[pulseaudio-discuss] Conexant CX20585 recording does not work

[David Henningsson]

On 2011-03-08 00:26, Colin Guthrie wrote:
> 'Twas brillig, and Gabriel Schulhof at 07/03/11 19:56 did gyre and gimble:
>> Hi!
>>
>> My mom has a laptop with the following sound card:
>>
>> lspci: 00:14.2 Audio device: ATI Technologies Inc SBx00 Azalia (Intel HDA)
>> (rev 40)
>>
>> driver: snd_hda_intel
>>
>> alsamixer:
>> Card: HDA ATI SB
>> Chip: Conexant CX20585
>>
>> I can't record from this card no matter what I try. It seems that
>> alsamixer has a lot more options than pulseaudio:
>>
>> Mic B<Capture switch>
>> Mic C<Capture switch>
>> Mic E<Capture switch>
>> Mic F<Capture switch>
>> Capture<0% -- 100% slider>
>> Analog Mic Boost<0 db -- 40 db slider with 10 db increment>
>>
>> Nevertheless, I will attach the output from pacmd list-sources.
>>
>> I have tried to record from each mic in turn, I have tried the different
>> boost levels (0 db - 40 db), but I have had no luck picking up anything. I
>> have attached an external mic to the line-in, but no difference.
>>
>> When I say "I have tried to record" I mean that I logged into her
>> computer, chose one of the mics from the above list, and then I told my
>> mom to say something while looking at the input sound level indicator in
>> the GNOME sound settings panel. On other computers, I have found this a
>> sufficient indication of whether the mic works.
>>
>> Is this inability to record a known limitation of this sound card? If not,
>> is there some special setting I have to modify to make it work?
>>
>> TIA for your help,
>
> Some mics do this weird out-of-phase thing whereby the recording level
> is effectively 0 when the stereo volume is synced. If you set left to
> say 5% and right to say 95% then it works fine.
>
> This may be the case with your h/w too.
>
> FWIW The "extra" options you see in ALSA are generally confusing and
> useless. PA attempts to consolidate it and make it a lot more user friendly.
>
> Normally you'd get a list of several "port" selectors in
> gnome-volume-control. Sadly as your card uses the incredibly helpful
> names of "Mic B" through "Mic F" these do not match the various
> "standard" names we probe for.
>
> David, have you come across this model on your travels?

Many times, that's the fallback for many Conexants.

> Any ideas on how
> we could best support it?

This one is one of few that lack an auto-parser of the pin default 
config, so for now - model quirks. Without seeing alsa-info or something 
similar, I can't tell which model would fit.

In the long run we would benefit from an autoparser handling these as well.

-- 
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic