SUMMARY STEPS TO REPRODUCE 1. Change the gamma in System Preferences > Screen & Monitor > Gamma 2. Save the configuration 3. Reboot the PC OBSERVED RESULT At the startup of the system your corrections are not active, to activate you need to go manually to the screen of gamma settings, then the corrections show up. EXPECTED RESULT The gamma corrections start automatically with the system. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.16.5 KDE Frameworks Version: Qt Version: ADDITIONAL INFORMATION I dont have any night mode or custom color installed. There is a bug that says that this happen because a conflict with night mode, but I dont have a night mode or so. The so-called bug is this: https://bugs.kde.org/show_bug.cgi?id=413134
This is also confirmed as present in Plasma 5.21 1) Set Gamma in System Preferences. 2) Reboot 3) Gamma will not return to the correct settings until you physically go back into the Gamma page of System Prefs. (Resuming from sleep doesn't have this bug). KDE Plasma Version : 5.21.0 KDE Frameworks Version : 5.79.0 Qt : 5.15.2
> but I dont have a night mode or so. It's packaged as part of kwin. In a recent for-nightmode fix we force apply what we think the state should be on bootup. I can believe this is a manifiestation of that. Maybe the fastest fix is to port kgamma to talk to kwin instead of doing it's own thing so we have a central source of truth.
As per comment 1, this bug is still present in 5.21.1, no workarounds found other than to manually enter gamma settings on every reboot.
The bug is still present in 5.27.8.