SUMMARY After a fresh boot, I see the screen brightness control for both my internal laptop screen and the external screen. But when the screens turn off after inactivity, or I suspend or hibernate the machine and wake up - the external screen brightness is not to be seen in the applet on system tray. STEPS TO REPRODUCE 1. Suspend or wait to trigger screen off due to inactivity 2. Try to change external screen brightness through the applet on system tray Though, when I restart the powerdevil service with `systemctl --user restart plasma-powerdevil.service`, I see both the screen brightness options again. OBSERVED RESULT No external screen option in the screen brightness applet EXPECTED RESULT To change the external screen brightness SOFTWARE/OS VERSIONS Linux/KDE Plasma: 6.12.3-arch1-1 (64-bit) KDE Plasma Version: 6.2.4 KDE Frameworks Version: 6.8.0 Qt Version: 6.8.1
I forgot to add the logs: Here are the relevant system logs: ``` grep DDCutilDisplay Dec 10 11:36:49 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: ddca_open_display2 -3030 Dec 10 11:36:49 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: "HP 24mh" retrying to set DDC/CI brightness in 1000 milliseconds - attempt no. 1 Dec 10 11:36:50 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: ddca_open_display2 -3030 Dec 10 11:36:50 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: "HP 24mh" retrying to set DDC/CI brightness in 2000 milliseconds - attempt no. 2 Dec 10 11:36:52 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: ddca_open_display2 -3030 Dec 10 11:36:52 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: "HP 24mh" retrying to set DDC/CI brightness in 3000 milliseconds - attempt no. 3 Dec 10 11:36:55 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: ddca_open_display2 -3030 Dec 10 11:36:55 org_kde_powerdevil[867473]: org.kde.powerdevil: [DDCutilDisplay]: "HP 24mh" failed to set DDC/CI brightness ``` I found no relevant logs on the kernel buffer for the boot.
*** This bug has been marked as a duplicate of bug 482713 ***