[alsa-devel] 100.0% power usage of Device Audio codec (HDA) on wake

David Henningsson david.henningsson at canonical.com
Tue Nov 20 09:56:19 CET 2012

On 11/20/2012 09:32 AM, Takashi Iwai wrote:
> At Tue, 20 Nov 2012 09:07:21 +0100,
> David Henningsson wrote:
>> It does put another question - from where does powertop get its values,
>> and do we have to do anything on our side to make sure / aid them being
>> correct?
> powertop checks /sys/class/sound/hwC*D*/power_{off|on}_acct files.
> They contain the time (in ms) how long the codec is in the power-save
> mode.

Thanks. But I have also recently seen a computer where powertop showed a 
Watt number, essentially saying that the codec consumed 1.4 Watts or so 
(I don't remember the exact number). Have you seen that too?

David Henningsson, Canonical Ltd.

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