Bug 461198

Summary: Wayland: Night Colour filter is restored incorrectly to reconnected display
Product: [Plasma] kwin Reporter: Manuel C <manuel.manu.delfin>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: kwin-bugs-null, nate, vlad.zahorodnii, xaver.hugl
Priority: NOR Keywords: wayland-only
Version First Reported In: 5.26.2   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Manuel C 2022-10-30 11:01:17 UTC 
SUMMARY
I recently switched from X11 to Wayland and found a regression with the Night Colour filter being applied incorrectly.

I run a multi-monitor setup, where I usually turn off my monitor at night (when Night Colour is active). When it is reconnected the next day (when Night Colour is off), the monitor still has the Night Colour filter active. This did not happen under X11.

To reset this state, I currently manually toggle Night Colour on and then back off.

I also tested the reverse, (disconnect while filter off, reconnect with it on) and it still happens. I assume there is just no check if the filter still applies when the display is reconnected.

STEPS TO REPRODUCE
1. Have 2 monitors
2. Turn on Night Colour
3. Disconnect, or disable the second monitor
4. Turn off Night Colour
5. Reconnect the monitor

OBSERVED RESULT
The reconnected display still has the blue light filter applied, while on the other one it is off

EXPECTED RESULT
The reconnected display has no blue light filter applied, like on the still connected display.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux, Kernel 6.0.5-arch1-1 (amd64)
KDE Plasma Version: 5.26.2
KDE Frameworks Version: 5.99.0
Qt Version: 5.15.6

ADDITIONAL INFORMATION
Graphics Platform: Wayland (1.21.0)
Comment 1 Zamundaaa 2023-10-27 21:28:26 UTC 
Is this still happening with 5.27.8 (or 5.27.9)? We fixed a bunch of night color related issues since your bug report
Comment 2 Bug Janitor Service 2023-11-11 03:45:48 UTC 
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 3 Manuel C 2023-11-14 17:16:57 UTC 
Sorry this took me a bit to come back to, with some testing it seems like this is no longer an issue on my end with Plasma 5.27.9.
I did encounter another oddity where several times I couldn't re-enable night light until restarting the desktop, after some amount of toggling it in the task bar. But I'll see if I can figure out a way to reproduce this reliably, and file another issue then :>