Created attachment 188587 [details]
KWin Support Dump Of Impacted System

SUMMARY

Powerdevil's "idle" function is failing to trigger the DPMS power off routine. This leaves all of the connected monitors on and active even after the idle timeout has passed.

This appears to be related to the following log entries:

org_kde_powerdevil: DPMS: registering idle timeout (screen lock activating) after 20000ms
org_kde_powerdevil: Native interface revision mismatch (requested 1 / available 2) for interface QWaylandApplication

This problem immediately started occurring after upgrading to the 6.6 Beta branch.

STEPS TO REPRODUCE
1. Verify or configure screen to turn off after locked for 20 seconds.
1. Lock screen.
2. Wait 30 to 60 seconds.

OBSERVED RESULT

Screens stays active and on even after exceeding the screen off idle period.

Relevant logs:
org_kde_powerdevil[45934]: DPMS: registering idle timeout (screen lock activating) after 20000ms
org_kde_powerdevil[45934]: Native interface revision mismatch (requested 1 / available 2) for interface QWaylandApplication
org_kde_powerdevil[45934]: DPMS: registering idle timeout (screen unlocked) after 900000ms
org_kde_powerdevil[45934]: Native interface revision mismatch (requested 1 / available 2) for interface QWaylandApplication
kscreenlocker_greet[48217]: Failed to write to the pipe: Bad file descriptor.

EXPECTED RESULT

Screens go idle and auto power off after 20 seconds on the lock screen.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch 6.18.5-arch1-1 (64-bit) (Wayland)
KDE Plasma Version: 6.5.90
KDE Frameworks Version: 6.22.0
Qt Version: 6.11.0