SUMMARY *** When the external monitor is set to turn off after a certain time of no activity, the brightness is not fully restored after wakeup. The brightness can be fixed with the the keyboard brightness buttons or with `ddcutil setvsp 10 + 65535`. *** STEPS TO REPRODUCE 1. run wayland session with dbus-run-session startplasma-wayland 2. set 'Screen energy savings' to 'Switch off after 3 min', press 'Apply' 3. wait 3 minutes until screen turns off 4. awaken screen by doing user input on keyboard OBSERVED RESULT The external monitor is on lowest brightness setting. EXPECTED RESULT The external monitor is on the same brightness as before it went to sleep. SOFTWARE/OS VERSIONS KDE Plasma Version: 5.24.3 KDE Frameworks Version: 5.91.0 Qt Version: 5.15.3 Linux Kernel: 5.15.30 Graphics platform: Wayland ADDITIONAL INFORMATION The graphics is embedded Intel graphics UHD Graphics 620. The monitor is LG connected via USB-C for display and power to the laptop. The laptop screen and the external monitor are active. Only the laptop monitor is restored to the initial brightness. Related bug: https://bugs.kde.org/show_bug.cgi?id=423457
The monitor is visible like this: ``` $ ddcutil detect Display 1 I2C bus: /dev/i2c-9 EDID synopsis: Mfg id: GSM Model: LG HDR 4K Product code: 30471 Serial number: Binary serial number: [..] Manufacture year: [..] VCP version: 2.1 ```
Same issue here, since powerdevil started depending on ddcutil (Arch Linux), every time my screen turns on after it was off for a while its brightness resets to zero but the value in the battery applet remains the same.
(In reply to Matej Mrenica from comment #2) > Same issue here, since powerdevil started depending on ddcutil (Arch Linux), > every time my screen turns on after it was off for a while its brightness > resets to zero but the value in the battery applet remains the same. In my case however, I only use one screen (desktop).
I have same issue with AMD GPU and 2 external displays (DP and HDMI). Those displays also happen to be only displays I have since it's desktop. However, for some reason brightness only gets reset to 0 only sometimes and it's not fully reproducible. Operating System: Arch Linux KDE Plasma Version: 5.27.7 KDE Frameworks Version: 5.108.0 Qt Version: 5.15.10 Kernel Version: 6.1.46-1-lts (64-bit) Graphics Platform: X11 Graphics Processor: AMD Radeon RX Vega M GL Graphics
*** Bug 486500 has been marked as a duplicate of this bug. ***
*** Bug 421492 has been marked as a duplicate of this bug. ***
*** Bug 423457 has been marked as a duplicate of this bug. ***
I collected various thoughts in this developer-focused issue titled "Dimming Rework": https://invent.kde.org/plasma/powerdevil/-/issues/38 I'm still not sure if specifically dimming-related bugs such as Bug 484129 or Bug 486500 (which was closed as duplicate of this one) are indeed the same thing as what you're seeing here, but I'm confident that the eventual fix will address all of these kinds of bugs at once.