Mon, 30 Sep 2024 12:36:36 +0200,
Takashi Iwai wrote:
> 
> On Sat, 28 Sep 2024 15:19:49 +0200,
> Salvatore Bonaccorso wrote:
> > 
> > Hi
> > 
> > In downstream Debian we got a report from  Eric Degenetais, in
> > https://bugs.debian.org/1081833 that after the update to the 6.1.106
> > based version, there were regular cracks in HDMI sound during
> > playback.
> > 
> > Eric was able to bisec the issue down to
> > 92afcc310038ebe5d66c689bb0bf418f5451201c in the v6.1.y series which
> > got applied in 6.1.104.
> > 
> > Cf. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1081833#47
> > 
> > #regzbot introduced: 92afcc310038ebe5d66c689bb0bf418f5451201c
> > #regzbot link: https://bugs.debian.org/1081833
> > 
> > It should be noted that Eric as well tried more recent stable series
> > as well, in particular did test as well 6.10.6 based version back on
> > 20th september, and the issue was reproducible there as well.
> > 
> > Is there anything else we can try to provide?
> 
> Could you check 6.12-rc1 kernel whether the problem still appears?
> If yes, check with snd_hda_intel.snoop=0 boot option. 
> 
> I guess we should revert the patch in anyway; for 6.12, it's no longer
> correct to check with get_dma_ops(), and if this causes a problem on
> the older releases, the assumption isn't correct, either.

I decided to revert the commit.  Will submit the patch now.


Takashi