[alsa-devel] Strange control interactions on Tegra Harmony

Mark Brown broonie at opensource.wolfsonmicro.com
Thu Jan 27 19:49:28 CET 2011

On Thu, Jan 27, 2011 at 10:20:22AM -0800, Stephen Warren wrote:

> The Right Speaker Right Bypass control works the first and all subsequent
> times. Perhaps that's something to do with it being the last entry in
> wm8903.c's right_speaker_mixer[] array?

Possibly, though given the way DAPM processes those arrays I'd be a bit
surprised if it made a difference.  More likely to be that the bypass
paths is one of the simpler and more direct paths in the CODEC.

> I briefly started to debug this, and notice that the SND_SOC_DAPM_SPK event
> function isn't being called at all in the cases where muting doesn't toggle
> as expected.

I noticed something similar while developing a new driver the other day
but didn't get a chance to chase it down yet.  It's likely something got
confused, possibly with the recent changes to propagate DAPM state
between contexts, but that's just a guess as it's the most invasive
thing that happened there recently.

> Can you comment on this? I can certainly continue to debug it, but I figured
> it might be immediately obvious to you what the problem was e.g. if the same
> thing had happened on other platforms/codecs.

I'm on holiday tomorrow so can't have a proper look at live systems - if
you've not got anywhere by Monday I should be able to sort it then.

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