I've just had this happen on my ThinkPad T420. This comment includes the i915_error_state from immediately after the hang; I'll follow on with dmesg and Xorg.0.log.
** Attachment added: "i915_error_state" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/947543/+attachment/2956259/+files/i915_error_state -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/947543 Title: Lenovo x220 froze and display went blank while switching workplaces To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/947543/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
