I think I'm also affected by this issue (Thinkpad T450s). When changing the power management behavior for a closed lid (AC and Battery) to not suspend, I have no issues. I can then dock and undock. So this would be a work around.
This issue is clearly related to the suspending behavior of a closed lid during docking. I even get a freeze when I would simply shutdown the system. I think it even freezes when I wanted to start a new session while docked. $ uname -a Linux markushost 4.15.0-45-generic #48-Ubuntu SMP Tue Jan 29 16:28:13 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1575334 Title: Docking thinkpad laptop causes a complete system freeze To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1575334/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
