[alsa-devel] EeePC 1005PE microphone is "stereo only", silent in mono

Takashi Iwai tiwai at suse.de
Tue Aug 2 21:23:46 CEST 2011

At Tue, 02 Aug 2011 15:18:18 -0400,
Pavel Roskin wrote:
> On 08/02/2011 03:58 AM, Takashi Iwai wrote:
> > Kailang at Realtek suggested that the verb above is only for ALC269vb,
> > but he found out another workaround (coef idx 7 bit 7).
> >
> > Could you try the patch below?
> It works!  However, I needed an extra change for the new code to be 
> executed.  Also, I needed to backport the patch to Linux 3.0 (it's 
> wireless-testing.git, but for the sound code, it's essentially Linux 3.0).
> This condition is not true on my system:
> if (board_config == ALC_MODEL_AUTO) {
>           alc_pick_fixup(codec, NULL, alc269_fixup_tbl, alc269_fixups);
>           alc_apply_fixup(codec, ALC_FIXUP_ACT_PRE_PROBE);
> }
> board_config is 4 (ALC269_DMIC).  So the condition needs to be removed 
> for the fixup to be applied.  I guess the fixup for EeePC 1005HA should 
> be called elsewhere.  I'm not using any module parameters.

OK, then just pass model=auto.  It may result in different mixer
elements, but mostly it should work.  (Actually it's helpful if you
can test the auto-parser.)

> I get nothing but noise on the sound-2.6/master branch.  It happens 
> regardless of whether I'm using one or two channels with arecord.

Does it happen no matter whether patched and/or model option value?

> I remember a few cases when I was able to record proper sound with 2 
> channels on the sound-2.6/master kernel.  But most of the time, I would 
> get that noise.  It looks like a separate regression.
> I could try to bisect it.  It's a big investment of time, considering 
> that the system has an Atom CPU, so I'd like to know if there is any 
> interest in that, or there is some patch lying around that would address 
> the noise problem.

Before starting bisecting, please give alsa-info.sh outputs on both
working and non-working kernels.  Then we can compare the visible
difference of register values (although coef stuff isn't exposed



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