[alsa-devel] hda-intel and runtime power-management

[Tatulea, Dragos]

Hi,

I'm in the process of enabling pm runtime pm for the hda_intel driver,
not being sure if this is a sane task :). Noticed that
CONFIG_SND_HDA_POWER_SAVE disables codecs and chip when they are not
in use, but the power gain is not noticeable on my hw. On the other
hand, a full suspend (azx_suspend) does save a few hundred mW's.
I am aware that this is hw specific, but I would like to take
advantage of the full suspend. Suspend/resume latency is below jiffy
resolution.

How about a more aggressive scheme?: allow runtime power management
(with azx_suspend/resume as runtime pm ops) to kick in when all
streams are stopped/suspended/paused. And resume upon stream is
start/resume. I don't have enough context into ALSA & sound drivers so
I need a reality check: is this crazy/stupid?

Thanks,
Dragos