Ubuntu – 15.10 Dell XPS 15 (9550) External Monitor not waking


I'm in Ubuntu 15.10, with Kernel 4.3. Things are working better than I could ever imagine. Other than ONE bug…

When my laptop turns off it's screen and my external monitor's screen (I have it set for 5 minutes, in case I forget to lock the laptop), The external monitor never wakes up.

I have it hooked up with an HDMI to DVI cable. It works perfect other then it not waking up.

If I reboot with the cable plugged in, it still doesn't wake up.

If I unplug it and reboot, it wakes up.

The strange thing is that, I think Ubuntu thinks it did wake up. The reason I say that is because it doesn't gather my windows into the main screen until I unplug the HDMI cable. I even see the screen flicker as if the driver noticed a cable has been unplugged and it needs to do something.

So my questions are: Anyone know how to fix this? Or, if anything, know a command line command to wake the 2nd monitor?


EDIT: This might be fixed in kernel 4.7 per this article.

EDIT: This still happens with a standard HDMI cable.

Best Answer