[alsa-devel] Grey noise with HDA Intel PCH

[Takashi Iwai]

At Thu, 14 Aug 2014 16:39:14 +0200,
Julian Wollrath wrote:
> 
> Am Thu, 14 Aug 2014 16:09:51 +0200
> schrieb Takashi Iwai <tiwai at suse.de>:
> 
> > At Thu, 14 Aug 2014 16:07:37 +0200,
> > Julian Wollrath wrote:
> > > 
> > > > > > > Simple mixer control 'Mic',0
> > > > > > >   Front Left: Playback 0 [0%] [-34.50dB] [on]
> > > > > > >   Front Right: Playback 0 [0%] [-34.50dB] [on]
> > > > > > 
> > > > > > This plays any noise from the mic input.
> > > > > Turning it off makes no difference since capture is turned off
> > > > > anyway:
> > > > 
> > > > This is a loopback mixer element, it has nothing to do with
> > > > capture stream.
> > > > 
> > > > The likely culprit of the static noises is the signal from the
> > > > analog loopback.  In some cases, you can disable the whole
> > > > loopback via "Loopback Mixing" mixer element on the fly.  In some
> > > > cases, you'd need to disable each mixer input (e.g. "Mic Playback
> > > > Switch"). In some cases (e.g. on some Sony and Dell laptops),
> > > > you'd need to disable the complete analog loopback at the
> > > > initialization.
> > > > 
> > > > The last one can be done via the early patching or sysfs
> > > > reconfiguration, pass "mixer_nid = 0" hint.  See HD-Audio.txt for
> > > > a brief instruction.
> > > Sadly, that did not help.
> > 
> > Give alsa-info.sh output after your change to verify whether you did
> > correctly.
> Here it is, cheers:

Thanks.  The setup looks OK, the path is:
  DAC (0x02) -> mixer (0x0c) -> mixer (0x14)
and the mixer mutes the loopback path (index 1).

Is it the state where you still hear the static noise?

Also, what if you use the module option for snd-hda-intel
model=nofixup or model=generic?


Takashi