SUMMARY When Screen is set to turn off when locked it will turn off and then turn on again after a couple of seconds, even without any input. I had this issue for a while on EndevourOs and assumed it was fixed after not seeing it in 6.3 on cachyOS, it then started to happen again after updating to 6.4 this week. This seems the same behavior of this very old bug with Kscreen Bug 457726 STEPS TO REPRODUCE 1. On Power management, set the screen to turn off when locked 2. Lock your screen 3. Wait around 10-15 seconds OBSERVED RESULT The screen will turn on without input EXPECTED RESULT The screen should keep off until an input is made SOFTWARE/OS VERSIONS Linux: 6.15.3-2-cachyos KDE Plasma Version: 6.4.0 KDE Frameworks Version: 6.15.0 Qt Version: 6.9.1
Are you using the X11 session? Does it happen on both X11 and Wayland, or only one session type?
I was using wayland session but I was able to reproduce the same issue with plasma-x11-session Here is my power settings https://imgur.com/a/5icuWfO Here is my detailed computer info if any help: Operating System: CachyOS Linux KDE Plasma Version: 6.4.0 KDE Frameworks Version: 6.15.0 Qt Version: 6.9.1 Kernel Version: 6.15.3-2-cachyos (64-bit) Graphics Platform: Wayland Processors: 12 × AMD Ryzen 5 3600 6-Core Processor Memory: 32 GiB of RAM (31,3 GiB usable) Graphics Processor: AMD Radeon RX 6700 XT Manufacturer: GALAXY Product Name: GALAX B450M System Version: G10g
I also started having this bug with Plasma 6.4.0, and I have never had it before. However, sometimes my monitor *will* properly shut off from the lock screen. When that happens, the monitor will not turn on again if I move the mouse or type on the keyboard--I have to physically power the monitor off and then back on for it to show anything. Operating System: Arch Linux KDE Plasma Version: 6.4.1 KDE Frameworks Version: 6.15.0 Qt Version: 6.9.1 Kernel Version: 6.15.3-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 5700G with Radeon Graphics Memory: 32 GiB of RAM (30.7 GiB usable) Graphics Processor: AMD Radeon Graphics Product Name: B550M Pro4 My monitor is connected through HDMI. I use Wayland, but this bug also happens for me with the X11 session.
This sounds very similar to bug 493974, with the other bug is for displays waking after invoking sleep It may also be related to bug 505033, where displays are put to sleep with a keyboard shortcut and wake back up
I don't think so, this initial report is not related to sleep functionality, only the turn off of the monitor on the locked screen using escape key or with the option (In reply to TraceyC from comment #4) > This sounds very similar to bug 493974, with the other bug is for displays > waking after invoking sleep > It may also be related to bug 505033, where displays are put to sleep with a > keyboard shortcut and wake back up I think they are different, I have no issues with the sleep functionality, it is only with the screen being unable to turn off on the lock screen while the system is still running
(In reply to TraceyC from comment #4) > This sounds very similar to bug 493974, with the other bug is for displays > waking after invoking sleep > It may also be related to bug 505033, where displays are put to sleep with a > keyboard shortcut and wake back up I don't use sleep, but this may be related to bug 505033 as that also happens for me. This is similar to bug 348082, but unlike that bug my monitor always consistently turns back on after only a couple of seconds and does not turn off again.
The X11 side will likely never be fixed, see 457726
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/7868
Git commit e177e1d2da8a278f85d5d3e24ffdc01e7c2eaca6 by Xaver Hugl. Committed on 04/07/2025 at 13:10. Pushed by zamundaaa into branch 'master'. backends/drm: don't use UUID to identify outputs The UUID is only set later by the output configuration system, so it can't be used in the drm backend when deciding the dpms state of a "new" output. This changes it to use EDID ID, EDID hash or connector name instead, which are valid much earlier and are reliable enough for the dpms workaround. Related: bug 493879, bug 506135 M +19 -3 src/backends/drm/drm_backend.cpp https://invent.kde.org/plasma/kwin/-/commit/e177e1d2da8a278f85d5d3e24ffdc01e7c2eaca6
Git commit 8f331a268cf1e457b8727080763869e1b426dae8 by Xaver Hugl, on behalf of Xaver Hugl. Committed on 04/07/2025 at 13:57. Pushed by zamundaaa into branch 'Plasma/6.4'. backends/drm: don't use UUID to identify outputs The UUID is only set later by the output configuration system, so it can't be used in the drm backend when deciding the dpms state of a "new" output. This changes it to use EDID ID, EDID hash or connector name instead, which are valid much earlier and are reliable enough for the dpms workaround. Related: bug 493879, bug 506135 (cherry picked from commit e177e1d2da8a278f85d5d3e24ffdc01e7c2eaca6) Co-authored-by: Xaver Hugl <xaver.hugl@kde.org> M +19 -3 src/backends/drm/drm_backend.cpp https://invent.kde.org/plasma/kwin/-/commit/8f331a268cf1e457b8727080763869e1b426dae8