Loki turns off the screen after 10-15 Minutes of inactivity. At the same time it looks the screen automatically.
When I wake the computer, the log in screen appears as it should and I can log in. But after logging in, the display stays black. I can see and move the cursor but that's all.
I can change to tty and restart lightdm with
sudo service lightdm restart but since this closes every opened program this isn't really helpful at all.
Somehow I manged to "revive" the screen once and I found that this ↑ prompt appears when the screen was locked. The prompt appears many, many times (I needed to press and hold esc for 10 seconds to close all these windows). Maybe this relates to freezing the screen?