https://bugs.kde.org/show_bug.cgi?id=520940
--- Comment #2 from Erik Skean <[email protected]> --- Thanks for the steer. I instrumented the sysfs sampler to log /sys/class/drm/card0-HDMI-A-1/status alongside /dpms on every change and caught another event with both values: 07:26:16 dpms=On status=connected (baseline) 07:42:34 dpms=Off status=connected <-- OFF fires while connector is still connected 08:51:22 dpms=On status=disconnected (wake; LG briefly drops HPD as it exits its own sleep) 08:51:25 dpms=On status=connected (reconnects 3s later) The 07:42:34 transition is the key datum: the kernel still reads status=connected at the instant DPMS goes Off. If the monitor had auto-powered itself off (auto-standby, energy-save, no-signal timeout, etc.) the status would have flipped to "disconnected" at that point. It did not. The brief status=disconnected at 08:51:22 happens during WAKE, not during OFF. That is the monitor entering/exiting its internal sleep in response to the GPU re-asserting signal on a connector that was held DPMS=Off for ~69 minutes. It is a consequence, not the initiator. login1 emitted DelayInhibited="sleep" PropertiesChanged at 07:42:33, exactly one second before the DPMS=Off transition. Monitors cannot emit dbus signals, so this is unambiguously a session/system-side actor. Kernel HPD / hot-plug events at runtime: still zero. dmesg -wT shows only boot-time amdgpu connector init; no transitions during any DPMS-off window. Monitor identification from EDID: - Manufacturer: GSM (LG Electronics), product 0x7767 - Monitor name descriptor: "LG ULTRAWIDE" - Serial: 309NTCZ7K435, manufactured week 9 of 2023 - Native 3440x1440 over HDMI, single output (no second display, no KVM, no dock, no MST tree) Monitor OSD walked and verified: - General -> Automatic Standby: Off - General -> Energy Saving: Off - No "Sleep Mode" or "Power Off Schedule" option present on this model - Auto Input Switch, DAS Mode, Adaptive-Sync, Smart Energy Saving: none active or not present - No remaining monitor-side auto-power feature is enabled Conclusion: the OFF event is compositor-initiated. PowerDevil's DPMSControl plugin is firing despite TurnOffDisplayWhenIdle=false and TurnOffDisplayIdleTimeoutSec=2147483647 (INT_MAX). The login1 sleep delay-inhibitor signal pattern reproduces 1:1 with every DPMS=Off transition. Happy to capture a KMS atomic-commit trace, or run kwin_wayland with KWIN_OUTPUT_DEBUG or similar, if a more direct trace of who is calling setDpmsMode would help triage further. -- You are receiving this mail because: You are watching all bug changes.
