Bug 494918

Summary:	Display remains dimmed after waking
Product:	[Plasma] plasmashell	Reporter:	luca-consoli
Component:	Power management & brightness	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	kde, kdedev, natalie_clarius, nate
Priority:	NOR
Version First Reported In:	6.2.1
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description luca-consoli 2024-10-17 09:50:37 UTC

SUMMARY
If you choose to change the screen brightness after some time and the screen powers off due to its timeout for saving power, when you move the mouse and the screen powers on again the brightness will not be restored at its original value, but it will remain at the percentage change you set.
Moreover, the brightness change seems to be applied only to the main screen and not on the other ones (my setup is a laptop with lid closed, connected to two HDMI external monitors). The second monitor only powers off at the specified interval.

STEPS TO REPRODUCE
1. Set the monitor brightness to be changed every n minutes
2. Set the monitor to power off every m minutes (m>=n)
3. Wait m minutes (i.e. wait for the screen to change brightness and also to power off)
4. Move the mouse or do something to power on the screen again

OBSERVED RESULT
The brightness stays at the percentage at which has been set after n minutes on the main monitor.

EXPECTED RESULT
The brightness returns at its default percentage after powering on the screen again and those changes should happen to the second monitor, too.
I would expect an option to disable those changes when external monitors are connected, too.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: 6.2.1
KDE Frameworks Version: 6.7.0
Qt Version: 6.8.0

ADDITIONAL INFORMATION

Comment 1 luca-consoli 2024-10-17 10:22:49 UTC

Disabling the brightness change, it seems that sometimes when you power on the screen after it has gone off for a while it has again the brightness lowered (even if it shouldn't change at all if the option is disabled).

Comment 2 TraceyC 2025-03-06 21:09:49 UTC

(In reply to luca-consoli from comment #1)
> Disabling the brightness change, it seems that sometimes when you power on
> the screen after it has gone off for a while it has again the brightness
> lowered (even if it shouldn't change at all if the option is disabled).

That sounds slightly different, and looks like bug 494497.

In this report, I'll focus on the original issue of the screen not returning to it's normal brightness after automatically dimming.
If this is still happening, can you paste the output of `kscreen-doctor -o`?

I wasn't able to reproduce this on git-master
I tested  with these settings in Power Management:
Change screen brightness: 60%
Dim automatically: 30 seconds
Turn off screen:  1 minute

1. Waited for 1 minute so the screen turned off
2. Moved the cursor to wake the screen

Result: the screen returned to 60% brightness

Comment 3 Bug Janitor Service 2025-03-21 03:46:58 UTC

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!

Comment 4 luca-consoli 2025-03-22 14:34:18 UTC

Hi, it seems that the bug is not appearing anymore with latest versions, so i think we can close this ticket for the moment.

Thanks.

Comment 5 Nate Graham 2025-03-22 15:51:01 UTC

Great, thanks!