Plasma doesn't start when external monitors are plugged in

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1

When I turn my laptop on while external monitors are connected, Plasma doesn’t start and SDDM just shows an unresponsive black screen with a cursor.
I’m using integrated intel graphics on Wayland, openSUSE Tumbleweed, Plasma 6.0.5, device is a Slimbook Hero.
I see [drm:nv_drm_atomic_commit [nvidia-drm]] ERROR: Flip event timeout on head 0 and head 1if I swith to the terminal, is that relevant?

If I’m already logged in when connecting it, the monitor works fine.
How should I start debugging this?

2

Sometimes, the external monitor (wired to the GPU output) will work but the laptop screen still shows the frozen SDDM screen.

3

I have a slightly different problem since Fedora transitioned to run SDDM under Wayland. In my case I get the black screen (with cursor, maybe?) when my only monitor is not turned on at boot.

Filed this as a bug against Fedora but there was no follow up.

4

Yep, that means the NVidia driver is at fault; after a pageflip timeout happens, KWin can’t present new frames on the screen

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5

Could also be hardware related. This case had intel graphics, too, I believe.

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6

This was since resolved, probably by a Tumbleweed or NVIDIA update

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