trident XP4m32 brightness change

[Mathieu Lacage]

hi,

If, under X, I try to change the brightness of my laptop's lcd panel
with the following command:
echo "brightness: 1" > /proc/acpi/toshiba/lcd

the screen resolution changes abruptly: it switches from 1024x768 (the
panel's native resolution) to what I believe is 320x.... forcing a VT
switch back and forth brings back the old resolution with the new
brightness. 

Is there something which can be done to make the trident driver
synchronize with the kernel-level brightness change ? Or is just a bug
in my linux vesafb driver (which, I suspect, is responsible for
performing the brightness change once it is requested through acpi).

Mathieu