This looks like potentially the EDID is corrupted. According to http://en.wikipedia.org/wiki/Extended_display_identification_data the first 8 bytes should be 00ff ffff ffff ff00, however we see the first 8 bytes in the dmesg showing all 0xff. So the difference is 0xff+ 0xff = 0x1fe, but looks like the remainder is only a char, so we get 0xfe or 254.
1) You can verify the EDID using the read-edid package. Then running 'sudo get-edid | xxd' to check. In addition 'sudo get-edid > parse-edid' will give you mode information that may be helpful as well. Can you paste that info into the bug? 2) It would be good to check that the monitor works in 11.04 and see what the dmesgs show. I wonder if we're getting the same messages about EDID or any messages such as 'Fixing EDID header, your hardware may be failing.', please attach this information as well. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/914437 Title: Second display not recognized anymore; "EDID checksum is invalid" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/914437/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
