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

Pavel Roskin proski at gnu.org
Tue Aug 2 22:15:14 CEST 2011

On 08/02/2011 03:23 PM, Takashi Iwai wrote:

>> 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.)

That was it!  sound-2.6/master is working now.  No more noise.  Stereo 
and mono are fine.  No need to bisect anything.

So I just added "options snd_hda_intel model=auto" to /etc/modprobe.d

Obviously, it would be nice not to pass any parameters.  Things should 
just work.

>> 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?

The patch has no effect on the noise.  But model=auto makes all the 
difference.  And I wrongly assumed it was a default.

>> 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
> there).

I guess it's not needed anymore.  What's needed it to make "auto" the 
default (or some variation of that).

Pavel Roskin

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