Comment 95 for bug 814325

(In reply to comment #9)
> I can't make sense of this based on the commit... I'm afraid this might be
> timing related rather than an actual register change, since the register dumps
> before & after are identical.
>
> Can you isolate which part of the patch causes problems?

Argh, I'm terribly sorry for this but the actual offending commit was

drm/i915: disable PCH ports if needed when disabling a CRTC

Which needed a bit of fixing to apply to .38, but has the same failure in both the backport and the upstream kernel

http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-natty.git;a=commit;h=bbeaf8811ba070fd186dfcabc957044c3a1149ac