vt panic at startup, hd4650/hd6950

[Matt]

I've been seeing odd behavior with vt. At first I suspected my video 
hardware, hence the great delay.
I use slim to start X at boot. After a hard power off, or at random, my 
computer will boot twice or more times, panicking and rebooting when X loads. 
Trace is pretty quick, but I believe it's mostly supervisor read page not 
present. I recently got a different radeon, hd6950, and it still behaves 
similarly. Usually, the second boot is fine, but not always. Maybe 
uninitialized memory or something like that? Conflict between xf86-video-ati 
and vt? Does this sound familiar/known to anyone?

Matt