When I assign a key combination to turn off the screen and apply it the display output stays off only for one second and then power on again automatically ...
STEPS TO REPRODUCE
1. Go to System Settings > Shortcuts > Global Shortcuts > Power Management > Action Turn Off Screen.
2. Assign a key combination.
3. Apply it.
The display output stays off only for one second and then power on again.
The display output stays off and power on again only when activated by the user.
Linux/KDE Plasma: Kubuntu 19.10
(available in About System)
KDE Plasma Version: 5.17.1
KDE Frameworks Version: 5.62.0
Qt Version: 5.12.4
Plus Kubuntu backports PPA.
Is this a recent regression with 5.17?
As I can remember I have tested turning off the screen with a keyboard shortcut some time ago and then it didn't work, too - may be with Plasma 5.17.0 ...
Still not working for me in Plasma 5.18 Beta ...
If the screen is connected by DisplayPort, this might be related to bug 422455 : kdisplay awakes the screen as soon as it gets turned off by power saving.
Having the same issue.
Operating System: Kubuntu 20.04
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8
Kernel Version: 5.4.0-66-generic
OS Type: 64-bit
Processors: 12 × Intel® Core™ i7-8700 CPU @ 3.20GHz
Memory: 15,6 GiB of RAM
Note that I am using two screens, one with an HDMI connector and the other with DisplayPort.
Seems like this issue has been found on Reddit: https://www.reddit.com/r/kde/comments/ewbqst/display_doesnt_sleep_in_power_save_mode/
I disabled kscreen and the issue disappeared, but I would like to keep kscreen active.
I have also removed kscreen2 from startup and the issue was fixed, but now I have to make my external display as "default", and change settings after each startup.
Have anyone found any other way to solve the issue?