laptop problem:

How do I get a dvi monitor connected to a thinkpad laptop via a displayport docking station (via usb) to work in linux? (debian-based distros)

The screen goes bright green when its connected (so guessing its seeing a driver?) but thats all I get.

tried playing with xrandr options but nothing works
(other than switching the laptop screen off or on)

Whatever I try there the dvi monitor just stays the same bright green.

how do I send anything to that monitor?