i915 and hardcoded 75 Hz refresh rate?

[Andreas Schildbach]

Hi everyone,

I'd like to connect a Dell 2405 external display to my new Dell Latitude 
X1, which is equipped with an i915GMS.

The only vertical refresh rate the 2405 will accept at its native 
resolution of 1920 x 1200 is 60 Hz.

Unfortunately, the i810 driver that comes with Xorg 6.8.2-15 (Ubuntu 
Breezy) always sets the refresh rate to 75 Hz, regardless of what I 
specify in the various modelines I tried: 640 x 480 @ 60 Hz, 1024 x 768 
@ 60 Hz, 1280 x 1024 @ 60 Hz and I guess also 1600 x 1200, 1680 x 1050 
and 1920 x 1200 (on these, the monitor only displays "cannot display mode").

Is there any way to override the hardcoded 75 Hz vertical refresh rate?

Regards,

Andreas