[alsa-devel] Grey noise with HDA Intel PCH

[Takashi Iwai]

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.


Takashi