xrandr: how to tell it that a screen size is supported?

[Dotan Cohen]

A Kubuntu 9.10 machine runs at 1680x1050 resolution with no problems
if the KVM is switched to that machine when it is booted. If the KVM
is switched to another machine, then this machine loads at a very low
resolution and I cannot configure the proper resolution with xrandr:

ety at ecd:~$ xrandr -s 1680x1050
Size 1680x1050 not found in available modes
ety at ecd:~$ xrandr --fb 1680x1050
xrandr: screen cannot be larger than 1360x1360 (desired size 1680x1050)
ety at ecd:~$

How can I either:
1) Configure the machine to always use 1680x1050 no matter how it is booted?
-or-
2) Tell xrandr that 1680x1050 is fine?

Thanks.

-- 
Dotan Cohen

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http://what-is-what.com