Bug 506297

Summary: Screen turns back on after locking on KDE Plasma under Wayland — powerdevil fails to turn off display, reports “no outputs”
Product: [Plasma] plasmashell Reporter: shervin_sa
Component: Power management & brightnessAssignee: Plasma Bugs List <plasma-bugs>
Status: RESOLVED DUPLICATE    
Severity: normal CC: kdedev
Priority: NOR    
Version First Reported In: 6.4.1   
Target Milestone: 1.0   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description shervin_sa 2025-06-28 00:36:54 UTC 
***
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***

SUMMARY


STEPS TO REPRODUCE
1.  Install latest EndeavourOS with KDE Plasma
2. Boot & log in
3. Lock the screen, or wait for screen to turn off due to set timer
4. Wait ( Screen goes blank, and then back on, stays on)

OBSERVED RESULT

After locking the session on KDE Plasma under Wayland (EndeavourOS, Arch-based), the monitor does not turn off. Logs show that powerdevil reports no outputs, and KWin cannot match display outputs, even though the monitor is still physically connected.

This issue occurs on a fresh install with no custom configurations.
EXPECTED RESULT
The screen should blank and turn off per the configured energy-saving settings.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:
KDE Plasma Version: 6.4.1
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1
OS: EndeavourOS (Arch-based)
Display Manager: SDDM
Display Server: Wayland
Kernel: 6.15.3-arch1-1


ADDITIONAL INFORMATION


Issue appears specific to Wayland (X11 not tested yet).
System is fully updated.
Occurs  with one monitor (HDMI)

This is happening my main machine, after the latest kde plasma update. I fresh installed onto an SSD to test if this was a problem with my config or not. Fresh install exhibits same behavior. All information provided is from a fresh install with no changes made. Just fully updated.  My main install is using Nvidia latest drivers. I even tried this with ddcutil turned off, same problem.  When the screen is supposed to turn off, it just goes blank for about 20 seconds (screen does not power down), and then back on again. 


System:
  Kernel: 6.15.3-arch1-1 arch: x86_64 bits: 64 compiler: gcc v: 15.1.1
    clocksource: tsc avail: hpet,acpi_pm
    parameters: initrd=\223235b7d2fa4c458d4ccfb7ff55c1c0\6.15.3-arch1-1\initrd
    nvme_load=YES nowatchdog rw
    root=UUID=9e148e8e-dce3-43e2-9f84-7324766c4fbf
    resume=UUID=0ed8302b-0942-4c58-85d9-6f6d0b2941cd nvidia_drm.modeset=1
    systemd.machine_id=223235b7d2fa4c458d4ccfb7ff55c1c0
  Desktop: KDE Plasma v: 6.4.1 tk: Qt v: N/A info: frameworks v: 6.15.0
    vt: 1 dm: SDDM Distro: EndeavourOS base: Arch Linux
Machine:
  Type: Desktop System: ASUS product: N/A v: N/A serial: <superuser required>
  Mobo: ASUSTeK model: ProArt B650-CREATOR v: Rev 1.xx
    serial: <superuser required> part-nu: SKU uuid: <superuser required>
    UEFI: American Megatrends v: 2506 date: 10/28/2024
Graphics:
  Device-1: NVIDIA AD102 [GeForce RTX 4090] vendor: Gigabyte driver: nvidia
    v: 575.64 alternate: nouveau,nvidia_drm non-free: 550-570.xx+
    status: current (as of 2025-04) arch: Lovelace code: AD1xx
    process: TSMC n4 (5nm) built: 2022+ pcie: gen: 1 speed: 2.5 GT/s lanes: 16
    link-max: gen: 4 speed: 16 GT/s ports: active: none empty: DP-1, DP-2,
    DP-3, HDMI-A-1 bus-ID: 01:00.0 chip-ID: 10de:2684 class-ID: 0300
  Device-2: Advanced Micro Devices [AMD/ATI] Raphael vendor: ASUSTeK
    driver: amdgpu v: kernel arch: RDNA-2 code: Navi-2x process: TSMC n7 (7nm)
    built: 2020-22 pcie: gen: 4 speed: 16 GT/s lanes: 16 ports:
    active: HDMI-A-2 empty: Writeback-1 bus-ID: 0c:00.0 chip-ID: 1002:164e
    class-ID: 0300 temp: 36.0 C
  Display: wayland server: X.org v: 1.21.1.18 with: Xwayland v: 24.1.8
    compositor: kwin_wayland driver: X: loaded: amdgpu,nvidia
    unloaded: modesetting alternate: fbdev,nouveau,nv,vesa dri: radeonsi
    gpu: amdgpu display-ID: 0
  Monitor-1: HDMI-A-2 model: Gigabyte AORUS FO48U serial: <filter>
    built: 2022 res: mode: 3840x2160 hz: 120 scale: 100% (1) dpi: 163 gamma: 1.2
    size: 941x529mm (37.05x20.83") diag: 690mm (27.2") ratio: 16:9 modes:
    max: 3840x2160 min: 640x480
  API: EGL v: 1.5 hw: drv: nvidia drv: amd radeonsi platforms: device: 0
    drv: nvidia device: 1 drv: radeonsi device: 3 drv: swrast gbm:
    drv: kms_swrast surfaceless: drv: nvidia wayland: drv: radeonsi x11:
    drv: radeonsi inactive: device-2
  API: OpenGL v: 4.6.0 compat-v: 4.5 vendor: mesa v: 25.1.4-arch1.1
    note: incomplete (EGL sourced) renderer: llvmpipe (LLVM 20.1.6 256 bits),
    AMD Radeon Graphics (radeonsi raphael_mendocino LLVM 20.1.6 DRM 3.63
    6.15.3-arch1-1), NVIDIA GeForce RTX 4090/PCIe/SSE2
  API: Vulkan v: 1.4.313 layers: 2 device: 0 type: discrete-gpu
    name: NVIDIA GeForce RTX 4090 driver: nvidia v: 575.64 device-ID: 10de:2684
    surfaces: N/A
  Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo
    de: kscreen-console,kscreen-doctor gpu: nvidia-smi wl: wayland-info
    x11: xdpyinfo, xprop, xrandr

