[alsa-devel] [RFC v2 0/3] ASoC: Option to reorder widget power sequence

[Mark Brown]

On Tue, Dec 07, 2010 at 11:29:15AM +0200, Peter Ujfalusi wrote:

> Fair enough.
> I did taken a look at the possibility to do the register update between DAPM 
> power down and up, but I thought it is a bit big change (the place, where the 
> DAPM power down and up happens is quite deep, and I was not sure how to inject 
> things between those).

Stash the callback in the DAPM context - we have to lock the context to
do the path walks anyway so no issue with reentrancy.

> If we do the update at the same time (or around), when the power for the 
> switch would have been enabled, than we are filtering the switching for the 
> DAPM widgets before the switch.

On the other hand it's possible that this will result in a sharp switch
in of a DC offset rather than a slow ramp, and anything doing DC offset
correction is going to want its input to be up before correcting.