Bug 450174

SUMMARY
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Plasma 5.24 on Wayland: when I connect an external monitor to my Optimus laptop (Intel iGPU + NVIDIA dGPU, without the NVIDIA driver), the only working mode is "unify outputs". If I choose "switch to laptop screen" the external monitor stays powered on, and if I choose "switch to external screen" sometimes it does nothing with both screens remaining powered on with the cursor only working in the laptop screen, and sometimes it does nothing with both screens remaining powered on with the cursor only working in the external screen.

This is without the NVIDIA driver. With the NVIDIA driver instead (Wayland) if I connect my laptop to an external monitor all I get is a black screen on my laptop, and I have to force reboot. Starting with Plasma 5.23.2 it used to work almost flawlessly.
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STEPS TO REPRODUCE
1. Connect an Optimus laptop to an external monitor via HDMI
2. Try to switch to the external screen or to unify the outputs
3. 

OBSERVED RESULT

The laptop screen doesn't turn off when "Switch to the external screen" is selected, and the external screen doesn't turn off when "Switch to the laptop screen" is selected.

EXPECTED RESULT

The laptop screen should turn off when "Switch to the external screen" is selected, and the external screen should turn off when "Switch to the laptop screen" is selected.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: any Linux distribution
KDE Plasma Version: 5.24.0
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION