[alsa-devel] HD-audio runtime PM

David Henningsson david.henningsson at canonical.com
Mon Nov 25 10:20:55 CET 2013

On 11/25/2013 08:17 AM, Takashi Iwai wrote:
> At Mon, 25 Nov 2013 07:32:57 +0100,
> David Henningsson wrote:
>> On 11/22/2013 12:57 PM, Takashi Iwai wrote:
>>> Hi,
>>> after my previous fix, the runtime PM seems working stably finally.
>>> However, there seem still some glitches:
>>> 1. The wakeup via jack or HDMI/DP detection doesn't seem to work on my
>>>   test machines.  WAKEEN is set properly.  And its value can be read
>>>   correctly at the point of runtime resume, too.
>> Hi and thanks for working on this.
>> I've been trying to reproduce the above, but I can't seem to activate
>> runtime PM at all. I can't seem to get a callback to runtime_suspend,
>> and further investigation shows that
>> /sys/class/sound/card0/power/runtime_status shows "unsupported".
> You need to adjust power/control of the parent PCM device,
> i.e. /sys/devices/pci/*/power/control.  The following udev rule should
> work for HD-audio.  Give it a try.
>   ACTION=="add", SUBSYSTEM=="pci", ATTR{class}=="0x040300", TEST=="power/control", ATTR{power/control}="auto"

I tried this rule, but it did not make any difference -
/sys/class/sound/card0/device/power/control was still on. (And I did
proofread the rule...)

I tried "echo auto > /sys/class/sound/card0/device/power/control" -
after that, I had the following:

/sys/class/sound/card0/device/power/control - auto
/sys/class/sound/card0/device/power/runtime_status - active
/sys/class/sound/card0/power/control - auto
/sys/class/sound/card0/power/runtime_status - unsupported

...so it did not seem to help.

David Henningsson, Canonical Ltd.

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