I recently started using my Samsung 204T as an external monitor for my laptop. I have it connected with VGA, and I setup my xorg.conf to fit both resolutions in virtual resolution (1680x1050 for laptop and 1600x1200 for external, giving 3280x2250 virtual). I also use this command:
to use my external in the vertical position. It works fine until about 10 or 15 minutes in the vertical mode. The external monitor starts displaying flickering scan lines. Returning to horizontal mode and turning the monitor off/on stops the flickering.
xrandr --output LVDS --mode 1680x1050 --output VGA --rotate left --mode 1600x1200
I have turned off compiz, and use metacity, but the problem still persists. Any ideas as to what might be happening? I have an Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller card.