Compiz freezes when undocking Lenovo T450s

[Cs-gon]

When undocking my Lenovo T450s from the docking station (with external monitor connected), compiz frequently freezes, especially when an application is running, that does a lot of screen updates (i.e. terminal with top running at a low refresh frequency, or something like glxgears).

This happens since updating a 14.04 system to the Wily HWE stack, but it is also reproducible when using Wily or Xenial.

When compiz freezes, the screen gets kinda corrupted (will attach an screen shot). The screen does not get updated, only the mouse cursor works. When docking the notebook again, compiz recovers most of the time. Sometimes though, nothing happens and compiz keeps frozen. In this state only a restart of compiz or the X-Server (from the text console) help to get the system usable again.

When doing a stack trace on compiz, it hangs in xcb_wait_for_reply / wait_for_reply / _xcb_conn_wait. I will attach the full stack trace.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.