[alsa-devel] [PATCH 0/4] More aggressive PM for HD-audio

[Takashi Iwai]

At Fri, 20 Mar 2015 17:20:59 +0100,
David Henningsson wrote:
> 
> Anyhow, after reading through the code, I have a question about LEDs. It 
> could be that if vref is used for controlling a LED, maybe that pin 
> needs to stay in D0 for the LED to stay lit. Is this correctly handled? 
> I couldn't find any code specific to that issue, but maybe I just missed it.

Good point.  As far as I know, IDT codecs keep pinctl value no matter
whether the widget power state is.  So, it should be OK, judging only
from the spec.  But we need testing with the actual machine.  Maybe
it's really need a power up.

The VREF pins have to be constantly powered on, the fix shouldn't be
too difficult.

> Also, I find the power_mgmt name easy to confuse with the existing 
> power_save parameter, perhaps power_save_pin, power_save_node or 
> power_save_widget is better?

I don't mind renaming.  power_save_pin isn't appropriate because it's
not only about pins but all paths in general.  power_save_node might
sound generic enough.


thanks,

Takashi