SUMMARY Screen goes black / 0% brightness whenever I decrease screen brightness using Fn keys and I pass the 50% mark (50% -> 45%). STEPS TO REPRODUCE 1. Use Fn keys to increase brightness to 50%. 2. Press Fn key to decrease brightness (5% step). 3. Screen goes completely black / off. (Should be 45%) 4. Press decrease again, stays black. (Should be 40%) 5. Press Fn key to increase brightness. Screen is lit again. Shows 40% brightness. (Should be 45%). OBSERVED RESULT Screen goes black. EXPECTED RESULT Screen doesn't go black and there shouldn't be a 5% deviation in the end. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 6.4.5 KDE Frameworks Version: 6.18.0 Qt Version: 6.9.2 Kernel Version: 6.16.10-arch1-1 (64-bit) Graphics Platform: Wayland Graphics Processor: AMD Radeon Graphics ADDITIONAL INFORMATION
Can you run `cat /sys/class/backlight/*/brightness` and paste the output here, first when the brightness is at 50%, and then again when you reduce it to 45% to trigger the bug?
# increase brightness to 50 % with Fn+F6 $ cat /sys/class/backlight/*/brightness 32768 # decrease brightness with Fn+F5 (screen goes completely black) $ cat /sys/class/backlight/*/brightness 29491 # increase brightness with Fn+F6 (now at 45% and screen is lit) $ cat /sys/class/backlight/*/brightness 29491
Thanks. This seems like a GPU driver bug, or possibly even a hardware issue; a brightness value of 29491 should not be turning off the backlight entirely! That's whacko. I'd recommend reporting the issue upstream; see https://docs.mesa3d.org/bugs.html for how to do that.