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

[Takashi Iwai]

At Tue, 20 Nov 2012 07:54:10 +0100,
Tomas Pospisek wrote:
> 
> On Sat, 17 Nov 2012 11:53:49 +0100, Takashi Iwai wrote:
> > At Sat, 17 Nov 2012 01:48:47 +0100, Tomas Pospisek wrote:
> >
> >> On Fri, 16 Nov 2012 17:04:03 +0100, Takashi Iwai wrote:
> >> > At Fri, 16 Nov 2012 15:23:06 +0100, Tomas Pospisek wrote:
> >> >> 
> >> >> The kernel of the upcoming Debian release and some
> >> >> recent kernels of Ubuntu seem to be suffering from HDA
> >> >> running at full force upon wakeup and producing
> >> >> a lot of heat (keeping the fan spinning loudly).
> >> > 
> >> > What do you mean "wakeup"?
> >> 
> >> Waking up from suspend to RAM.
> > 
> > And does the same issue occur on hibernation, too?
> > Basically both S2RAM and S2DISK use the same suspend/resume path
> > regarding the sound driver, so the behavior should be consistent in
> > both cases.
> 
> s2disk doesn't work here / isn't configured properly so I can't tell
> ad hoc.
> 
> >> >  Which kernel are you using?
> >> 
> >> 3.2.0-4-amd64 from Debian wheezy:
> >>   http://packages.debian.org/wheezy/linux-image-3.2.0-4-amd64
> > 
> > OK, could you check the latest Linus tree (at least 3.7-rc5) whether
> > the problem is still present?  If it is, please keep using it for the
> > further testing instead of 3.2.0.  3.2.0 is way too old to debug
> > primarily.
> 
> I'm running 3.7.0-rc6 now, with configuration from the "original" Debian
> kernel, make oldconfig and all choices to default.
> 
> > Also, try the latest alsa-lib from git tree, too.  I thought David
> > provides some packages built from the latest repo?
> 
> I've found this repository by David:
> 
>   https://launchpad.net/~diwic/+archive/dkms
> 
> however it seems to be deprecated and points to this:
> 
>   https://code.launchpad.net/~ubuntu-audio-dev/+archive/alsa-dailyvvv
> 
> which however only contains "dkms-hda" packages. I'm not sure what
> those packages contain, or rather whether they contain the latest alsa
> and utils. It seems that they "only" contain an out of tree hda
> build, but I'm not sure.
> 
> I'll try to compile latest alsa "the Debian way" and see if that changes
> anything.
> 
> >> > Which codec and HD-audio controller chips?
> >> 
> >> Wrt codec - I don't know. Before suspending I am not playing any sound.
> > 
> > Well, I meant the audio codec chip, not the codec format :)
> > But in the text below, you showed a conexant codec.
> > 
> > Also, it's important to know what h/w vendor and model are.
> > I guess it's a Lenovo machine?
> 
> It's not Conexant. It's:
> 
>             100.0%                      Device         Audio codec hwC0D0:
> IDT
>             100.0%                      Device         Audio codec hwC0D3:
> Intel
> 
> Note that with Debian's 3.2.0-4-amd64 kernel only the IDT codec would show
> up
> on the top of powertop's list. Now there's the Intel codec as well.

OK, I've read a different line for other people's machine, then.

(BTW, you can just check /proc/asound/card0/codec#0 and codec#3 files
 for more detailed information about the codec.  powertop gives only
 digests.)

> >> And the
> >> system (say the desktop system or the bell in a terminal) isn't
> producing
> >> any sound either.
> > 
> > OK.
> > 
> >> Powertop says "Audio codec hwC0D0: IDT". Other People in the launchpad
> >> bugtracker seem to be reporting either "hwC0D0: IDT", "hwC0D0:
> Conexant"
> >> or
> >> "hwC0D1: Conexant". 
> >> 
> >>   https://bugs.launchpad.net/ubuntu/+source/linux/+bug/877560
> >> 
> >> Here's the chip:
> >> 
> >> Audio:
> >> 00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset
> >> Family High Definition Audio Controller (rev 05)
> >> 
> >> >  Please elaborate a bit more instead of a bug track URL.  This will
> >> >  save lots of time for other people.
> >> 
> >> Powertop v2.0 shows:
> >> in the Overview tab:
> >>                 Usage       Events/s    Category       Description
> >>             100.0%                      Device         Audio codec
> >>             hwC0D0:
> >> IDT
> > 
> > The usage in powertop doesn't mean what actually consuming the power
> > in 100%.  It's a completely different statistics from the CPU usage.
> > 
> > It shows that the sound driver hasn't gone into the power-saving
> > mode, a sort of partial suspend of the device.  It can happen by
> > various reasons: e.g. when your system doesn't set up the power_save
> > option properly, or your mixer setup blocks it.
> > 
> > First off, check the value in
> > /sys/module/snd_hda_intel/parameters/power_save.  If it shows 0, it
> > means the power-saving feature is turned off.  If it's a positive
> > value, it means the power-saving may be turned on after the specified
> > seconds after closing all usages of sound devices.
> 
> Upon boot the value is 0. I can set it to 1 and it stays 1 while running,
> however if I suspend to ram and resume, the value gets reset to 0 again.

This is the system setup issue.  It has nothing to do with the driver
itself.

So, what is the *real* problem with it?  Did you measure any real
power consumption with it?

If the usages is turned off after playing something, it is the feature
in your kernel version.  As mentioned, power_save option itself didn't
trigger the power-save mode but it's activated only after closing a
device.  This was improved with 3.7, so check with the 3.7 kernel.


thanks,

Takashi