It's a bit more complicated: when I reconnected and tried to use the external monitor, it was back to the original behaviour of showing just black on both panels. With the monitor connected by vga over either the ultrabase or built in vga port, I get the flickering red/black display. Unplugging the monitor puts things back to a working built in display. I have some more kernel log messages:
pr 12 12:15:32 joy kernel: [ 2022.623546] [drm:i915_gem_do_execbuffer] *ERROR* Object ffff88022e695e00 [handle 618, index 1] appears more than once in object list Apr 12 12:15:33 joy kernel: [ 2023.296025] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting Apr 12 12:15:34 joy kernel: [ 2024.153864] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting Apr 12 12:15:35 joy kernel: [ 2025.011692] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting Apr 12 12:15:36 joy kernel: [ 2025.859615] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting Apr 12 12:15:36 joy kernel: [ 2026.697493] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting Apr 12 12:15:37 joy kernel: [ 2027.545447] [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/749817 Title: natty regression: screen goes black when external monitor is connected -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
