It is suspicious that it would only appear to fail whilst the monitor is off - that suggests we are missing a required wait for one of the control lines to power up.
Can you please 'echo 6 > /sys/modules/drm/parameters/debug' then xset dpms force off, wake it up (hopefully reproducing the issue) and then attach the output of dmesg? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1189639 Title: External Screen doesn't wake up from sleep To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1189639/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
