[alsa-devel] [PATCH] various acer-mic-internal bugs solution

Maxim Levitsky maximlevitsky at gmail.com
Fri Aug 21 13:22:44 CEST 2009

On Wed, 2009-08-19 at 00:18 +0100, epic wrote:
> Several mic related bugs maybe solved with this patch or a derived one
>  1  -My internal-mic was not working and front jack mic sound was
> terrible (useless for headset mic).
>  2  -Detected offset level from inputs {line, mic}, this offset level
> increases with specific [boost] and/or [capture(NID 0x23)] gain.
> * I just played around several days compiling and testing alsa with my
> acer-alc268, checked all data communication with alc268, pin config etc.
> and tested different values for offset in pins.
> * Found internal-mic comes alive with a 50% offset v_reference and mic
> sound is much better.
> *This patch applies/solves only for alc268 with option model=acer in
> alsa-base.conf, but i think the others acer-alcxxx bugs maybe solved in
> the same way.
> 	changing PIN_VREF80 to PIN_VREF50 at
> 		NID 0x18 mic
> 		NID 0x19 internal-mic
> 		NID 0x1a line-in (not tested)
> *Don't know what can happen to other acer-alcxxx, so i only patched
> acer-alc268. But this patch solved my mic-internal issue and most
> important for me now i can use a headset mic.
> *It remains a level offset, lower than before, but mic is usable, the
> level is  showed in the pictures.

I have acer too (Aspire 5720)

And I also see high DC offsets on both internal and external mics
(and sound quality of internal mic is very bad)

But doesn't help here.
I have set the voltage on the corresonding pins using hda-verb, and I an
hardly notice any difference
(maybe the internal mic is already destroyed by high voltage...)

sudo ./hda-verb /dev/snd/hwC0D0 0x19 SET_PIN_WIDGET_CONTROL 0x21

(this one for internal mic)

Best regards,
	Maxim Levitsky

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