Bug#488277: I have exactly the same problem

[Eric Valette]

After updating to the new xserver on my nc6000 HP LAPTOP, the screen
connected on the docking station that can only do 1280x1024 is forced at
the flat panel resolution that is actually 1400x1050 meaning I see only
part of the screen on my external LCD monitor. If I force to change the
resolution to 1280x1024 using xrandr, it just kill the external display.
 Restoring the initial 1400x1050 does not restore the video on the
external dipslay. To restore it I have to call xrandr --auto and then Im
back to 1400x1050.

Of course, I did not change my xorg.conf at the beginning. Googling a
little bit I have added the new Randr 1.2 option to attach a specific
monitor to a specific video output (external LCD->VGA-0, Flat Panel to
LDVS). They are correctly associated now, but it did not change the
behavior.

So far the only trick I have found to support the external screen is to
explicitly shut down the flat panel using xrandr and then to change the
resolution manually to 1280x1024. I have put a docked script in my ~/bin
that automates it.

Looking at the Xorg.0.log, I have no error either. Will post my
xorg.conf and my Xorg.0.log monday when I'll be back to work.

-- eric