FS#31255 - [linux] 3.5.2 Broken ALSA powersave

Attached to Project: Arch Linux
Opened by ValdikSS (ValdikSS) - Thursday, 23 August 2012, 06:22 GMT
Last edited by Tobias Powalowski (tpowa) - Monday, 15 October 2012, 10:07 GMT
Task Type Bug Report
Category Packages: Testing
Status Closed
Assigned To Tobias Powalowski (tpowa)
Thomas Bächler (brain0)
Architecture All
Severity Medium
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 2
Private No

Details

Description:
Audio codec is used 100% of time under some circumstances in 3.5.x. As for me, just start KDE and the codec won't suspend until reboot or laptop suspend. Here is a patch:
http://mailman.alsa-project.org/pipermail/alsa-devel/2012-August/054532.html (the latest one)
Everything is fine with 3.4.x.
This task depends upon

Closed by  Tobias Powalowski (tpowa)
Monday, 15 October 2012, 10:07 GMT
Reason for closing:  Fixed
Comment by John (graysky) - Thursday, 23 August 2012, 19:56 GMT
Can confirm through multiple user reports that this patch improves power consumption in linux-ck. Would be a good addition to the ARCH kernel. My understanding is that this fix will not be implemented until 3.6.0. Does anyone have a link official pull request?
Comment by Matthias Dienstbier (fs4000) - Thursday, 23 August 2012, 21:28 GMT
This is a bug obviously so it should get fixed in Linux 3.5.3.

http://git.kernel.org/?p=linux/kernel/git/tiwai/sound.git;a=commit;h=535b6c51fe8293c88ce919cdfc4390c67a1cb6d1
Comment by Tobias Powalowski (tpowa) - Saturday, 25 August 2012, 20:57 GMT
Will not be fixed before 3.5.4, 3.5.3 review began before the patch ws submitted.
Comment by Thomas Bächler (brain0) - Saturday, 25 August 2012, 23:22 GMT
Power consumption sometimes goes down when you start playing something and then stop. Doesn't always work though.

I think we can add the patch from alsa to our 3.5.3 build, Tobias?
Comment by skydrome (skydrome) - Wednesday, 12 September 2012, 13:46 GMT
  • Field changed: Percent Complete (100% → 0%)
patch applied to 3.5.3, still affects me.

00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02)

powetop:
Usage Device name
100.0% Audio codec alsa:hwC0D0: acer-aspire (Realtek)
Comment by Thomas Bächler (brain0) - Wednesday, 12 September 2012, 15:14 GMT
Okay, this is what I found: When you enable alsa powersave on boot, using the snd_hda_intel power_save=1 parameter, it works.

However, when you disable it and enable it again, it fails. Sometimes, using the audio device helps, sometimes it doesn't.

Unfortunately, the 'intel-audio-powersave' hook in pm-utils disables powersave everytime you go on AC and enables it again when you unplug. This triggers this bug. Blacklisting the 'intel-audio-powersave' hook in pm-utils has helped for me. It seems to cause cracks in the sound for some people, however, not for me.
Comment by Matthias Dienstbier (fs4000) - Wednesday, 12 September 2012, 16:26 GMT
Powersave should be retriggered after enabling the option and using the soundcard. Simply enabling powersave has never worked for me. Since I also have a stupid winmodem on the soundcard which can't be put into powersave at runtime I have put "options snd_hda_intel power_save=1" into /etc/modprobe.d/ and "INTEL_AUDIO_POWERSAVE=false" into /etc/pm/config.d/ to prevent pm-utils from changing this.
Comment by skydrome (skydrome) - Wednesday, 12 September 2012, 18:50 GMT
another thing i did was set CONFIG_SND_HDA_POWER_SAVE_DEFAULT to nonzero and it hasnt ever stayed at 100% usage in powertop anymore.

Update 9/18: kernel 3.5.4: modprobe.d/sound.conf options snd-hda-intel power_save=1 does not enable powersave nor does using snd_hda_intel either. Enabling powersave through powertop only takes effect if i plug a headphone jack in then take it out.
Comment by Greg (dolby) - Monday, 15 October 2012, 04:07 GMT
Status with latest kernels?
Comment by ValdikSS (ValdikSS) - Monday, 15 October 2012, 09:05 GMT
Everything is fine for me without patches.

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