Comment 7 for bug 554835

The 855 chipset has been particularly troublesome after the recent -intel driver work. For the Lucid release we have turned off KMS support for this chipset, in the hopes of not triggering the serious stability issues you and others have found.

It would therefore be useful if you could test this with kernel-modesetting disabled. You can do this either by adding “i915.modeset=0” to the kernel boot options, on the same line after “quiet splash”, or by following https://wiki.ubuntu.com/X/KernelModeSetting

Alternatively, if you update to the most recent kernel (2.6.32-21.32) kms will be disabled by default.

If this is resolved by disabling kernel modesetting, then we can close this bug. Please comment whether or not disabling KMS makes this problem better, worse, or no different.