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-X, which is subscribed to xserver-xorg-video-intel in 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 _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
