Created attachment 172002 [details] Brightness change SUMMARY Some sessions occur problem with changing screen brightness. First change(click on bar or scroll up/down on tray icon) works but then any attempts not working. In journal logs i can see: error setting brightness via dbus QDBusError("org.freedesktop.DBus.Error.UnknownObject", "No such object path '/org/kde/Solid/PowerManagement/Actions/BrightnessControl'") STEPS TO REPRODUCE 1. Change brightness 2. Again change brightness with failure SOFTWARE/OS VERSIONS Linux/KDE Plasma: openSUSE Tumbleweed (available in About System) KDE Plasma Version: 6.1.3 KDE Frameworks Version: 6.4.0 Qt Version: 6.7.2 ADDITIONAL INFORMATION AMD Graphic card: RX 6600XT Wayland session May be related i have 2 displays: - horizonal(primary) - vertical-right(secondary) Attached screen record
(In reply to Rafal from comment #0) > Some sessions occur problem with changing screen brightness. First > change(click on bar or scroll up/down on tray icon) works but then any > attempts not working. > In journal logs i can see: > error setting brightness via dbus > QDBusError("org.freedesktop.DBus.Error.UnknownObject", "No such object path '/org/kde/Solid/PowerManagement/Actions/BrightnessControl'") Thanks for the report and screen recording. If the BrightnessControl D-Bus interface is missing, I can think of two possible reasons: (a) PowerDevil crashed, which is unfortunately something that happens in 6.1.2 and 6.1.3 when waking up from inactivity and will only be fixed with 6.1.4. Have a look with `coredumpctl --reverse` to see if a powerdevil process recently produced a coredump after a crash. That would be Bug 490356. (b) ddcutil lost track of the monitor, so PowerDevil removed its brightness controls and the applet didn't recognize the disappearance of the BrightnessControl interface. That would be Bug 482713. Have a look with `ddcutil detect` whether your monitor is still recognized by ddcutil at all - it happened to me recently that this would stop working until a reboot.
(In reply to Rafal from comment #0) > Some sessions occur problem with changing screen brightness. First > change(click on bar or scroll up/down on tray icon) works but then any > attempts not working. Oh yeah, one more possible cause: (c) PowerDevil sends a brightness command to the monitor, but the command doesn't succeed so we remove it from the list of brightness controls. There was a recent MR at https://invent.kde.org/plasma/powerdevil/-/merge_requests/393 which improved this by delaying the command a little bit, that patch made it into 6.1.3. Given that your bug report is for 6.1.3, I'm guessing that the cause of your issue is a different one, but it's still possible that a permanently failing brightness write command will get the monitor removed from brightness controls. If this happens, you would see warning messages (likely about "ddca_set_non_table_vcp_value") in your system log, i.e. `journalctl -S today` for example.
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Tested with 6.1.4 today. The same behaviour after waking up session. (In reply to Jakob Petsovits from comment #1) > (In reply to Rafal from comment #0) > > Some sessions occur problem with changing screen brightness. First > > change(click on bar or scroll up/down on tray icon) works but then any > > attempts not working. > > In journal logs i can see: > > error setting brightness via dbus > > QDBusError("org.freedesktop.DBus.Error.UnknownObject", "No such object path '/org/kde/Solid/PowerManagement/Actions/BrightnessControl'") > > Thanks for the report and screen recording. If the BrightnessControl D-Bus > interface is missing, I can think of two possible reasons: > > (a) PowerDevil crashed, which is unfortunately something that happens in > 6.1.2 and 6.1.3 when waking up from inactivity and will only be fixed with > 6.1.4. Have a look with `coredumpctl --reverse` to see if a powerdevil > process recently produced a coredump after a crash. That would be Bug 490356. No recent powerdevil crashes. > (b) ddcutil lost track of the monitor, so PowerDevil removed its brightness > controls and the applet didn't recognize the disappearance of the > BrightnessControl interface. That would be Bug 482713. Have a look with > `ddcutil detect` whether your monitor is still recognized by ddcutil at all > - it happened to me recently that this would stop working until a reboot. seems like ddcutil still can comunicate Display 1 I2C bus: /dev/i2c-6 DRM connector: card1-DP-1 EDID synopsis: Mfg id: IVM - Iiyama North America Model: PLG2788H Product code: 26151 (0x6627) Serial number: 0 Binary serial number: 16843009 (0x01010101) Manufacture year: 2016, Week: 0 VCP version: 2.1 Display 2 I2C bus: /dev/i2c-8 DRM connector: card1-DP-3 EDID synopsis: Mfg id: IVM - Iiyama North America Model: PLG2488H Product code: 24871 (0x6127) Serial number: 0 Binary serial number: 16843009 (0x01010101) Manufacture year: 2016, Week: 0 DRM reports the monitor is in a DPMS sleep state (Off). DRM reports the monitor is disabled. DDC communication appears to work, but output is likely invalid. VCP version: 2.1 (In reply to Jakob Petsovits from comment #2) > (In reply to Rafal from comment #0) > > Some sessions occur problem with changing screen brightness. First > > change(click on bar or scroll up/down on tray icon) works but then any > > attempts not working. > > Oh yeah, one more possible cause: > > (c) PowerDevil sends a brightness command to the monitor, but the command > doesn't succeed so we remove it from the list of brightness controls. There > was a recent MR at > https://invent.kde.org/plasma/powerdevil/-/merge_requests/393 which improved > this by delaying the command a little bit, that patch made it into 6.1.3. > Given that your bug report is for 6.1.3, I'm guessing that the cause of your > issue is a different one, but it's still possible that a permanently failing > brightness write command will get the monitor removed from brightness > controls. If this happens, you would see warning messages (likely about > "ddca_set_non_table_vcp_value") in your system log, i.e. `journalctl -S > today` for example. I do not see such thing. About ddc only > org_kde_powerdevil[2605]: org.kde.powerdevil: [DDCutilDisplay]: ddca_open_display2 -3030 after waking up probably. But it is just info log. There is more about pulseaudio but i do not think it may be related with this
Seems to be fixed in 6.2.0