After reporting this bug I noticed that the DVD drive in the dock in question was removable. When the drive is removed from the dock, the laptop can be docked / undocked, and suspend will still work when selected by menu option (but not from simply closing the lid).
The drive is Model UJ82, Serial Ultrabay Slim DVD Multi IV Lenovo branding, but says made by Panasonic. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/885279 Title: Thinkpad X220 fails to suspend after removal from dock To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/pm-utils/+bug/885279/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs