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

Andreas Kemnade andreas at kemnade.info
Mon Jun 10 10:59:05 CEST 2013


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
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. 

Greetings
Andreas Kemnade



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