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I have my desktop computer with Arch (SDDM, KDE, AMD 6600XT with amdgpu), a work laptop (windows, doesn't affect this) and a Dell P2715Q monitor. DisplayPort cable goes to the desktop, HDMI cable goes to the laptop.
If the monitor is switched to the DP input and I turn on the desktop, everything is fine.
If it's switched to another input and I turn on the desktop, it boots and everything runs but when I switch the input to DP it doesn't show SDDM.
I can Ctrl+Alt+F3 to open a terminal and that shows, and I can Ctrl+Alt+Del to reboot the computer and I get the usual system log showing what's happening until it reboots, and then we're back to the first case of a happy path.
I suspect this has to do with how Arch can (or can't) see the monitor when it's switched to the HDMI input. Is there a way to either force SDDM to "think" the DP-connected monitor is there anyway, or to check for it every few seconds? (Also, I don't fully understand how this is all working behind the scenes, so any enlightenment on the topic will be appreciated). I used to have a (maybe related) issue back when I used X11 (wayland now) when the monitor was put to sleep while in use by the desktop but that particular issue went away a while back, maybe that's a clue here.
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