r300 PenumbraOverture complete hang 2.6.35/36-rc3 (regression)

[PJBrs]

Hello, I'm experiencing a hard lock (i.e., no magic SysRq) after playing 
PenumbraOverture for about a minute on my ThinkPad t43p with kernel 
2.6.35 / 2.6.36-rc3. I'm using KMS. 2.6.34 works fine. I didn't test 
thoroughly with 2.6.35. With 2.6.36-rc3, I did not mess with any of the 
new power savings settings.

Some more info: lspci says:
ATI Technologies Inc M24GL [Mobility FireGL V3200] (rev 80)
System info: Slackware 13.1, Mesa 7.8.1, Xserver 1.7.7.

Has this bug (or one like it) already been reported? And if not, what 
can I do to be of help? Should I open a bug report, and if so, where? 
What further info do you need (kernel config, xorg.conf)? I can build 
and test new kernels, but I don't know how to bisect them. Also, I don't 
know how to gather a call trace.

PJ