[Gta04-owner] hw routing audio patch removed in 3.7?

[Dr. H. Nikolaus Schaller]

Am 10.06.2013 um 10:59 schrieb Andreas Kemnade:

> Hi,
> 
> On Mon, 2013-06-10 at 09:38 +0200, Dr. H. Nikolaus Schaller wrote: 
>> k, noise is back, i.e. more options to identify issues.
>> 
>> 1. it appears first when running the hw-test script.
>> 2. it does not appear with aplay -q /usr/share/sounds/alsa/Front_Center.wav
>> 3. but it appears with arecord | tee /tmp/echo.wav | aplay
>> 
>> While the command 3 is running there is intensive noise mixed into
>> the microphone signal. It works fine on a kernel without the patch.
>> 
>> AVADC gives:
>> 
>> root at gta04:~# amixer sget 'AVADC Clock Priority'                      
>> Simple mixer control 'AVADC Clock Priority',0
>>  Capabilities: enum
>>  Items: 'Voice high priority' 'HiFi high priority'
>>  Item0: 'Voice high priority'
>> root at gta04:~# 
>> 
>> After changing to HiFi priority the arecord | aplay works without noise.
>> Setting back to Voice high priority makes the noise come back.
>> 
> Just some background about that: The twl4030 has only one a/d converter
> for mic input and two digital clocks (Voice / Audio). The a/d converter
> can only run with one of them at a time. With that famous AVADC Clock

s/famous/infamous/ :)

> priority switch, you select which clock is used in case of conflicts. So
> properly setting that seems to be a must. If there is a clock mismatch
> (wrong setting of that switch, Hifi for Audio, Voice for direct gsm
> voice routing), we have a mess.
> 
>> So the question remains why it is not observed without the hw-routing
>> patch?
>> 
> Well the voice stuff is totally off then, so no need for setting
> priorities. 

Ah, I get it. Well we should document that somewhere...

Regarding the McBSP Tristate I have created this patch. It compiles
but I have no means to test it.

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