When the system enter the Screen Energy Saving mode, both the connected monitors powers off but after a couple of seconds they wake up again.
STEPS TO REPRODUCE
1. Into "settings > power managment > energy saving" enable "Screen Energy Saving" and set a timer
After the timer expires, screens go black but after a couple of seconds, both of my monitors turn on again without any interaction from me.
While debugging the issue I found out that killing the "kscreen_backend_launcher" process solves the issue and let the monitor sleep successfully.
After the timer expires, screens go black and stays powered off until it detect an user interaction
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: 5.25.4
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5
System is up do date.
I have 2 monitors connected, the primary one with DP and the other one with HDMI.
The gpu is a radeon rx6600xt.
Update and more info:
OBSERVED RESULT: When the screen forcefully wake up from the very short sleep, all the open windows are moved into the primary display.
EXPECTED RESULT: With "kscreen_backend_launcher" process killed, the windows are not rearranged and the windows stays as before the sleep.
On my Lenovo X1 Carbon I confirm that this is true. I kill the kscreen_backend background process and laptop sleeps as it should.
UPDATE: Still happening in 5.26.1
I have a similar issue, but it happens after the monitors are off for a couple hours. One monitor wakes, the backlight comes on, the OSD says "DisplayPort: No Input", and the monitor goes back to sleep. Then the other wakes and does the exact same thing, then back to the first in an infinite loop. This continues until I wake the system.
On logs I see massive spam from kscreen_backend_launcher every 5 seconds, which is the same interval as the monitors waking.
When I wake screen kscreenlocker is broken - the background is there but no greeter, impossible to log in. I can open a TTY but loginctl unlock-session does nothing, nor does killing kscreenlocker. The best solution I've found is to kill sddm, but this starts a new session I lose everything I had open. Probably a second bug, but it happens 100% of the time after kscreen_backend_launcher starts waking the screens, so likely related in some way.
I can also reproduce windows moving by running xset dpms force off and then waking monitors immediately after they power off. For me everything goes to my second screen but I think this is just GPU port order (plasma defaults to my second screen on a fresh install too).
Radeon RX 6600 (non-XT)
Monitors are both Asus PB278Q on displayport at 1440p
Second monitor in portrait orientation
Update: Killing kscreen_backend_launcher did NOT fix my issue, so it appears to be unrelated. I'll file a separate report.
Can you confirm whether it's still happening in Plasma 5.27.1, Erik?
> Can you confirm whether it's still happening in Plasma 5.27.1, Erik?
Yes, indeed, it's still happening in Plasma 5.27.1.
Thanks for the info!
The same problem persists through KDE plasma 5.27.5
Still happening with 5.27.7.
Still happening with 5.27.7-2 on Archlinux and Plasma up-to-date.
Monitor turn off after timer if i run " killall kscreen_backend_launcher"
Happening on Plasma 5.27.7, still!
Still happening 10/14 on KDE Plasma 5.27.8.
KDE Frameworks Version: 5.11.0
Qt VersioN: 5.15.10
Kernel Version: 6.5.7-300.fc39.x86_64
Happening on Plasma 5.27.7
(In reply to 张文超 from comment #14)
> Happening on Plasma 5.27.8
This bug is appalling... if you can't fix this, may as well just shut the project down and give up. Having your screen glowing brightly all night is an embarrassment to Linux.
Hello, I am experiencing the same issue on Archlinux. My Monitors are connected via, HDMI and Displayport. When the Timeout is reached, the monitors begin to turn off, then the 1st one enters Power Saving Mode and is effectively off. The 2nd monitor however does not reach this state and then a few seconds later, both monitors turn back on. It happens even if Dim screen is enabled or not.
Operating System: EndeavourOS
KDE Plasma Version: 5.27.10
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.12
Kernel Version: 6.7.6-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 20 × 12th Gen Intel® Core™ i7-12700K
Memory: 31.1 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 770