[PATCH] ASoC: Put LM4853 under DAPM control on GTA02
broonie at opensource.wolfsonmicro.com
Tue Mar 3 12:27:40 CET 2009
On Tue, Mar 03, 2009 at 11:08:35AM +0000, Andy Green wrote:
> This sounds great, but how does DAPM integrate with the analogue path
> usage which is the way we passthru audio for normal telephony? Last
> time I looked the ALSA side power management took a PCM-centric view of
> the world, it believes that PCM open was the sign we needed power some
> kind of "on" power state.
No, that's never been the case - ASoC has always handled full power path
management. If there is a complete path from a connected input to a
connected output then that path will be powered up - if this weren't the
case none of the paths in the codec would be powered for your bypass
paths so there would be nothing for the speaker to amplify.
The handling of the digital streams provides automatic power managment
for the DACs and ADCs so that their paths aren't powered when they
aren't in use.
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