Am Donnerstag, den 16.02.2012, 10:14 +0100 schrieb Paul Menzel:
> Am Mittwoch, den 15.02.2012, 01:38 -0800 schrieb j:
> > On 02/15/2012 01:31 AM, Paul Menzel wrote:
> > > Am Sonntag, den 12.02.2012, 00:22 +0100 schrieb Paul Menzel:
> > >> Am Freitag, den 10.02.2012, 06:08 -0800 schrieb Arjan van de Ven:
> > >>> On 2/10/2012 1:07 AM, Paul Menzel wrote:
> > >>>> Unfortunately neither `lsof` nor `fuser` returned any process using 
> > >>>> that
> > >>>> device.
> > >>>>
> > >>>>          $ sudo lsof /dev/snd/hwC0D0
> > >>>>          $ sudo fuser -v /dev/snd/hwC0D0
> > >>> also look for /dev/dsp or similar
> > >> That was also to no avail.
> > >>
> > >>>>>> or you found a real kernel driver bug ;-)
> > >>>> Looks like it. I guess I will contact the ALSA list and asking what 
> > >>>> this
> > >>>> device is about and if they can fix it.
> > >>>>
> > >>>> Could you answer a last question, please? What is PowerTOP actually
> > >>>> checking to figure out the usage.
> > >>> the codec's directory in sysfs (say
> > >>> /sys/devices/pci0000.00/0000:00:1b.0/sound/card0/hwC0D3) has 2 files,
> > >>> power_on_acct and power_off_act
> > >>> these count time that the codec is on or off respectively.
> > >>> powertop calculates a delta of these two over the measurement interval
> > >>> (20 seconds), and then since it knows how long it was on and off,
> > >>> calculates the percentage.
> > >> Thank you very much for that information. I brought that problem up to
> > >> the alsa-devel list [1].
> > > According to Takashi Iwai this is a known missing feature nobody has yet
> > > implemented. To get the power management enabled the audio device has to
> > > be opened by for example `echo -n | aplay`.
> > >
> > > Unfortunately I do not have any numbers how much "wasted" power we are
> > > talking about here.
> 
> > >> [1] 
> > >> http://mailman.alsa-project.org/pipermail/alsa-devel/2012-February/049019.html
> > > [2] 
> > > http://mailman.alsa-project.org/pipermail/alsa-devel/2012-February/049095.html
> 
> Am Mittwoch, den 15.02.2012, 01:36 -0800 schrieb j:
> > I see the same in my powertop2 results and have been searching for ways 
> > to cut it down as it seems to be the only thing really that while lists 
> > not actual wattage being drawn stays at a constant 100%. If there is any 
> > useful info I can pass along let me know.
> > 
> > Thanks for all the great work on the powertop project 
> 
> > Sorry forgot to post it says its Audio codec hwC0D0: Conextant. When not 
> > power saving (on ac) runs about 426mW 100% usage no results return with 
> > the listed commands requested before. When I apply my battery power 
> > savings nothing in mW but still stays at 100% usage
> 
> Please post the output of the `/sys/*` files I also posted.
> 
>         $
>         more /sys/module/snd_hda_intel/parameters/power_save_controller
>         $ more /sys/module/snd_hda_intel/parameters/power_save
> 
> And the following in the beginning with some pause in between.
> 
>         $ 
> /sys/devices/pci0000.00/0000:00:…/sound/card0/hwC0D0/power_{on,off}_acct
> 
> Then `echo -n | aplay` and the above again.
> 
>         $ 
> /sys/devices/pci0000.00/0000:00:…/sound/card0/hwC0D0/power_{on,off}_acct
> 
> Then `aplay some_wave_file.wav`.
> 
>         $ 
> /sys/devices/pci0000.00/0000:00:…/sound/card0/hwC0D0/power_{on,off}_acct
> 
> Then play some music using your favorite music player (MPlayer, Totem, …).
> 
>         $ 
> /sys/devices/pci0000.00/0000:00:…/sound/card0/hwC0D0/power_{on,off}_acct

j, did that work for you?

> PS: To keep threading, please also answer to your messages if you add
> something. If you do not get messages sent by you delivered to you again
> you can go to your sent folder and answer to the message their. Also
> please only send plain text messages which you already did in your later
> messages. [3] Thanks for that!


Thanks,

Paul


> [3] http://en.opensuse.org/openSUSE:Mailing_list_netiquette

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