I have an HP Envy 15 with mobility 5830. Laptop panel works fine, however, the hdmi port connected to a dell 20" lcd produced garbled screen. I tried adding radeon.new_pll=0 on grub and it fixed the problem.
Using the git evergreen_accel branch xorg ati driver with 2.6.36-rc4 with airlied's drm-radeon-testing. Xorg version from ubuntu xorg-edgers ppa 1.9.0+git20100902+server-1.9-branch.79ee78de-0ubuntu0sarvatt. Mesa version from ppa 7.9.0+git20100915.e0b6df4f-0ubuntu0sarvatt.
Created attachment 38728 [details]
Created attachment 38729 [details]
Created attachment 38730 [details]
Does this set of kernel patches help (against 2.6.36):
Yes it is working with the patches.
fixed in drm-next.