Comment # 7 on bug 83422 from Michel Dänzer

(In reply to comment #6)
> my xorg.conf is empty. if i add your lines the complete screen turns black
> the next time i login making kubuntu unusable.

Sounds like you didn't create a valid xorg.conf. Something like this should
work:

Section "Device"
        Identifier "default"
        Option "AccelMethod" "glamor"
EndSection


> or is this update available through the update center?

No idea, but there are PPAs.