[alsa-devel] SigmaTel STAC9221 - Mux Amp-Out > 0x02 == microphone not working

Takashi Iwai tiwai at suse.de
Tue May 29 17:29:10 CEST 2007

At Tue, 29 May 2007 16:20:33 +0100,
Ivan N. Zlatev wrote:
> On 5/29/07, Takashi Iwai <tiwai at suse.de> wrote:
> >
> > And, does this volume have any influence on the quality of recorded
> > sound at all?  If not, we should remove this control rather than
> > keeping a dangerous thing...
> >
> Yes. This controls the microphone boost level (without boost the sound
> recorded has *very* low volume). Also Windows shows  up a +20db
> microphone boost slider on this machine.

Ah, OK.  Then the control seems indicates the wrong max level indeed.
So, we need two fixes:

- rename "Mux Capture Volume" to more intuitive one, such as "Capture
  Boost" or something like that.

- limit the max level of this volume to 2.

The latter is a bit hard to fix.  Let's see whether I can do some



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