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.