I had been running the r600 drivers or at least trying to, using the git versions of the kernel (drm-next branch), mesa, libdrm and xf86-video-ati on my Fedora 11 machine. And I understand that when running this type of config that things are probably gonna crash.
So when I used this config with KMS/DRI2 enabled it annoyed, but did not surprise me when it crashed. However, to get a stable system I was able to add radeon.modeset=0 to the kernel command line and things just worked correctly. No crashes, fast XV all that stuff.
So I decided that I should upgrade to F12 for a couple of reasons.
1. The new GTK with client side windows was included and I have a feeling that could cause gnome-mplayer some pain
2. The r600 drivers were built in to everything
So after downloading 2.5GB of files and upgrading using preupgrade I rebooted the machine. The preupgrade process ran, but hard locked the machine a couple of times using everything default while the upgrade was running (I should have known then). I finally on the third try added radeon.modeset=0 to the kernel command line and the preupgrade finished. After that was done I ran yum and got the latest of everything else.
Then more pain started. The machine using the default of everything would boot up and let me login and promptly lock pretty much right as the desktop showed up and sometimes it would even lockup in GDM when the screen was shuffling around and sometimes I would get 10 mins before it would lock up. So back to the radeon.modeset=0 option. However, this disabled all acceleration. Firefox was dead slow and xv didn't work. Unacceptable. Tired playing around with it a bit more and was out of lock, all I got were lockups for my efforts.
Luckily my motherboard has the Intel G35 chip onboard so I have that as a backup video card. So out comes the ATI card and in goes the ADD2 DVI adapter that I use with my display. After that everything is pretty happy and no lockups and etracer has twice the framerate with the Intel card as with the ATI card (this should not be). Now I know this is all early stuff and I do expect the ATI card to work eventually. But to have snapshot 3 of Fedora out and to have these kinda lockups, well that kinda sucks.