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

Mark Brown broonie at sirena.org.uk
Mon Oct 27 21:44:41 CET 2008

On Thu, Oct 23, 2008 at 11:55:05PM +0100, Oliver Ford wrote:

> In terms of the control's direct effect, setting it in alsamixer gives:
> pxa2xx_ac97_write: 0c = af08

> setting it in amixer:
> pxa2xx_ac97_write: 0c = af09

On the one hand, that's odd.  On the other hand, the low bit of register
0xc is just a volume control for the right DAC so shouldn't make any
odds really.

> However, after running the offending amixer command this no longer 
> happens. It seems that the dapm_power_widgets() function determines that 
> the DAC is off and so doesn't power any widgets on at all.

Well, it determines that there's not a complete path so it doesn't
bother powering anything up which isn't *quite* the same thing.  It does
look like that's what's happening here - I can reproduce similar
behaviour here, though it's not quite the same system.  I'll try to fix
this tomorrow.

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