[pulseaudio-discuss] PA uses the card's output as input instead of microphone

[Nikos Chantziaras]

On 06/29/2010 12:02 AM, Tanu Kaskinen wrote:
> On Fri, 2010-06-25 at 12:42 +0300, Nikos Chantziaras wrote:
>> I've tried many combinations, but nothing works.  Here's what "Input
>> Devices" shows:
>>
>>     http://i46.tinypic.com/10ymnww.jpg
>>
>> The activity shown in the bottom bar is from an MP3 currently playing in
>> Amarok.  The microphone or line-in doesn't generate any kind of activity.
>>
>> Here's the "Recording" tab:
>>
>>     http://i46.tinypic.com/9h8j11.jpg
>>
>> Here too, the activity is generated by Amarok.  When selecting the other
>> choice in the shown pop-up menu, there's no activity shown, neither from
>> an MP3 nor from the microphone.
>
> Then the problem is that Pulseaudio isn't getting anything from the
> sound card's microphone input. The sound card seems to have multiple
> ports. What if you try to select some other port on the Input Devices
> tab?
>
> If changing the port doesn't help, then the next thing to try is to
> desperately flip random mixer switches using "alsamixer -c0". If that
> helps, please report back what elements needed changing (with luck we
> might be able to incorporate that information into the default
> configuration so that in the future your sound card would be supported
> better out-of-the-box).

I started tweaking everything at random.  After a while, the mic started 
to work.  In alsamixer, hitting F4 to get to the [Capture] settings, 
there's a setting called "Digital Source".  It was set to "AC97 in". 
The possible settings are:

   SRC out
   AC97 in
   i2s in
   IEC958 in
   i2s mixer out
   IEC958 out

I don't have the slightest idea of what that setting is for and what the 
choices mean, but the microphone only works when I set it to "i2s in". 
Every other settings results in the microphone being audible when 
increasing the "Capture feedback" volume no application can actually 
capture any sound from it.