Bug 497287

Summary:	No external screen brightness control after suspend or hibernate
Product:	[Unmaintained] Powerdevil	Reporter:	sai <saipavanchitta1998>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	natalie_clarius, nate
Priority:	NOR
Version First Reported In:	6.2.4
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description sai 2024-12-10 18:00:13 UTC

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

Comment 1 sai 2024-12-10 18:02:59 UTC

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.

Comment 2 Nate Graham 2024-12-11 21:50:27 UTC


*** This bug has been marked as a duplicate of bug 482713 ***