I have an old Compaq V5000 laptop, updated to SL6.8 and with KDE, which 
has normally done what I have asked of it.  Over the past few weeks its 
internal display has been unusable although an external VGA monitor 
works fine with System Settings at 'Unify outputs'.  The problem exists 
from power-up; a raster is displayed, and colours change, but text and 
windows are unrecognisable. When the problem first appeared it would 
often go away on power cycling, but now it seems locked in.

xrandr output looks normal and the only hint I see in Xorg.0.log is:

(WW) intel(0): Output LVDS1: Strange aspect ratio (289/21), consider 
adding a quirk

I haven't yet resorted to a screwdriver (or a quirk), and would welcome 
suggestions.

Thanks

John P