[alsa-devel] Realtek ACL892: audio gap ~ each 10 seconds? [SOLVED]

[Takashi Iwai]

[Re-added Cc to alsa-devel to let others following]

At Fri, 11 May 2012 10:37:44 -0300,
Dâniel Fraga wrote:
> 
> On Fri, 11 May 2012 09:43:48 +0200
> Takashi Iwai <tiwai at suse.de> wrote:
> 
> > Does it mean that you have no headphone, or does the machine have no
> > headphone jack?
> 
> 	The machine has a headphone jack, but I never use a headphone.
> 
> > That's why I'm asking to test.  Usually when such a noise occurs due
> > to the auto-mute feature, it's because the bogus unsolicited events
> > are fired up too much although no jack is plugged actually.  Thus
> > usually the auto-mute feature itself doesn't work in such a case
> > (either no hardware implementation or the hardware has its own
> >  switching mechanism.)
> 	
> 	I understand. Ok... so you want me to plug the headphone and
> test if the auto-mute works right? Ok, I did that and yes, it works
> fine as expected (the audio from speakers is automatically muted when a
> headphone is inserted).

Hm, so it's strange that the auto-mute causes a problem.

Could you check which unsolicited events are triggered on your
machine?  When you build your kernel with the tracing support
(CONFIG_TRACEPOINTS=y), you can enable the tracing via

  % echo 1 > /sys/kernel/debug/tracing/events/hda/hda_unsol_event/enable

then after some time, gather the result by checking 
/sys/kernel/debug/tracing/trace file.  The output is like below.

  % cat /sys/kernel/debug/tracing/trace
  # tracer: nop
  #
  # entries-in-buffer/entries-written: 4/4   #P:4
  #
  #                              _-----=> irqs-off
  #                             / _----=> need-resched
  #                            | / _---=> hardirq/softirq
  #                            || / _--=> preempt-depth
  #                            ||| /     delay
  #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
  #              | |       |   ||||       |         |
            <idle>-0     [001] d.h3 10157.942108: hda_unsol_event: [0] res=10010020, res_ex=10
            <idle>-0     [001] d.h3 10158.848271: hda_unsol_event: [0] res=10010000, res_ex=10
  .....

Check whether the events come up frequently even without
plugging/unplugging any jacks.  Usually this shouldn't happen.  But in
the case of problematic hardware with the auto-mute, many bogus unsol
events are triggered.


thanks,

Takashi