SUMMARY When you enable the "Presentation Mode" option accessible from the Display Configuration icon from the System Tray and disable it again, it will still be enabled until you restart plasmashell. STEPS TO REPRODUCE 1. Check the option "Presentation Mode" from the Display Configuration icon from the System Tray to enable it 2. Check it again to disable it OBSERVED RESULT The Presentation Mode will be kept enabled even when the checkbox is unchecked: the screen won't automatically be turned off as expected from "Screen Energy Saving" setting, not sure about the automated suspension since I don't use it. Killing plasmashell and starting it again "fixes" the issue. EXPECTED RESULT When unchecking the Presentation Mode box from the Display Configuration menu it should disable the mode. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: KDE Frameworks Version: Qt Version: ADDITIONAL INFORMATION
Can confirm. Interestingly enough, the Battery & Brightness applet doesn't list any active inhibitions while Presentation Mode is on, so it must be using some other mechanism to suppress power management. Perhaps it's just a matter of porting it to use the normal method.
Also noticed this bug on Manjaro. KDE Plasma Version: 5.21.4 KDE Frameworks Version: 5.81.0 Qt Version: 5.15.2 Kernel Version: 5.11.18-1-MANJARO
Can confirm this too. Operating System: KDE neon 5.22 KDE Plasma Version: 5.22.5 KDE Frameworks Version: 5.85.0 Qt Version: 5.15.3 Kernel Version: 5.11.0-34-generic (64-bit)
Aha, this was fixed automatically by the fix for Bug 433675, since they use the same data source! *** This bug has been marked as a duplicate of bug 433675 ***