Bug 487812 - I changed my brightness by mistake, the second screen is stuck on a wrong brightness value
Summary: I changed my brightness by mistake, the second screen is stuck on a wrong bri...
Status: RESOLVED FIXED
Alias: None
Product: Powerdevil
Classification: Plasma
Component: general (show other bugs)
Version: 6.0.4
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords: usability
Depends on:
Blocks:
 
Reported: 2024-05-30 19:41 UTC by V
Modified: 2024-08-25 21:33 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In: 6.2.0
Sentry Crash Report:


Attachments

Note You need to log in before you can comment on or make changes to this bug.
Description V 2024-05-30 19:41:25 UTC
SUMMARY
I scrolled by mistake on the brightness tray icon, messing up the brightness of my screens.
Now one of my 2 screens is stuck in an insanely bright mode, despite controlling the brightness cursor on the tray (apparently the only place where i can change that value), one screen changes, but not the other.

STEPS TO REPRODUCE
1. scroll by mistake like a moron on the tray icon
2. Brightness messed up
3. Enjoy the flashbang on the second screen for the rest of your life. :)

OBSERVED RESULT
Brightness not changing on the second screen.

EXPECTED RESULT
Brightness should change as it sometimes does on the second screen.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Void-Linux 6.9.2
KDE Plasma Version: 6.0.4
KDE Frameworks Version: 6.1.0
Qt Version: 6.6.0

ADDITIONAL INFORMATION
Nothing.
Comment 1 V 2024-05-30 19:42:34 UTC
Also specs:
CPU: R7 7800X3D
RAM: 32Gb
GPU: RX 7900 XTX
Driver: Mesa 24.0.7

and i run wayland.
Comment 2 ratijas 2024-06-14 09:49:04 UTC
In a Wayland session you can tweak brightness of the outputs individually using the kscreen-doctor CLI, it even has convenient Tab-completions. In an X11 session there is a utility called xbacklight.

So somehow the applet was able to change the brightness of one of your screens at first, but it immediately switched to controlling only the other screen, right? Was there anything suspicious going on in the system journal around the time when it happened?

Posting vendor/model numbers of your monitors might be valuable pieces of information here.

See also: https://notmart.org/blog/2023/02/how-to-report-multiscreen-bugs/
Comment 3 Jakob Petsovits 2024-08-23 19:39:39 UTC
Git commit 88aa87f7e6c291de02e6a585a04ccb0ebfcfd006 by Jakob Petsovits.
Committed on 23/08/2024 at 19:36.
Pushed by jpetso into branch 'master'.

applets/brightness: Per-display brightness controls

This uses the new per-display D-Bus API from PowerDevil.

Following this change, the applet does not use the old
BrightnessControl D-Bus interface anymore, only the new
ScreenBrightnessControl interface. A new ScreenBrightnessDisplayModel
class is added to allow the use of QML Repeater objects in the UI.

For scrolling on the icon, the applet does not need to know or
specify which displays are changed, this responsibility now lies with
the daemon and its AdjustBrightnessRatio/AdjustBrightnessSteps methods.

Autotests are adapted accordingly, including changes by Fushan Wen.
Note that reported brightness for the mocked backlight display will
be lower by 1 in the new API, because minimum brightness of 1
(default for internal displays) is subtracted from the underlying
brightness value. Hence we now test for values from 0 to 254.
Related: bug 431994, bug 481927, bug 353032

M  +15   -7    applets/brightness/package/contents/ui/BrightnessItem.qml
M  +0    -1    applets/brightness/package/contents/ui/CompactRepresentation.qml
M  +65   -40   applets/brightness/package/contents/ui/PopupDialog.qml
M  +44   -18   applets/brightness/package/contents/ui/main.qml
M  +1    -0    applets/brightness/plugin/CMakeLists.txt
M  +158  -53   applets/brightness/plugin/screenbrightnesscontrol.cpp
M  +39   -13   applets/brightness/plugin/screenbrightnesscontrol.h
A  +103  -0    applets/brightness/plugin/screenbrightnessdisplaymodel.cpp     [License: GPL(v2.0+)]
A  +49   -0    applets/brightness/plugin/screenbrightnessdisplaymodel.h     [License: GPL(v2.0+)]
M  +13   -4    autotests/applets/brightnesstest.py

https://invent.kde.org/plasma/powerdevil/-/commit/88aa87f7e6c291de02e6a585a04ccb0ebfcfd006
Comment 4 Jakob Petsovits 2024-08-25 21:33:23 UTC
Scrolling the brightness tray icon in Plasma 6.2 will affect the brightness of both your supported screens at once, but only relative to their previous respective brightness values. E.g. monitor 1 may go up from 80% to 85% while monitor 2 goes from 30% to 35%.

Previously, for two monitors it would apply the brightness value of monitor 1 to monitor 2 even if they had different value ranges altogether. This worked for most monitors, but didn't make sense in general and could conceivably break if one of both monitors doesn't use the usual 0 to 100 range.

Plasma 6.2 now also exposes brightness controls for each supported monitor so you can independently scale down the insanely bright monitor with its corresponding slider in the applet.

Feel free to reopen the bug if these changes don't end up fixing the described issue for you.