kernel-packages team mailing list archive

[Alexdeucher <571770@xxxxxxxxxxxxxxxxxx>]

(In reply to comment #76)
> @Alex Deucher: Yes, the modern operating systems and hardware are complex
> beasts and I surely understand that some bugs may be hard to track down. The
> point is however that there wasn't a systematic effort to resolve this
> particular issue except for some "there is a random problem X described in
> ticket Y, which may be the reason for your troubles too, so why don't you
> try the solution proposed there". By the way I tried the change proposed by
> Michel Dänzer in https://bugs.freedesktop.org/show_bug.cgi?id=38694 , but
> unfortunately it doesn't seem to help either.

There were several suggestions on this bug, but apparently none of them
helped.

> I am clueless about the kernel internals, but the manifestations of this bug
> seem to be consistent with the hypothesis that there is something wrong with
> the "radeon" driver. It seems like something locks the system for long
> periods of time and the other time sensitive modules "freak out". On my
> laptop the problem became even more pronounced when I swapped the "1440x900"
> LCD panel with a "1600x1200" one.

A bigger display means more data is being moved around.  It sounds to me
like a chipset issue when large amounts of data are being transferred
across the bus.  KMS uses system memory more readily than UMS did which
is likely why the issues shows up with KMS.  I don't know of any other
options to try in the driver.  We don't have these problems with the
same radeon chips is other systems.  Unfortunately, I'm not a chipset
expert so I'm not sure what sort of pci quirks, etc. to try.

It could also be that the there is an issue in the sound or wifi driver
which didn't show up as readily when there was less traffic on the bug.
As far as I know no one has investigated these avenues very much.

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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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