Comment 18 for bug 564559

(In reply to comment #15)
> Just to prove it, I've just dug out a different monitor - this one is a Dell
> IN2010N at 1600x900... lo and behold this monitor works with KMS enabled. So I
> can't say for sure because I know nothing about the code, but "something to do
> with dual link DVI" would seem to be the most likely conclusion!

I didn't get the chance to test that as I don't have any monitor left that has a lower resolution. So combining our experiences it really looks like a DualLink-DVI signal problem.

> One other thing that I've noticed... at 2560x1600 on the 30 inch ( obviously
> with UMS ) I get really bad screen corruption in pretty much all apps.
> Scrolling pages seems to result in the bitmap not matching what was on screen
> previously, and so when you move the mouse over parts of the scrolled window it
> becomes obvious that what you see isn't what X actually thinks is there. Also,
> the KMail icon menu just completely corrupts after a ( short ) while, and again
> moving the mouse over it brings back the icons as they animate for the mouse
> over action. I realise that this may be a completely different bug, but I
> mention it because with the 1600x900 monitor and KMS it seems to not be
> happening...

Yes, me too (only for those corruptions when scrolling with nearly all applications - firefox, thundebird, kate, mousepad, konsole, gimp, gwenview, etc., but not with e.g. dolphin or amarok). Icons and the like are fine for me (KDE4 and XFCE). But I think that's another thing as this was introduced some time ago (I think from another DRM pull from upstream into Ubuntu Lucid).