Comment 45 for bug 194214

There's been some speculation here about this being a kernel issue. I don't think so, based on the testing I've done so far:

Latest hardy: Problem occurs
Latest hardy with gutsy kernel: Problem occurs
About one-month old hardy with gutsy kernel and gutsy xserver: I couldn't reproduce the problem.

If all else fails, this is how the problem can be isolated:
* Check that the issue is present in the latest upstream xserver git
* Check that it wasn't present in upstream xserver 1.3
* Do a git bisect

This is obviously a lengthy and painful process, but given the severity of the issue, it might be worth it. However, we should make sure that we get the opinion of an xorg developer first. Did anybody file an upstream bug report yet? Or has this been discussed on an xorg mailing list?