[alsa-devel] A problem about two microphones

[Hui Wang]

On 07/06/2017 03:40 PM, Takashi Iwai wrote:
> On Thu, 06 Jul 2017 04:09:07 +0200,
> Hui Wang wrote:
>> Recently we met a problem, on a lenovo machine, it has two
>> microphones(one is microphone, the other is headset-mic), and both of
>> them are located in the front panel.
>>
>> When the driver assigns names for them (via the function
>> hda_get_autocfg_input_label()), they are assigned the same name "Mic"
>> since they have the same location. So there are two "Mic", but the
>> pulseaudio can't handle two "Mic", in the pulseaudio, it can only
>> handle multiple inputs/microphones with different names, like "Mic"
>> and "Front Mic". If two microphones have the same name, we can only
>> see one of them through pulseaudio.
>>
>> I don't know how to solve this problem, the simplest way to workaround
>> it I can figure out is to change one of the microphone's location, let
>> them have differnt location, then they have differnet names.
>> Pin Default 0x02a19040: [Jack] Mic at Ext Front
>> Changed to:
>> Pin Default 0x04a19040: [Jack] Mic at Ext Right
>>
>> Do you have any ideas to solve this problem?
> As you noticed, an easy fix would be to fake the front mic by
> adjusting the pin config.  It's more or less acceptable, IMO.
> It'd be OK by adding a proper comment explaining the situation.
>
> Another option would be to rename the kctls later as you like.
> If PA works no matter which string prefix is, it's also an acceptable
> workaround, but I guess this would be come bigger changes than the
> above although it achieves an almost same result.
>
> Or fix PA, it's a better one for kernel side ;)
OK, got it. Since there is only one machine having this problem, let us 
use the simplest way to workaround it. And I guess it is very rare that 
machines have multiple Front Mic or Rear Mic in reality. If we have more 
machines having this problem, let us start to try a general solution then.

Thanks,
Hui.

>
> thanks,
>
> Takashi
>