I am having similar problems on a lenovo T520. Ubuntu 11.10 worked fine but could not talk to the docking station graphic ports. Backtrack 5.2 (an 11.10 branch) worked fine also (again minus docking station). 12.04 can talk to the docking station graphics ports but frequently hangs. I can run it in failsafe graphics mode and it hangs much less often.
I am having similar problems on a lenovo T520. Ubuntu 11.10 worked fine but could not talk to the docking station graphic ports. Backtrack 5.2 (an 11.10 branch) worked fine also (again minus docking station). 12.04 can talk to the docking station graphics ports but frequently hangs. I can run it in failsafe graphics mode and it hangs much less often.