I downgraded to: xserver-xorg-core 1.1.1-21 xserver-xorg-video-i810 1.7.2-4 and now it works again. I tried to take a screenshot with gnome-screenshot but the image is normal, I can't see the green distortion I see in my screen and the image size is 1400x1050 as expected. That's quite strange imho. Regards, Mattia