SUMMARY If I plug in or unplug the laptop's AC adapter after the screen has gone to sleep the screen will wake up and the backlight will be at 100%, no matter what the brightness level was before the screen went to sleep. STEPS TO REPRODUCE 1. Lower the backlight brightness to something visibly less than 100% 2. Leave the system alone until the screen goes to sleep 3. Plug in or unplug the AC adapter. OBSERVED RESULT The screen wakes up and the backlight is at 100% brightness. EXPECTED RESULT The screen should wake up and the backlight should be at whatever level it was before the screen went to sleep. SOFTWARE/OS VERSIONS Linux: Arch Linux KDE Plasma Version: 5.17.3-1 KDE Frameworks Version: 5.64.0-1 Qt Version: 5.13.2-3 xorg-server version: 1.20.5-4 ADDITIONAL INFORMATION The laptop is HP 250 G7, model 6MQ29EA. It has Intel Core i3 7020U: 00:02.0 VGA compatible controller [0300]: Intel Corporation HD Graphics 620 [8086:5916] (rev 02) And the screen: Manufacturer: BOE Model: 687 Serial#: 0 I don't have this problem on an older HP Compaq 6720s laptop, which has Intel 965 GM(E?) graphics.
This problem is gone since I updated to Plasma 5.20, Linux 5.8.14, etc.
I also have this problem. Linux: Arch Linux KDE Plasma version: 5.21.1-1 KDE Frameworks version: 5.79.0-1 Qt version: 5.15.2-5 xorg-server version: 1.20.10-3 Laptop: Lenovo ThinkPad T14
Are either of you able to reproduce this on Plasma 6.3.2 or later?
Actually, this looks like a duplicate of 494408, which was fixed. If you're still experiencing this bug, please open a new report. Thanks! *** This bug has been marked as a duplicate of bug 494408 ***