This has been happening to me for about ~2 months too: hangs, typically after resuming from suspend, either immediately after resume or within a couple of minutes. Hard power-cycle by holding down power button is only way out (CTRL+ALT+F1 unresponsive and entire laptop appears frozen).
Think it's definitely related to external displays (I use a mini-DP cable) as I don't seem to have the issue when just using the laptop's internal screen. Environment: * ThinkPad X1 Carbon 3rd Gen (2015, Broadwell) * Integrated Intel HD5500 graphics * Stock Ubuntu 14.04/Unity with Kernel 3.19. The attached crash log has no less than 2549 occurrences of the ominous "[drm:gen8_irq_handler [i915_bpo]] *ERROR* The master control interrupt lied (SDE)!". These tend to occur more often just before freezes and suggest the following might be related: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1488719 ** Attachment added: "crash_rep.txt" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1559308/+attachment/4671250/+files/crash_rep.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1559308 Title: Plugging HDMI screen in causes system hang To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1559308/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
