Hello, on my laptop (Thinkpad X240) the screen brightness can be changed by Fn+F and via the battery context menu when the battery icon in the task bar is selected. Both ways work fine. Actual Results: When an external monitor has been connected (primary monitor) and disconnected again, the screen brightness can not be changed anymore. After a reboot everything works again. The screen brightness can still be changed when changing the values in /sys/class/backlight/intel_backlight/brightness but not via Fn+F or via battery context menu. So it seems that for some reason, the /sys/class/.../brightness is not changed anymore once an external monitor was connected and disconnected again. Expected Result: After disconnecting the external monitor the screen brightness should be changeable. Output of journalctl does not give obvious errors just messages like this: kscreen.xcb.helper: RRNotify_OutputProperty (ignored) kscreen.xcb.helper: Output: 67 kscreen.xcb.helper: Property: Backlight kscreen.xcb.helper: State (newValue, Deleted): 0 Above messages appear in both cases: screen brightness is changeable or is not changeable.
I could be wrong, but this feels like it's more about KWin than the battery monitor.
Yes, you are wrong. KWin is not responsible for screen brightness.
Hello, I recently updated my openSUSE from 42.2 to 42.3 and I can no longer reproduce the reported bug. Even after plugging in and unplugging again an external monitor I can still change the screen brightness. So the bug seems to be solved. Thx to whoever solved this problem.