SUMMARY If the monitors turn off for any reason, night light will fail to activate. This is because of Displayport "hotplug", where sleeping displayport monitors are treated as unplugged. STEPS TO REPRODUCE 1. Turn off a displayport monitor before Night Light's activation time. 2. Turn it on after activation, it doesn't activate. OBSERVED RESULT Night Light never triggers EXPECTED RESULT Night light should work normally. SOFTWARE/OS VERSIONS Linux/KDE Plasma: 6.10 KDE Plasma Version: 6.15 KDE Frameworks Version: 6.6 Qt Version: 6.7.2 ADDITIONAL INFORMATION This can probably be fixed by checking night light status whenever a monitor is plugged or unplugged.
From looking at the codebase, this could probably be fixed by adding a check for monitor plug similar to how the suspend check works? https://invent.kde.org/plasma/kwin/-/blob/master/src/plugins/nightlight/nightlightmanager.cpp
Interesting, would you like to submit a patch?
Hello i am here to add that on gento kwin 6.4.4 with three monitors on an amd 7600xt the night colors are used only on one monitor after resume. clicking "temporarily disable" on the desktop widget immediately turns all monitors red (so it was in night state, just not applied), then flows to blue colors. So the suspend check does not work:)