On Saturday 13 September 2008, Pallipadi, Venkatesh wrote:
quoted text
> >We have too many entires in PAT list due to RAM pages being marked
> >UC by drivers. Unfortunately, there are no quick fixes that can fix
> >this for 2.6.27. However, we are aware of the problem here and
> >working on a more complete fix for this. We should have the patch
> >for it soon.
>
> Can you try the patch here
> http://www.ussg.iu.edu/hypermail/linux/kernel/0809.1/2074.html
> And report back whether that resolves the issue.

Yes, that solves the issue. The display is now free of artifacts again, 
both on logout and when I switch users in X.
The pat_memtype_list looks a lot more sane too (see attachment).

So it _was_ a regression caused by pat itself after all, and not the 
result of incorrect memory handling in the framebuffer code.
Could you take over the bug report #10843 in bugzilla (it is currently 
assigned to the framebuffer people) and ensure it gets closed once the 
patch gets accepted in Linus' tree?

I'm glad you were able to get this sorted out.

Feel free to add my:
Tested-by: Frans Pop <elendil@planet.nl>

Thanks,
FJP