SUMMARY Nightlight turns off when launching Nvidia X Settings. The option is still toggled on, but night color doesn't work anymore. To fix it, you need to disable the night color(animation from the chosen color to normal does happen/occur) and re-enable it. Every opening of the NVIDIA X Server Settings causes the Night Color to stop working until re-enabled. STEPS TO REPRODUCE 1. Turn on Night Color 2. Open application NVIDIA X Server Settings OBSERVED RESULT - Night Color turns off EXPECTED RESULT - None SOFTWARE/OS VERSIONS Linux/KDE Plasma: Arch Linux x86_64(last update 02.09.2020) KDE Plasma Version: 5.19.5 KDE Frameworks Version: 5.19 Qt Version: - QMake version 3.1 - Using Qt version 5.15.0 in /usr/lib ADDITIONAL INFORMATION NVIDIA Driver Version: 450.66
The nvidia-settings tool resets the X11 gamma ramps even if you didn't configure any gamma curve related settings in the tool. That's a bug that you could report to NVIDIA developers. Additionally, X11 unfortunately has no way to cascade gamma curves, so each tool replaces the gamma curve settings of each other tool. *** This bug has been marked as a duplicate of bug 413134 ***