linux-kernel - Powersave doesn't work for snd_hda

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Message-ID: <20110610083956.GE4832@tiehlicka.suse.cz>
Date:	Fri, 10 Jun 2011 10:39:56 +0200
From:	Michal Hocko <mhocko@...e.cz>
To:	Takashi Iwai <tiwai@...e.de>
Cc:	LKML <linux-kernel@...r.kernel.org>, alsa-devel@...a-project.org
Subject: Powersave doesn't work for snd_hda_intel with 3.0.0-rc2

[changed subject]

As a summary:
I am loosing sound after powe_save timeout expires if there is no device
activity. The only way how to get sound back is to unload the module and
load it again.

On Fri 10-06-11 10:17:09, Takashi Iwai wrote:
> At Fri, 10 Jun 2011 09:56:40 +0200,
> Michal Hocko wrote:
> > > 
> > > Note that the one-minute thing happens only when you unplug AC cable,
> > > supposedly.  
> > 
> > Hmmm, I was plugged during testing all the time. OK, this looks like a
> > separate issue. I will repost it as a separate thread once we are done
> > with this. Any idea who to CC?
> 
> First off, check /sys/modules/snd_hda_intel/parameters/powersave
> value.  If this is set to non-zero, someone must have played with it,
> e.g. pm-utils or such.

Yes, it contains 60. And the value comes from:
CONFIG_SND_HDA_POWER_SAVE_DEFAULT=60

which defaults to 0 so it must have been changed by me some time ago
(really do not remember when and why, though). Anyway I have the same
value in 2.6.39 kernel as well and I do not see any problem there.
So it looks like a regression.

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic
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