on TW with KDE.
after some update in the recent weeks, my KDE brightness controls are now malfunctioning.
logs from journalctl -b | grep powerdevil
Mar 18 14:10:11 localhost.localdomain org_kde_powerdevil[3043]: Starting libddcutil. library built Not set at Not set. stdout_stderr_redirected=true
Mar 18 14:10:11 localhost.localdomain org_kde_powerdevil[3043]: Initializing libddcutil. ddcutil version: 2.2.5, shared library: /usr/lib64/libddcutil.so.5.4.1
Mar 18 14:10:11 localhost.localdomain org_kde_powerdevil[3043]: library built Not set at Not set. stdout_stderr_redirected=true
Mar 18 14:10:11 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] Options passed from client:
Mar 18 14:10:11 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] Applying combined libddcutil options:
Mar 18 14:10:12 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] busno=9, 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(10)]
Mar 18 14:10:12 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] Turning off dynamic sleep and retrying
Mar 18 14:10:13 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] busno=9, sleep-multiplier = 1.00, Retesting for unsupported feature 0xdd returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO(10)]
Mar 18 14:10:15 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] busno=9, sleep-multiplier= 2.00, Testing for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO(10)]
Mar 18 14:10:15 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] Turning off dynamic sleep and retrying
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] busno=9, sleep-multiplier = 1.00, Retesting for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO(10)]
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: Library initialization complete.
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: Watching for DPMS state changes unimplemented
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] Watching for DPMS state changes unimplemented
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] Watching for display connection changes, resolved watch mode = Watch_Mode_Udev, poll loop interval = 500 millisec
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] extra_stabilization_millisec: 0, stabilization_poll_millisec: 100
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] libddcutil recheck thread 0x56315cdc2c70 started
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: [ 3043] libddcutil watch thread 0x56315cdaac40 started
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: [ 3229] (dw_recheck_displays_func) Recheck interval: Sleeping for 200 milliseconds
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: org.kde.powerdevil.chargethresholdhelper.getthreshold failed "Charge thresholds are not supported by the kernel for this hardware"
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: org.kde.powerdevil.backlighthelper.brightness failed
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: Handle button events action could not check for screen configuration
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: org.kde.powerdevil.chargethresholdhelper.getthreshold failed "Charge thresholds are not supported by the kernel for this hardware"
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: Failed to register with host portal QDBusError("org.freedesktop.portal.Error.Failed", "Could not register app ID: App info not found for 'org.kde.org_kde_powerdevil'")
Mar 18 14:10:17 localhost.localdomain org_kde_powerdevil[3043]: Failed to register with host portal QDBusError("org.freedesktop.portal.Error.Failed", "Could not register app ID: Connection already associated with an application ID")
Mar 18 14:10:18 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:10:18 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: "Dell AW3423DW" retrying to set DDC/CI brightness in 1000 milliseconds - attempt no. 1
Mar 18 14:10:19 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:10:19 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: "Dell AW3423DW" retrying to set DDC/CI brightness in 2000 milliseconds - attempt no. 2
Mar 18 14:10:22 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:10:22 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: "Dell AW3423DW" retrying to set DDC/CI brightness in 3000 milliseconds - attempt no. 3
Mar 18 14:10:25 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:10:25 localhost.localdomain org_kde_powerdevil[3043]: [DDCutilDisplay]: "Dell AW3423DW" failed to set DDC/CI brightness
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:04 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:05 localhost.localdomain org_kde_powerdevil[3043]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:11:09 localhost.localdomain org_kde_powerdevil[7686]: Starting libddcutil. library built Not set at Not set. stdout_stderr_redirected=true
Mar 18 14:11:09 localhost.localdomain org_kde_powerdevil[7686]: Initializing libddcutil. ddcutil version: 2.2.5, shared library: /usr/lib64/libddcutil.so.5.4.1
Mar 18 14:11:09 localhost.localdomain org_kde_powerdevil[7686]: library built Not set at Not set. stdout_stderr_redirected=true
Mar 18 14:11:09 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] Options passed from client:
Mar 18 14:11:09 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] Applying combined libddcutil options:
Mar 18 14:11:10 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] busno=9, 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(10)]
Mar 18 14:11:10 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] Turning off dynamic sleep and retrying
Mar 18 14:11:11 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] busno=9, sleep-multiplier = 1.00, Retesting for unsupported feature 0xdd returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO(10)]
Mar 18 14:11:13 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] busno=9, sleep-multiplier= 2.00, Testing for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO(10)]
Mar 18 14:11:13 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] Turning off dynamic sleep and retrying
Mar 18 14:11:14 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] busno=9, sleep-multiplier = 1.00, Retesting for unsupported feature 0x41 returned Error_Info[DDCRC_RETRIES in ddc_write_read_with_retry, causes: DDCRC_READ_ALL_ZERO(10)]
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: Library initialization complete.
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: Watching for DPMS state changes unimplemented
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] Watching for DPMS state changes unimplemented
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] Watching for display connection changes, resolved watch mode = Watch_Mode_Udev, poll loop interval = 500 millisec
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] extra_stabilization_millisec: 0, stabilization_poll_millisec: 100
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] libddcutil recheck thread 0x5647f2d4e6e0 started
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: [ 7686] libddcutil watch thread 0x5647f2cb5ab0 started
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: [ 7786] (dw_recheck_displays_func) Recheck interval: Sleeping for 200 milliseconds
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: Failed to register with host portal QDBusError("org.freedesktop.portal.Error.Failed", "Could not register app ID: App info not found for 'org.kde.org_kde_powerdevil'")
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: org.kde.powerdevil.chargethresholdhelper.getthreshold failed "Charge thresholds are not supported by the kernel for this hardware"
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: org.kde.powerdevil.backlighthelper.brightness failed
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: Handle button events action could not check for screen configuration
Mar 18 14:11:15 localhost.localdomain org_kde_powerdevil[7686]: org.kde.powerdevil.chargethresholdhelper.getthreshold failed "Charge thresholds are not supported by the kernel for this hardware"
Mar 18 14:11:16 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:11:16 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: "Dell AW3423DW" retrying to set DDC/CI brightness in 1000 milliseconds - attempt no. 1
Mar 18 14:11:17 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:11:17 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: "Dell AW3423DW" retrying to set DDC/CI brightness in 2000 milliseconds - attempt no. 2
Mar 18 14:11:19 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:11:19 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: "Dell AW3423DW" retrying to set DDC/CI brightness in 3000 milliseconds - attempt no. 3
Mar 18 14:11:22 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: ddca_set_non_table_vcp_value -3023
Mar 18 14:11:22 localhost.localdomain org_kde_powerdevil[7686]: [DDCutilDisplay]: "Dell AW3423DW" failed to set DDC/CI brightness
Mar 18 14:12:15 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:16 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:17 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:17 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:23 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:23 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:23 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:23 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:23 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:23 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:23 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:24 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:24 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:24 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
Mar 18 14:12:25 localhost.localdomain org_kde_powerdevil[7686]: Adjust screen brightness step failed: no displays available to adjust
rarely, on a fresh boot, things will work as expected (i can change brightness from the kde system tray widget, either by opening it or scrolling over it). most boots it will not work (only nightlight is visible when opening the widget, the britghtness bar is gone), but by systemctl --user status plasma-powerdevil.service it will function like normal again. however, on some boots this doesnt work for whatever reason.
i can use ddcutil to set the brightness as a last resort