On Kubuntu 20.04 with Plasma 5.18, I'm not use xrandr: powerdevil: Backend loaded, loading core powerdevil: Core loaded, initializing backend powerdevil: Xrandr not supported, trying ddc, helper powerdevil: [DDCutilBrightness] compiled without DDC/CI support powerdevil: Falling back to helper to get brightness
It looks like it is using /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight The device is a laptop with Optimus and using Intel HD 630 for the display. -- Oded
