SUMMARY When i set the brightness to say, 70%, on my external monitor connected over mini-displayport, it works fine over dcc/ci as expected. however, when i restart my pc, plasma/kscreen/kwin still thinks it's 70%, but my monitor has reverted to 100% as that's what it's set to by default in the firmware. I know this is technically a bug in the monitor, that it doesen't store the DCC/CI brightness in it's flash, but i feel like this is something that could be fixed in plasmashell/kscreen/kwin as well. STEPS TO REPRODUCE 1. Set brightness to 70% on external monitor 2. Restart PC OBSERVED RESULT Monitor at 100% Brightness even though plasmashell/kscreen/kwin thinks it's 70% EXPECTED RESULT plasmashell/kscreen/kwin would reset back to 100% so it's in sync, OR plasmashell/kscreen/kwin sends the DCC/CI command to the monitor on login to set to 70% until i manually change it again. SOFTWARE/OS VERSIONS Operating System: Fedora Linux 42 KDE Plasma Version: 6.4.5 KDE Frameworks Version: 6.19.0 Qt Version: 6.9.2 Kernel Version: 6.17.4-200.fc42.x86_64 (64-bit) Graphics Platform: Wayland Processors: 4 × Intel® Core™ i5-7300HQ CPU @ 2.50GHz Memory: 24 GiB of RAM (23.3 GiB usable) Graphics Processor 1: Intel® HD Graphics 630 Graphics Processor 2: NVIDIA GeForce GTX 1050 Ti Manufacturer: ASUSTeK COMPUTER INC. Product Name: FX502VE System Version: 1.0 ADDITIONAL INFORMATION I'm fine with either solution i wrote in expected result. I usually only set the brightness to 70% when it's dark outside. I don't mind setting it manually every day, until https://bugs.kde.org/show_bug.cgi?id=413165 get's implemented, but it's annoying that i gotta first set it to 100% so the brightness syncs, and then back to 70%. I don't mind the brightness resetting to 100% when restart, that part's fine. But either behaviour is fine, i guess.
Thanks for the bug report. Can you please copy and paste the output of this into the report? Thanks. kscreen-doctor -o Also, what version of ddcutil is on your system? Thanks.
$ kscreen-doctor -o Output: 1 eDP-1 dce38afa-9269-4853-a652-b9ba8356d228 disabled connected priority 0 Panel replication source:0 Modes: 1:1920x1080@60*! 2:1280x1024@60 3:1280x1024@60 4:1024x768@60 5:1024x768@60 6:1280x800@60 7:1280x800@60 8:1600x900@60 9:1600x900@60 10:1368x768@60 11:1368x768@60 12:1280x720@60 13:1280x720@60 Geometry: 2560,1113 1920x1080 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic HDR: incapable Wide Color Gamut: incapable ICC profile: none Color profile source: EDID Color power preference: prefer efficiency and performance Brightness control: supported, set to 100% and dimming to 100% Color resolution: automatic (10), range: [6; 12] bits per color Allow EDR: always Output: 2 DP-1 6c54e07c-1306-4e8e-adc0-f96bdeead30a enabled connected priority 1 DisplayPort replication source:0 Modes: 14:2560x1440@60! 15:3840x2160@60 16:3840x2160@60 17:3840x2160@30 18:3840x2160@30 19:2560x1440@165* 20:2560x1440@120 21:1920x1080@165 22:1920x1080@120 23:1920x1080@120 24:1920x1080@100 25:1920x1080@60 26:1920x1080@60 27:1920x1080@60 28:1920x1080@50 29:1680x1050@60 30:1280x1024@75 31:1280x1024@60 32:1440x900@60 33:1280x720@120 34:1280x720@120 35:1280x720@100 36:1280x720@60 37:1280x720@60 38:1280x720@50 39:1024x768@75 40:1024x768@70 41:1024x768@60 42:800x600@75 43:800x600@72 44:800x600@60 45:800x600@56 46:720x576@50 47:720x576@50 48:720x480@60 49:720x480@60 50:720x480@60 51:720x480@60 52:640x480@75 53:640x480@73 54:640x480@67 55:640x480@60 56:640x480@60 Geometry: 0,0 2560x1440 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic HDR: incapable Wide Color Gamut: disabled ICC profile: /home/nex/linuxstuff/msi-optix-rtings-icc-profile.icm Color profile source: sRGB Color power preference: prefer efficiency and performance Brightness control: supported, set to 80% and dimming to 100% DDC/CI: allowed Color resolution: automatic (10), range: [6; 12] bits per color Allow EDR: unsupported nex@asus-nex ~ $ dnf list | rg "ddcutil" Updating and loading repositories: Fedora 42 - x86_64 - Updates 100% | 24.9 KiB/s | 16.4 KiB | 00m01s Repositories loaded. ddcutil.x86_64 2.2.1-1.fc42 updates libddcutil.x86_64 2.2.1-1.fc42 updates libddcutil.i686 2.2.1-1.fc42 updates libddcutil-devel.i686 2.2.1-1.fc42 updates libddcutil-devel.x86_64 2.2.1-1.fc42 updates
Thanks! I'll let the folks more knowledgeable about the brightness code take it from here.
I should also mention that while i've loaded the ICC profile in the past to try it, and system settings/kscreen remembers its path, I do not use it; I select "None" in the color profile dropdown.
I haven't been able to reproduce this anymore, so I'm closing it. Seems it has been fixed in the last few months. If it starts happening again, i'll re-open