Comment 13 for bug 541492

On Thu, Apr 01, 2010 at 07:42:02AM -0000, Ivailo Stoyanov wrote:
> Unfortunately, after my previous optimistic report, I have experienced
> several random crashes (combined with wrong resolution signal to the
> monitor) similar to these reported by Jerry.

Jerry has reported some crashes as well as freezes. This bug report is
about a freeze rather than a crash.

If what you are seeing is a crash there will be a backtrace in your
Xorg.0.log (usually, or check gdm logs). Also be aware that the
backtraces in your Xorg.0.log are fairly useless - instead you need to
collect a full backtrace using either apport or gdb. See
http://wiki.ubuntu.com/X/Backtracing for details.

On the other hand, if you're seeing a freeze (graphics are frozen, but
maybe the mouse works) you need to follow the directions on
http://wiki.ubuntu.com/X/Troubleshooting/Freeze to collect data needed
for these kinds of issues.

However, I think it's pretty well known at this point that upstream's
code is fairly buggered with i845, so if you have that video card, if
you have a freeze it's probably not worth putting in more bug reports
about it at this point. You can track the upstream bug report as it
progresses, and help them with testing things. Be aware you'll probably
be expected to patch and build new kernels in order to do this.

Beyond that, assuming a patch doesn't come to light, the one other knob
we have to fiddle with at the distro level is to blacklist KMS from this
hardware. See http://wiki.ubuntu.com/X/KernelModeSetting for more info
about this and how to configure it off (basically boot i915.modeset=0)
so it uses UMS instead.

What we need is a convincing consensus among 845 owners that UMS works
better than KMS for the hardware, and then we can request the kernel
team to blacklist it.