I had a similar problem in Ubuntu Edgy. So I don't want to add a new bug, and subscribe to this bug.
I have a Radeon X300 card with a 30" LCD TV Videoseven LTV30C, the native LCD resolution is 1280x768. But 1280x1024 is the maximum resolution reported and was detected OK and worked fine with a fresh install (automatically selected as the default resolution). The problem is with the native resolution 1280x768: It was detected Ok as a possible resolution (an advance in comparison with previous ubuntu versions), but timings were not OK, so screen flashes. Reading the X log, I see the additional mode data reported by the monitor. It is ok and works fine if used in a Modeline. I think this is a bug (or an additional requirement) that the timings of additional modes reported by the monitor would be used if they are not, or revised if they are used incorrectly. I build and sell computers and try people use Linux, but the first thing a person see is the screen. I thing it is very important a robust screen detection. I use 3 widescreen monitors (17" laptop 1920x1200, 19" Wide 1400x900, and 30" Wide 1280x768), with different resolutions and in the last two I needed to edit the config manually. I am commited to help to make better the user experience, I am used to make installations in different kinds of hardware, so I can report about fresh installations without problem. Thank You -- [mga] mode validation seems to treat ModeLines and DDC dtimings differently https://launchpad.net/bugs/12502 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
