[alsa-devel] Strange findings about the microphone in SigmaTel STAC9221 A1

[Ivan N. Zlatev]

On 5/15/07, Takashi Iwai <tiwai at suse.de> wrote:
> If this is 100% reproducible, you'll see likely a difference in
> /proc/asound/card0/codec#* file between working and non-working
> states.  Could you attach codec files in both states?
>

I have to do 4 things to enable the microphone (a built-in one) as
follows (with diffs of codec between steps)

1) Turn on capture and mux on and set them on max

 Node 0x12 [Audio Selector] wcaps 0x30010d: Stereo Amp-Out
   Amp-Out caps: ofs=0x00, nsteps=0x04, stepsize=0x27, mute=0
-  Amp-Out vals:  [0x00 0x00]
+  Amp-Out vals:  [0x04 0x04]
   Connection: 7
      0x0e* 0x15 0x0f 0x0b 0x0c 0x0d 0x0a

 Node 0x17 [Audio Selector] wcaps 0x300903: Stereo Amp-In
   Amp-In caps: N/A
-  Amp-In vals:  [0x80 0x80]
+  Amp-In vals:  [0x0e 0x0e]
   Connection: 1
      0x12

2) Switch from Mic to Front Mic - no changes
3) Switch from Front Mic back to Mic

Node 0x12 [Audio Selector] wcaps 0x30010d: Stereo Amp-Out
   Amp-Out caps: ofs=0x00, nsteps=0x04, stepsize=0x27, mute=0
   Amp-Out vals:  [0x04 0x04]
   Connection: 7
-     0x0e* 0x15 0x0f 0x0b 0x0c 0x0d 0x0a
+     0x0e 0x15 0x0f 0x0b* 0x0c 0x0d 0x0a

4) Put Capture on minimum and the mic will start recording with dodgy quality.

Node 0x17 [Audio Selector] wcaps 0x300903: Stereo Amp-In
   Amp-In caps: N/A
-  Amp-In vals:  [0x0e 0x0e]
+  Amp-In vals:  [0x00 0x00]

On 5/15/07, Takashi Iwai <tiwai at suse.de> wrote:
> The quality problem is perhaps because of the wrong pin setting.
> It's set in Hi-Z without vref.  But it's a bit strange because
> stac92xx_get_vref() should return the proper vref value.  Could you
> check whether this really gets called and which value is returned,
> e.g. by adding printk() there?

It doesn't get called according to my tests.

I've also tested with Alsa HG, but I can no longer make the mic work
with the steps descrived, not to mention that with imac-intel model I
get no sound.

Regards.
-- 
Ivan N. Zlatev

Web: http://www.i-nZ.net
"It's all some kind of whacked out conspiracy."