[alsa-devel] Fix for Asus G75 notebook subwoofer

[Takashi Iwai]

At Wed, 07 Nov 2012 18:02:20 +0100,
Massimo Del Fedele wrote:
> 
> 
> Il 07/11/2012 16:54, Takashi Iwai ha scritto:
> >
> > It's OK, just missing the stereo capability check in the mixer code,
> > but almost harmless.  Which channel (left or right) of "surround"
> > mixer actually controls the volume of subwoofer on your machine?
> 
> Both, as the volume control is at DAC level and not at pin one.

OK, it must be because of the DAC amp being stereo.

> aplay with channel test sound shows a 4 channels audio, driving
> subwoofer with both rear left and rear right data.

Yes, this is still a missing piece.  The driver needs an override to
the standard chmap.

> If I lower left or right volume, just opposite channel goes to
> subwoofer.
> I guess that mono mixing is done at widget 0x3e (the hidden one).


Takashi