Whenever I launch "kcmshell5 kscreen" as a regular user, the slider needed to change the display resolution is absent. I have to run "sudo kcmshell5 kscreen" in order to see it. Maybe this is by design, but I thought I'd mention it anyway. The other problem is that the KScreen settings often don't display at all in the latter case. Half the time, I see a "No KScreen backend found. Please check your KScreen installation." error message instead. I'll attach screenshots to illustrate my points shortly. Reproducible: Always
Created attachment 95374 [details] Regular User
Created attachment 95375 [details] Super User
I'm seeing the same thing (no kscreen backend) whether using kcmshell5 or just opening the option from system settings, as either regular or super user. I'm on Gentoo running kscreen version 5.7.3, so not sure if it's similar symptoms different problem, or same problem, but thought it'd be worth mentioning.
Could you run kscreen-doctor --info and kscreen-doctor --outputs and paste the output in this bugreport? The kscreen backend can fail to load if you have the wrong plugin path set (QT_PLUGIN_PATH env var), if it's wrong, adjust it so that it finds your kscreen backend plugin. This is a local configuration problem, or may need to be fixed in the packaging.
Sebastian: I'm not sure whether you're talking to Herb or myself (or both). I currently can't reproduce this issue at my end (on KScreen v5.8.1). For the record, the "QT_PLUGIN_PATH" environment variable is not set here. I guess this means the KScreen backend is being found in the default location (so no changes are necessary). Nonetheless, remember that I was only seeing the "No KScreen backend found" error message *half* the time. I was definitely not fiddling around with environment variables in-between attempts (e.g. just for kicks). This leads me to believe that the cause of the problem lay elsewhere. One thing I will note now is that the settings are blank - i.e. the dialog looks like that of the second screenshot (albeit minus the error message) - whenever I launch KScreen via 'sudo' (or 'su') these days. So, I will provide the output you've requested in this (i.e. 'su') case. Note that the "QT_PLUGIN_PATH" environment variable is still not set. xavion@Desktop /h/xavion> kscreen-doctor --info Environment: * KSCREEN_BACKEND : [not set] * KSCREEN_BACKEND_INPROCESS : [not set] * KSCREEN_LOGGING : [not set] Logging to : /root/.local/share/kscreen/kscreen.log Preferred KScreen backend : KSC_XRandR.so Available KScreen backends: * KSC_Fake.so: /usr/lib/qt/plugins/kf5/kscreen/KSC_Fake.so * KSC_KWayland.so: /usr/lib/qt/plugins/kf5/kscreen/KSC_KWayland.so * KSC_QScreen.so: /usr/lib/qt/plugins/kf5/kscreen/KSC_QScreen.so * KSC_XRandR.so: /usr/lib/qt/plugins/kf5/kscreen/KSC_XRandR.so * KSC_XRandR11.so: /usr/lib/qt/plugins/kf5/kscreen/KSC_XRandR11.so xavion@Desktop /h/xavion> kscreen-doctor --outputs (No output - it just hangs indefinitely and I have to hit "Ctrl+C" to quit each time)
You shouldn't be running it as root, though...
That may be so, but remember - in my first post - that I had to run it as 'root' (as it wouldn't work at all as a regular user). I was simply doing the same now for the sake of completeness, not because I thought it was the right (i.e. normal) way to go.