Comment 22 for bug 413296

I upgraded the drivers using Iain's ppa. On first reboot, X failed to start (Xsplash never showed up, screen stayed blank for several minutes.) The keyboard was responsive, and I was able to get to a tty. I removed the dkms module, and edited dkms.conf to disable fall_back_on_mtrr_if_no_pat.patch. Built the dkms module, rebooted, and all was well.

Then, I removed the dkms module again, re-enabled fall_back_on_mtrr_if_no_pat.patch, rebuilt the dkms module, and rebooted. It is now working. So I guess fall_back_on_mtrr_if_no_pat.patch can be ruled out as the cause of the problem.