Logs from journalctl from screen lock to unlock below.


---------------------------------
Jun 28 09:53:35 shervin-test kscreenlocker_greet[3536]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockOsd.qml:10:1: "../osd": no such directory
Jun 28 09:54:35 shervin-test dbus-broker[944]: A security policy denied :1.32 to send method call /org/freedesktop/login1/seat/seat0:org.freedesktop.login1.Seat.Inhibit to org.freedesktop.login1.
Jun 28 09:54:35 shervin-test kwin_wayland[1208]: kwin_core: Failed to delay sleep: Sender is not authorized to send message
Jun 28 09:54:50 shervin-test polkit-kde-authentication-agent-1[1502]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test kactivitymanagerd[1476]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test ksecretd[1177]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test python[1711]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test kdeconnectd[1712]: 2025-06-28T09:54:50 qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test konsole[3486]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test kwin_wayland[1208]: kwin_xwl: Could not find a matching X RandR CRTC/output to set as primary for KWin::PlaceholderOutput(0x55b439876040, name="Placeholder-1", geometry=QRect(0,0 1920x1080), scale=1)
Jun 28 09:54:50 shervin-test kscreenlocker_greet[3536]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test kwin_wayland[1208]: kwin_xwl: Could not find a matching X RandR CRTC/output to set as primary for KWin::PlaceholderOutput(0x55b439876040, name="Placeholder-1", geometry=QRect(0,0 1920x1080), scale=1)
Jun 28 09:54:50 shervin-test xdg-desktop-portal-kde[1504]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test plasmashell[1439]: kde.plasmashell: requesting unexisting screen available rect -1
Jun 28 09:54:50 shervin-test kded6[1392]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test org_kde_powerdevil[1503]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test plasmashell[1439]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:54:50 shervin-test plasmashell[1439]: kf.plasma.quick: Exposed with no visual parent. Window positioning broken.
Jun 28 09:54:51 shervin-test org_kde_powerdevil[1503]: [  1665] Removing connected display on bus 10
Jun 28 09:54:51 shervin-test org_kde_powerdevil[1503]: [  1665] (dw_remove_display_by_businfo) No Display_Ref found for i2c bus: 10
Jun 28 09:54:51 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:54:51 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:54:51 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:54:51 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:54:51 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:54:51 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:54:51 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:54:51 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:54:51 shervin-test kwin_wayland[1208]: kwin_xwl: Could not find a matching X RandR CRTC/output to set as primary for KWin::DrmOutput(0x55b439ed9610, name="HDMI-A-2", geometry=QRect(0,0 3840x2160), scale=1)
Jun 28 09:54:51 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:54:51 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:54:51 shervin-test kscreenlocker_greet[3536]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockOsd.qml:10:1: "../osd": no such directory
Jun 28 09:54:51 shervin-test org_kde_powerdevil[1503]: [  1665] Adding connected display with bus 10
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1665] Emitting DDCA_Display_Status_Event[282.883:  DDCA_EVENT_DISPLAY_CONNECTED, card1-HDMI-A-2, dref: DDCA_Display_Ref[2], io_path:/dev/i2c-10, ddc working: true]
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1665] libddcutil callback thread 0x7f6790016c30 started
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1665] Started 1 event callback thread(s)
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1503] Quiescing libddcutil API...
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1503] Quiesce libddcutil API complete
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1503] Display redetection starting.
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1664] recheck thread terminating because watch thread terminated
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1503] Watch thread terminated.
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(1) returned false and session type != X11. Assuming not asleep
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(2) returned false and session type != X11. Assuming not asleep
Jun 28 09:54:52 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(3) returned false and session type != X11. Assuming not asleep
Jun 28 09:54:53 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(4) returned false and session type != X11. Assuming not asleep
