[alsa-devel] Fwd: Re: Realtek ALC889: HDA Intel and kernel 3.1 gives choppy sound (again)

[Takashi Iwai]

At Mon, 19 Dec 2011 16:06:53 +0100,
David Henningsson wrote:
> 
> 2011-12-14 18:32, Takashi Iwai skrev:
> > At Wed, 14 Dec 2011 17:12:20 +0100,
> > Colomban Wendling wrote:
> >> Le 14/12/2011 15:48, Takashi Iwai a écrit :
> >>> At Wed, 14 Dec 2011 15:32:08 +0100,
> >>> Colomban Wendling wrote:
> >>>> Here's my initial mail, but with gzipped outputs.
> >>> Please don't drop Cc list.
> >> Sorry, I fwd'ed the message and forgot to update the CClist, sorry.
> >>
> >>>> Le 08/11/2011 07:32, Takashi Iwai a écrit :
> >>>>> At Mon, 07 Nov 2011 23:45:40 +0100,
> >>>>> Colomban Wendling wrote:
> >>>>>> Hi,
> >>>>>>
> >>>>>> Back to 3.0, the sound on my soundcard [1] started to be choppy, I
> >>>>>> reported it [2] and it got fixed (thanks to Takashi Iwai!).
> >>>>>>
> >>>>>> However, the story repeated with 3.1 (and probably 3.0.8 or before [3]):
> >>>>>> I've got similar choppy sound again.
> >>>>>>
> >>>>>> I bisected the few commits that happened on
> >>>>>> sound/pci/hda/patch_realtek.c, and finally found the villain:
> >>>>>>
> >>>>>> "8974bd51 ALSA: hda/realtek - Fix auto-mute with HP+LO configuration"
> >>>>>>
> >>>>>> Reverting it from v3.1 fixes the problem.
> >>>>> Does it?  Very weird.  This patch has nothing to do with the HD-audio
> >>>>> controller side but purely a codec change.
> >>>> Yep, I just check once again and it really fixes the problem here.
> >>>>
> >>>>>> master (94956ee) also suffers of the problem, but I couldn't test
> >>>>>> without that commit because reverting it fails, too much changes happened.
> >>>>> Did you try to pass position_fix=1 (or 2) option?
> >>>>> Also, passing enable_msi=0 (or 1) may change anything?
> >>>> I just tried with the 3 kernels:
> >>>>
> >>>> * vanilla v3.1
> >>>> * vanilla 3.2-rc1 (master at 1ea6b8f)
> >>>> * v3.1 with 8974bd51 reverted
> >>>>
> >>>> and none of the option changed anything: both vanilla always failed, the
> >>>> third always succeeded.  Though, I haven't combined the options, just
> >>>> tried each at once.
> >>>>
> >>>>> In anyway, please give alsa-info.sh output again with the fresh
> >>>>> kernel.  Run it with --no-upload option and attach the output.
> >>>> Here it is, for the 3 kernels cited above.
> >>> I see really no difference between vanilla3.1 and fixed.
> >>> The only difference is the NID 0x24, which is irrelevant with the
> >>> output.  It concludes that the commit you found has nothing to do with
> >>> the bug directly.  It's just a coincidence that it triggers
> >>> something.
> >>>
> >>> Which output are you testing?  Does the problem happen on both HP and
> >>> all line-outs?  Also, how are you testing?  How about the direct aplay
> >>> with -Dhw like
> >>> 	% aplay -Dhw foo.wav
> >>> ??
> >> Aha, you refined it!
> >>
> >> Even if I think it won't be really relevant any more (see below), what I
> >> did before was basically `mplayer -ao alsa<file>` and listening.  The
> >> first time I heard the problem I think I tried various players and
> >> output methods that all did suffer of the problem, so I don't really
> >> remember which ones.  Also, I (shame on me) ever only tested the rear
> >> line out.
> >>
> >> So then, the news:
> >>
> >> First, playing with aplay -Dhw (after fighting to get pulseaudio
> >> down...) doesn't change anything.
> >>
> >> But then, while all the rear outputs (L, SS, CS, RS) suffer of the
> >> choppiness, the front one never does!
> >> Moreover, if I plug something in the front output, sometimes [1] the
> >> rear ones doesn't mute and stop "choppying"  (I have correct sound in
> >> all outputs, rear and front).
> > Hm, then this can be really related with the jack-detection.
> > If so, the choppy sound is not because of the DMA position reporting
> > but because of the continuous triggering of jack-detect events.
> >
> > If you built your kernel with the tracepoint support, you'll have
> > /sys/kernel/debug/tracing/events/hda/enable file.  As root, run
> >
> >    # echo 1>  /sys/kernel/debug/tracing/events/hda/enable
> >
> > then check /sys/kernel/debu/tracing/trace file after some seconds.
> > Do you get any events there?  Also, what about plugging/unplugging the
> > headpohne jack?  After gathering the tracing info, disable again via:
> >
> >    # echo 0>  /sys/kernel/debug/tracing/events/hda/enable
> >
> > In anyway, if the jack-detection is really the problem, you can
> > disable the auto-mute feature by changing "Auto-Mute Mode" enum to
> > "Disabled".  Run "alsamixer -c0" and change the value.
> 
> Hmm, thanks for figuring this one out. Actually this is the third time I 
> hear of jack detection flipping back and forth. I'm wondering if we need 
> (and whether other OSes have?) a filter / flood protection on this 
> stuff, and if so, how it works? I mean, nobody would notice half a 
> second of delay on that switch anyway.

I don't think there is a perfect filtering for such a problem.
Theoretically we can see how often it's flipped, and disables the
jack-detection accordingly.  But not sure how useful it is in
practice, since it's a rare case, and the manual adjustment is easy.

BTW, maybe we should turn off the jack-detection while the auto-mute
is disabled?  Otherwise unsol events might still come up although they
are just ignored.


Takashi