[alsa-devel] Problem setting mixer switch with amixer/alsactl.

Mark Brown broonie at sirena.org.uk
Fri Oct 24 19:26:40 CEST 2008

On Thu, Oct 23, 2008 at 11:12:34PM +0100, Oliver Ford wrote:

> Am I right in understanding that setting all the controls in amixer  
> doesn't actually enable the control in the codec chip at that time but  
> that the powering on/off is done by soc-dapm.c when the the DAC is  
> actually enabled when playing some audio? This appears to be what is  
> happening when it does work (looking at the log). I hadn't realised this.

Sort of.  The power control happens whenever any power-related control
changes and whenever audio is started or stopped.

> I've put some debugging in pxa2xx-ac97-write and in dapm_power_widgets()  
> and the log is attached (stripped of non-audio stuff).

I'll have a look at these on Monday.

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