Comment 23 for bug 570011

Yet another update. It turns out that compositing proved not to be the culprit; things got bad faster if compositing was on, but eventually it happens anyway even if compositing was off. I was teaching recently and the display on my laptop was fine, but the display that the class saw was weaving in a slow samba dance. A bit embarassing. Had to reboot to fix it.

I now think the real culprit is kernel mode setting. I added a file /etc/modprobe.d/radeon.conf with the following line:
options radeon modeset=0

Since I added this, I have not seen wiggling displays. It is back to being a bit more like my previous experiences: I frequently have to restart X if I want the monitor to be recognized at its highest resolution. However, at least the display itself works, and the machine is more stable than with KMS on.