Recently, a problem with the Plasma 6.7 update led me to do some research on Plasma configuration, including the plasma login manager, Plasma’s new default login manager.
For some time now I’ve been having trouble customizing the plasma login manager. The configuration module has a button to ‘Apply Plasma settings’ for plasma login manager at System Settings. However, it doesn’t actually apply ALL the settings.
In the problem I had, it wasn’t applying the setting that allowed game controllers to act as a mouse. An uncalibrated controller was pushing my mouse pointer to the corner of the screen, regardless of my mouse movements. The solution is to disable this option in the system settings.
However, the problem persisted in the plasma login manager, even after clicking the ‘Apply Plasma settings’ button in the plasma login manager control module. In other words, the module doesn’t apply ALL the settings to plasma-login-manager, but only some.
To solve this problem, I discovered that plasma-login-manager runs with a user named ‘plasmalogin’, whose ‘/home’ folder is located, in CachyOS, at ‘/var/lib/plasmalogin’.
Once this was discovered, and knowing which configuration file to adjust, you just need to make the correction directly in this folder, as if it were a regular user’s folder, and these settings will be reflected in the Plasma environment loaded for plasma-login-manager.
To fix the game controller problem, I simply edited the ‘kwinrc’ file located in the ‘/var/lib/plasmalogin/.config/’ folder.
I also had an incorrect dual screen configuration in plasma-login-manager. To fix this, I moved my ‘kwinoutputconfig.json’ file (which stores these settings) to the ‘/var/lib/plasmalogin/.config/’ folder.
This requires admin permission and is certainly not the simplest thing to do. But if you know where and how your Plasma settings are stored, you can actually adjust any setting you want for plasma-login-manager. At least until KDE can provide an easier way to do this.
I hope you find this information helpful.