Bug 425192

Summary:	Screens overlap on Wayland when scaling is fractional
Product:	[Plasma] KScreen	Reporter:	Kyrylo Bohdanenko <kirill.bogdanenko>
Component:	common	Assignee:	kscreen-bugs-null <kscreen-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	kirill.bogdanenko, nate
Priority:	NOR
Version:	5.19.4
Target Milestone:	---
Platform:	Ubuntu
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Kyrylo Bohdanenko 2020-08-10 15:12:35 UTC

SUMMARY
I have a dual-monitor setup: a 4K (3840x2160) laptop 15.6" screen and a 1920x1200 external 24" monitor (Dell U2413).
Here is kscreen-console dump: https://invent.kde.org/snippets/1098

STEPS TO REPRODUCE
1. Log in to Wayland session
2. Set scaling to be fractional (e.g. 195% = 1.95) on one monitor
3. Connect external screen (leave it at 100% scaling)

OBSERVED RESULT
There is a slight overlapping of displays. E.g. when a window is moved to the side of the screen, which is adjacent to the other screen, a few pixels of the window (close to the screen edge) are also duplicated on the other screen. I.e. I can see the same pixels drawn twice.

And this cannot be remedied by moving display arrangement in the System Settings: as long as displays are adjacent there is the overlap.

EXPECTED RESULT
The displays should not overlap no matter the scaling.

SOFTWARE/OS VERSIONS
Linux: Kubuntu 20.04
KDE Plasma Version: 5.18.5 
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8

ADDITIONAL INFORMATION
This only happens on Wayland session.

Comment 1 Kyrylo Bohdanenko 2020-08-10 15:52:19 UTC

Update: this is still relevant with Kubuntu  20.10 (development branch) and KDE Plasma 5.19.4, KDE Frameworks 5.72.0 and Qt 5.14.2

Comment 2 Nate Graham 2022-11-08 21:15:21 UTC

Thank you for the bug report. Unfortunately we were not able to get to it yet. Can we ask you to please check if this is still an issue with Plasma 5.25 or 5.26?

If it is, please change the status to CONFIRMED when replying. If not, or if you can't because you no longer use this setup, you can change the status to RESOLVED WORKSFORME. Thanks a lot!

Comment 3 Kyrylo Bohdanenko 2022-11-09 02:11:49 UTC

Still relevant with Plasma 5.25.5 on Ubuntu 22.10.

I can work around the problem by dragging the scaled display and re-aligning (re-sticking) to the side of the non-scaled one. So the issue might be in the initial positioning when the re-scale is applied.

Comment 4 Nate Graham 2022-11-09 20:45:24 UTC

Thanks. I think it's Bug 455394.

*** This bug has been marked as a duplicate of bug 455394 ***