I have Thinkpad T60 with Radeon x1400. It's native screen resolution is
1400x1040, but at work I connect it to external monitor Belinea 2485 S1W with
native resolution 1920x1200 via d-sub. when I set resolution of
external monitor to 1920x1200 the monitor shows resolution 1600x1200 and the
desktop has no left part. I'm forced to use 1600x1200 resolution to see all
desktop. The effect was on Fedora 9 and after upgrade to Fedora 10 it still remains (but krandrtray works better). I've tried many different xorg.conf configurations (with and without dualhead) and it always stays the same.
I had simmilar problems with radeon driver, described in bug #20558, after upgrade to Fedora 10. But it turned out to be kms drm problem.
Sounds like the regression the patch in bug 14570 introduced. Please try current git head of xrandr.
Does this issue occur with the preferred ati driver (xf86-vide-ati)? If so, please move this to the Driver/Radeon component.
Development of radeonhd has pretty much halted and development focus is on the ati driver. Please see http://www.x.org/wiki/radeonhd
If the issue does not exist in the ati driver (or if there is no response to this message), this bug will be closed as WONTFIX unless someone contributes a patch.
Closing due to lack of response. Please reopen and move to the Driver/Radeon
component if this issue persists with xf86-video-ati