kernel-packages team mailing list archive

[Jan Kouba <571770@xxxxxxxxxxxxxxxxxx>]

Hi,

I have been able to get around this bug on IBM T60/x1400 running Kubuntu
12.04, by using kwin_gles desktop manager instead of the default one
(kwin).

I had problems with sound slowing down and being very choppy when
desktop effects were enabled, or when playing full-screen flash videos.
I did not notice any problems with wifi. With kwin_gles I have
absolutely no sound issues with desktop effects enabled.

How to change the window manager see: 
http://weits.blogspot.cz/2012/02/kwin-gles-as-default-window-manager-in.html

I'm not X expert, so please take the following lines as my humble
opinion. I belive, that the workaround is caused by the fact, that
kwin_gles uses EGL for rendering, while kwin uses GLX. So maybe this bug
can be avoided on other distros and window managers by setting them to
use EGL instead of GLX.

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https://bugs.launchpad.net/bugs/571770

Title:
  Thread [hd-audio0] consuming excessive amounts of CPU, audio crackling

Status in linux package in Ubuntu:
  Confirmed

Bug description:
  Binary package hint: linux-image-2.6.32-22-generic

  Sometimes during audio playback, a kernel thread named "[hd-audio0]"
  will consume excessive amounts of CPU and cause  audio crackling. It
  seems to be more easily triggered when displaying video in fullscreen
  (or Rhythmbox visualizations) or dragging windows around while playing
  music, somehow relating it graphics operations (running default radeon
  driver with KMS and Compiz).

  This all started after moving from Ubuntu Karmic to Lucid (never had
  this problem before).

  Setting package to kernel, since it's probably alsa snd_hda_intel
  kernel module which is to blame.

  Ubuntu 10.04 x86, Intel Core Duo 2GHz, 3GB RAM, ATI X1400 Radeon Mobility graphics.
  Audio chip: Analog Devices AD1981 [HDA]

  WORKAROUND: Disabling radeon KMS makes all the audio crackling go
  away.

  Attaching:
  * Screenshot of top running over Rhythmbox w/fullscreen visualizations, showing [hd-audio0] consuming more CPU than everything else at the time (audio crackles).
  * Output of "lspci -vvnn"
  * Output of "dmesg"
  * Contents of /proc/interrupts
  * ALSA info, as provided by the alsa-info.sh script.

  Related to this: https://bugzilla.kernel.org/show_bug.cgi?id=14935 ???

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