[alsa-devel] [ALSA] ALSA Power Management, Drivers behaving unexpectedly after suspend/resume cycle

Liam Girdwood lg at opensource.wolfsonmicro.com
Fri May 25 11:09:28 CEST 2007

On Fri, 2007-05-25 at 11:27 +0530, Nobin Mathew wrote:
> I am implementing power management in my ALSA sound drivers. ALSA
> drivers are not working properly after resume. All registers values
> are proper and I am able to read back the codec register contents.

Iirc, you are using an AC97 codec. This means that the AC97 link is
running as expected after resume.

> If I do a playback after resume then I am getting lots of "underrun".

Do you hear any audio at all ? The underruns are probably being caused
by the AC97 Tx FIFO not being filled quickly enough by DMA. Is your DMA
being set up correctly after resume ?

> After a reboot playback is working fine.
> Is there any known issues with ALSA power  management?

ALSA suspend and resume works fine on lots of devices (all the ones I
have). I suspect you have a driver problem.


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