[alsa-devel] [PATCH] hda: Add dmux to STAC 9228

Matthew Ranostay mranostay at embeddedalley.com
Fri Oct 19 20:59:31 CEST 2007


Tim Gardner wrote:
> This doesn't seem to make a lot of difference. The external microphone
> is marginally better, but still not really usable (recognizable but
> distorted). The Gnome ALSA mixer shows 3 capture sources plus digital
> and 3 mux's. Only the first capture source records anything. I verified
> that you must have an external mic plugged in just to make sure the
> built-in mic wasn't recording.
>
> rtg
>
> Matthew Ranostay wrote:
>   
>> I think the problem is that I set the dmux to ADC1MUX instead of
>> ADC0MUX, could you test this patch to confirm?
>> Please let me know your results.
>>
>> Thanks,
>>
>> Matt Ranostay
>>
>>
>> ------------------------------------------------------------------------
>>
>> diff -r 7cf5e23f804e pci/hda/patch_sigmatel.c
>> --- a/pci/hda/patch_sigmatel.c	Fri Oct 19 08:23:00 2007 +0200
>> +++ b/pci/hda/patch_sigmatel.c	Fri Oct 19 13:47:35 2007 -0400
>> @@ -2777,7 +2777,7 @@ static int patch_stac927x(struct hda_cod
>>  	case 0x10280209: /* STAC 9228 */
>>  		spec->dmic_nids = stac927x_dmic_nids;
>>  		spec->num_dmics = STAC927X_NUM_DMICS;
>> -		spec->dmux_nid = 0x1c;
>> +		spec->dmux_nid = 0x1b;
>>  		break;
>>  	default:
>>  		spec->num_dmics = 0;	
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Alsa-devel mailing list
>> Alsa-devel at alsa-project.org
>> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>>     
>
>
>   
Ok it is true that there are 3 mux capture sources, but as of the moment 
we are only using one of them,
ADC0MUX(which will be the first capture source control).

The reason that you can barely hear any sound recording from a DMIC is 
that there is no hardware db gain, the
only way you can currently get measurable results is from software gain.

Hope that answers your questions.

Thanks,

Matt Ranostay


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