I'm commenting to explain my solution for the posteriority:
- It seems that watching a video from tv-out in Windows (dual boot) screwed up my monitor ( acer al2216w ). I started getting the "bad edid checksum" errors from X.
- The problem appeared simultaneously on Ubuntu 9.04 and Debian "Lenny" (yes, I have 3 operating systems on my hard drive).
- I solved it by "rebooting" my monitor - that is I unplugged it for a while, and reconnected it. This should definitely be tried before any other tweaks.
- Even without monitor reboot, the windows drivers worked fine; it was the Ubuntu drivers that required it.
I'm commenting to explain my solution for the posteriority:
- It seems that watching a video from tv-out in Windows (dual boot) screwed up my monitor ( acer al2216w ). I started getting the "bad edid checksum" errors from X.
- The problem appeared simultaneously on Ubuntu 9.04 and Debian "Lenny" (yes, I have 3 operating systems on my hard drive).
- I solved it by "rebooting" my monitor - that is I unplugged it for a while, and reconnected it. This should definitely be tried before any other tweaks.
- Even without monitor reboot, the windows drivers worked fine; it was the Ubuntu drivers that required it.