X11 Freeze since upgrading to kernel 3.9

[Erwan David <erwan@rail.eu.org>]

	I use the radeon driver, SInce upgrading to kernel 3.9 I
regularly get X11 freeze, usually 20 to 30 s (those sevreal
time per hour) but about once a day it is a total X11 freeze.

ssh access to machine is still possible, but I need to reboot, and
even once I could not reboot with a kernel message saying that CPU3
was locked by the X process.

I am alone ? Is thios linked to
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1159414
?

Xhat is the solution ? (I hope it is not going to the proprietary
fglrx driver braindead for dual screen management).