Bug 477152 - Other monitor (via other input) dims while not actively connected in a multi system multi monitor set-up.
Summary: Other monitor (via other input) dims while not actively connected in a multi ...
Status: ASSIGNED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Power management & brightness (show other bugs)
Version: 6.2.4
Platform: Arch Linux Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-11-17 17:27 UTC by Bart C
Modified: 2024-12-18 21:41 UTC (History)
2 users (show)

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Description Bart C 2023-11-17 17:27:35 UTC
SUMMARY
Other monitor (active via other input) dims while not actively connected in a multi system multi monitor set-up.

System is not being used for a while and dims monitor 1.
As a result monitor 2 dims as well (even though it is not showing/connected to said system - but displaying another input).

STEPS TO REPRODUCE
Monitor 1 connected via DVI-D to 'desktop'.
Monitor 1 has no other inputs connected.

Monitor 2 connected via VGA to 'desktop'.
Monitor 2 connected via DisplayPort to docking station.

Monitor 1 is displaying DVI-D (so 'desktop').
Monitor 2 is displaying DisplayPort (so docking station).

Docking station is connected to a laptop.

Now wait until screen dims.

OBSERVED RESULT
'desktop' dims monitor 1 after not being used for a while (correct).
Monitor 2 dims as well (even though it is not showing/connected to desktop) (unexpected).

Waking up monitor 1 (by e.g. mouse activity on 'desktop') also wakes up (i.e. undims) monitor 2.

EXPECTED RESULT
Monitor 1 and monitor 2 are dimmed by their respective connected inputs (they listen to the device they are connected to).

SOFTWARE/OS VERSIONS
    Operating System: Arch Linux 
    KDE Plasma Version: 5.27.9
    KDE Frameworks Version: 5.112.0
    Qt Version: 5.15.11
    Kernel Version: 6.6.1-arch1-1 (64-bit)
    Graphics Platform: X11
    Processors: 4 × Intel® Core™ i5-4590 CPU @ 3.30GHz
    Memory: 15,5 GiB of RAM
    Graphics Processor: Mesa Intel® HD Graphics 4600
    Manufacturer: Gigabyte Technology Co., Ltd.
    Product Name: B85M-HD3

ADDITIONAL INFORMATION
* 2 monitors (2x Dell P2314H)
  Energy Smart is off, DDC/CI disabled, LCD conditioning enabled (on both)
* Dell docking station D6000 USB-C
* System (name 'desktop')
Comment 1 Jakob Petsovits 2024-08-27 08:46:38 UTC
This should be fixed with Plasma 6.2 on Wayland, because on Wayland we provide hardware brightness controls to KWin and then ask KWin to change brightness only for enabled screens. Thereby ignoring other hardware brightness controls that don't belong to an enabled KWin screen.

I don't currently have the hardware at hand to confirm that this is indeed fixed now, so let's leave this open until I or someone else can retest.

It may be possible to fix this also for X11, but would require additional work and is not high up on my priority list.
Comment 2 Bart C 2024-08-30 16:31:01 UTC
(In reply to Jakob Petsovits from comment #1)
> This should be fixed with Plasma 6.2 on Wayland, because on Wayland we
> provide hardware brightness controls to KWin and then ask KWin to change
> brightness only for enabled screens. Thereby ignoring other hardware
> brightness controls that don't belong to an enabled KWin screen.
> 
> I don't currently have the hardware at hand to confirm that this is indeed
> fixed now, so let's leave this open until I or someone else can retest.
> 
> It may be possible to fix this also for X11, but would require additional
> work and is not high up on my priority list.

Thank you for reminding me of this one - as I turned off the dimming after x time so not seeing this behavior and upgrading to KDE 6 I kind of forgot this one.

I'm currently on the software mentioned below (hardware hasn't changed except for the dock due to changing employer) and unfortunately I still see this behavior.

Operating System: Arch Linux 
KDE Plasma Version: 6.1.4
KDE Frameworks Version: 6.5.0
Qt Version: 6.7.2
Kernel Version: 6.10.6-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-4590 CPU @ 3.30GHz
Memory: 15,5 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 4600
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: B85M-HD3

ADDITIONAL INFORMATION
* Docking station Dell UD22