[g45] page flipping needs to be disabled (for now) on GM45 chipset

[Sergio Callegari]

Binary package hint: xserver-xorg-video-intel

On machines where lspci reports Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) and the xorg log a GM45 chipset, page flipping is broken with current DRM/xorg/intel drivers as well as with updated combinations of the above up to kernel 2.6.38, xorg 1.9, intel driver 2.14.

Sympthoms include severe display corruption whenever compositing is on and a full screen accelerated application is started and then stopped (screensaver, impress presentation, youtube full screen video, etc.). Under kde, sympthoms also include kwin crashes.

The bug is nasty, since recovery is possible only by disabling and re-enabling compositing, a non obvious operation, that the unexperienced user will not instinctively try, resorting to a reboot (with possible data loss).

Disabling page flipping makes xorg a bit slower but resolves the issue.

As long as the root cause of the problem is not identified and fixed, IMHO page-flipping should be disabled on this hardware.

See also https://bugs.freedesktop.org/show_bug.cgi?id=32303

[Roman (m01brv)]

I experience X hang-ups in KDE, occuring each time my screensaver (euphoria) is interrupted.
The KWin option "Suspend desktop effects for fullscreen windows" should be ticked on.
If this option is ticked off, no problem occures.

I looked in XOrg.0.log and found the following lines there:
[ 18468.582] (WW) intel(0): flip queue failed: Device or resource busy
[ 18468.582] (WW) intel(0): Page flip failed: Device or resource busy
and then X hang.

I have 82G33/G31 Express integrated Graphics Controller, therefore this video card dislikes page flipping too.
KUbuntu 11.04

[Sergio Callegari (callegar)]

Since the bug is still there in ubuntu natty, and ubuntu has shipped a new version of xorg 1.10.1-1ubuntu1.2, I am once more uploading on https://launchpad.net/~callegar/+archive/xorg an xorg package with page flipping disabled, hoping that this can be useful.

It is currently building.

Note that I am rarely getting the kwin crashes at the end of a full screen application even with suspend desktop effects for fullscreen windows.