Bug 433833

Summary: Wrong resolution detected for display results in multi-monitor misalignment
Product: [Applications] systemsettings Reporter: David Guaraglia <dguaraglia>
Component: kcm_kscreenAssignee: kscreen-bugs-null <kscreen-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: dguaraglia, nate, plasma-bugs-null
Priority: NOR    
Version First Reported In: 5.21.1   
Target Milestone: ---   
Platform: Manjaro   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: notice the discrepancy between the resolution combo box and the resolution in the layout editor

Description David Guaraglia 2021-03-02 05:23:16 UTC
Created attachment 136306 [details]
notice the discrepancy between the resolution combo box and the resolution in the layout editor

SUMMARY

The display resolution shown in the panel used to configure how screens are laid out is wrong. As you can see on the attached screenshot the resolution reported there is 1500x1000 but the actual screen resolution (displayed in the 'Resolution' combo box) is 3000x2000.

As far as I can tell this is not related to scaling, because when connecting a 4k external monitor the resolution for that monitor is shown properly on both the layout widget and the combo box. It's only the laptop's screen that seems to have this issue.

A corollary to this issue is that when I try to align both monitors as I used to in previous versions of Plasma, I have to pad the laptop monitor (which shows at half the size it should be) with a bunch of empty space to make up for the wrong resolution, otherwise there's an overlap between the external and the laptop's monitor (parts of a window will be present on both monitors as it gets close to the screen's edge).

STEPS TO REPRODUCE
1. Update to 5.21.1
2. Use the Display Configuration as usual


OBSERVED RESULT

Wrong resolution leads to wrong alignment in multi-monitor setup (it doesn't seem to cause any issues in a single monitor setup).

EXPECTED RESULT

Screen resolution should be correct and the size of the screen on the layout editor should be proportional to that size, rather than half the real size.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Manjaro Linux 20.2.1 (Nibia) / Kernel 5.11.1-1-MANJARO
KDE Plasma Version: 5.21.1
KDE Frameworks Version: 5.79.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION

Platform: X11
Comment 1 Nate Graham 2022-11-10 22:32:05 UTC
This should be fixed now as of Plasma 5.26, if not a few releases earlier.