Comment 11 for bug 564559

(In reply to comment #6)
> Just tried kernel 2.6.34-rc3 (not from mainline, self compiled, no source
> changes).
> - no EDID detection of the monitor (driver does that in UMS)

Can you attach your dmesg from 2.6.34-rc3? I suspect you need this patch:
http://git.kernel.org/?p=linux/kernel/git/airlied/drm-2.6.git;a=commitdiff;h=95beb690170e6ce918fe53c73a0fcc7cf64d704a

Finally, can you try 2.6.33 with the new_pll=0 radeon module param? E.g., set it when you load radeon:
modprobe radeon modeset=1 new_pll=0
or on the kernel command line:
radeon.new_pll=0