Jun 28 09:54:53 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(5) returned false and session type != X11. Assuming not asleep
Jun 28 09:54:53 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(6) returned false and session type != X11. Assuming not asleep
Jun 28 09:54:55 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier= 2.00, Testing for unsupported feature 0xdd returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO, DDCRC_DDC_DATA(9)]
Jun 28 09:54:55 shervin-test org_kde_powerdevil[1503]: [  1503] Turning off dynamic sleep and retrying
Jun 28 09:54:56 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier = 1.00, Retesting for unsupported feature 0xdd returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_DDC_DATA(10)]
Jun 28 09:54:58 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier= 2.00, Testing for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_DDC_DATA(10)]
Jun 28 09:54:58 shervin-test org_kde_powerdevil[1503]: [  1503] Turning off dynamic sleep and retrying
Jun 28 09:54:59 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier = 1.00, Retesting for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_DDC_DATA(10)]
Jun 28 09:55:01 shervin-test org_kde_powerdevil[1503]: [  1503] Watching for display connection changes, resolved watch mode = Watch_Mode_Xevent, poll loop interval = 100 millisec
Jun 28 09:55:01 shervin-test org_kde_powerdevil[1503]: [  1503]                                          extra_stabilization_millisec: 0,  stabilization_poll_millisec: 100
Jun 28 09:55:01 shervin-test org_kde_powerdevil[1503]: [  1503] libddcutil recheck thread (nil) started
Jun 28 09:55:01 shervin-test org_kde_powerdevil[1503]: [  1503] libddcutil watch thread 0x55a26894bcb0 started
Jun 28 09:55:01 shervin-test org_kde_powerdevil[1503]: [  1503] Display redetection finished.
Jun 28 09:55:01 shervin-test org_kde_powerdevil[1503]: [  1503] Unquiescing libddcutil API...
Jun 28 09:55:01 shervin-test org_kde_powerdevil[1503]: [  3653] (dw_recheck_displays_func) Recheck interval: Slept for 200 millisec
Jun 28 09:55:51 shervin-test dbus-broker[944]: A security policy denied :1.32 to send method call /org/freedesktop/login1/seat/seat0:org.freedesktop.login1.Seat.Inhibit to org.freedesktop.login1.
Jun 28 09:55:51 shervin-test kwin_wayland[1208]: kwin_core: Failed to delay sleep: Sender is not authorized to send message
Jun 28 09:56:06 shervin-test kactivitymanagerd[1476]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test ksecretd[1177]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test kdeconnectd[1712]: 2025-06-28T09:56:06 qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test python[1711]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test polkit-kde-authentication-agent-1[1502]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test kscreenlocker_greet[3536]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test kwin_wayland[1208]: kwin_xwl: Could not find a matching X RandR CRTC/output to set as primary for KWin::PlaceholderOutput(0x55b439c4f340, name="Placeholder-1", geometry=QRect(0,0 1920x1080), scale=1)
Jun 28 09:56:06 shervin-test kded6[1392]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test konsole[3486]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test kwin_wayland[1208]: kwin_xwl: Could not find a matching X RandR CRTC/output to set as primary for KWin::PlaceholderOutput(0x55b439c4f340, name="Placeholder-1", geometry=QRect(0,0 1920x1080), scale=1)
Jun 28 09:56:06 shervin-test xdg-desktop-portal-kde[1504]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test plasmashell[1439]: kde.plasmashell: requesting unexisting screen available rect -1
Jun 28 09:56:06 shervin-test org_kde_powerdevil[1503]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:06 shervin-test plasmashell[1439]: qt.qpa.wayland: There are no outputs - creating placeholder screen
Jun 28 09:56:07 shervin-test org_kde_powerdevil[1503]: [  3654] Removing connected display on bus 10
Jun 28 09:56:07 shervin-test org_kde_powerdevil[1503]: [  3654] Emitting DDCA_Display_Status_Event[357.229:  DDCA_EVENT_DISPLAY_DISCONNECTED, card1-HDMI-A-2, dref: DDCA_Display_Ref[3], io_path:/dev/i2c-10, ddc working: false]
Jun 28 09:56:07 shervin-test org_kde_powerdevil[1503]: [  3654] libddcutil callback thread 0x7f6798002ff0 started
Jun 28 09:56:07 shervin-test org_kde_powerdevil[1503]: [  3654] Started 1 event callback thread(s)
Jun 28 09:56:07 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:56:07 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:56:07 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:56:07 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:56:07 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:56:07 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:56:07 shervin-test kwin_wayland[1208]: kwin_xwl: Could not find a matching X RandR CRTC/output to set as primary for KWin::DrmOutput(0x55b439ed9610, name="HDMI-A-2", geometry=QRect(0,0 3840x2160), scale=1)
Jun 28 09:56:07 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:56:07 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:56:07 shervin-test kernel: HDR SB:aa 02 00 5f 84 c0 3e b0 33 cc 83 a8 1b ba 09 3a
Jun 28 09:56:07 shervin-test kernel: HDR SB:3d 47 40 be 01 de 00 be 01 be 01 00 00 00 00 00
Jun 28 09:56:07 shervin-test kscreenlocker_greet[3536]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockOsd.qml:10:1: "../osd": no such directory
Jun 28 09:56:07 shervin-test org_kde_powerdevil[1503]: [  3654] Adding connected display with bus 10
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  3654] Emitting DDCA_Display_Status_Event[359.298:  DDCA_EVENT_DISPLAY_CONNECTED, card1-HDMI-A-2, dref: DDCA_Display_Ref[4], io_path:/dev/i2c-10, ddc working: true]
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  3654] libddcutil callback thread 0x7f679801c270 started
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  3654] Started 1 event callback thread(s)
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] Quiescing libddcutil API...
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] Quiesce libddcutil API complete
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] Display redetection starting.
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  3653] recheck thread terminating because watch thread terminated
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] Watch thread terminated.
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(1) returned false and session type != X11. Assuming not asleep
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(2) returned false and session type != X11. Assuming not asleep
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(3) returned false and session type != X11. Assuming not asleep
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(4) returned false and session type != X11. Assuming not asleep
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(5) returned false and session type != X11. Assuming not asleep
Jun 28 09:56:09 shervin-test org_kde_powerdevil[1503]: [  1503] is_sysfs_reliable_for_busno(6) returned false and session type != X11. Assuming not asleep
Jun 28 09:56:11 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier= 2.00, Testing for unsupported feature 0xdd returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO, DDCRC_DDC_DATA(9)]
Jun 28 09:56:11 shervin-test org_kde_powerdevil[1503]: [  1503] Turning off dynamic sleep and retrying
Jun 28 09:56:12 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier = 1.00, Retesting for unsupported feature 0xdd returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_DDC_DATA(10)]
Jun 28 09:56:14 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier= 2.00, Testing for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_DDC_DATA(10)]
Jun 28 09:56:14 shervin-test org_kde_powerdevil[1503]: [  1503] Turning off dynamic sleep and retrying
Jun 28 09:56:16 shervin-test org_kde_powerdevil[1503]: [  1503] busno=10, sleep-multiplier = 1.00, Retesting for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_DDC_DATA(10)]
Jun 28 09:56:17 shervin-test org_kde_powerdevil[1503]: [  1503] Watching for display connection changes, resolved watch mode = Watch_Mode_Xevent, poll loop interval = 100 millisec
Jun 28 09:56:17 shervin-test org_kde_powerdevil[1503]: [  1503]                                          extra_stabilization_millisec: 0,  stabilization_poll_millisec: 100
Jun 28 09:56:17 shervin-test org_kde_powerdevil[1503]: [  1503] libddcutil recheck thread (nil) started
Jun 28 09:56:17 shervin-test org_kde_powerdevil[1503]: [  1503] libddcutil watch thread 0x55a2689175c0 started
Jun 28 09:56:17 shervin-test org_kde_powerdevil[1503]: [  1503] Display redetection finished.
Jun 28 09:56:17 shervin-test org_kde_powerdevil[1503]: [  1503] Unquiescing libddcutil API...
Jun 28 09:56:17 shervin-test org_kde_powerdevil[1503]: [  3719] (dw_recheck_displays_func) Recheck interval: Slept for 200 millisec
Jun 28 09:57:41 shervin-test kscreenlocker_greet[3536]: qt.qpa.wayland: Could not create EGL surface (EGL error 0x3000)
Jun 28 09:57:41 shervin-test kscreenlocker_greet[3536]: Failed to write to the pipe: Bad file descriptor.

-----------------------------------
Comment 1 TraceyC 2025-07-01 21:17:09 UTC 
The symptoms of this look the same as bug 493879, so I'm going to merge this bug into that older report.
I'll add the logging you provided, thank you for that useful detail.

*** This bug has been marked as a duplicate of bug 493879 ***