Bug 461124

Summary:	Broken icons and fonts when using 2 monitors with different resolutions via integrated and discrete graphics card in Arch Linux, xorg
Product:	[Plasma] kwin	Reporter:	yekota2565
Component:	multi-screen	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	aleixpol, marteltheo, nate, notmart
Priority:	NOR	Keywords:	multiscreen
Version First Reported In:	5.26.0	Flags:	yekota2565: X11+
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description yekota2565 2022-10-28 16:46:25 UTC

SUMMARY
Broken icons and fonts when using 2 monitors via integrated and discrete graphics card. First monitor is plugged into VGA output of integrated graphics card, second monitor is plugged into VGA output of discrete graphics card. Before upgrading to plasma-desktop 5.26.0-1 in the BIOS was set to load first (and main) monitor, which is connected to the integrated video card, and the monitor, which is connected to the discrete load second. Before the upgrade everything was fine, after upgrading to this version broke icons and fonts: icons were not displayed, fonts in some places were static, their size did not change when you change the size in the settings, although it was visible that the size of the panels changes to the size of the font. The solution was found after I cleared the `.config`, `.cache` and `.local` folders. It turned out that for some reason, if the position of the smaller secondary monitor in the KDE display settings is aligned on top of the main larger monitor, all the icons disappear and stop rendering, and if aligned to the lower level of the main monitor, the icons appear back after reboot. But it doesn't fix the fonts. This behavior was fully corrected only after changing the order of monitors loading and setting the main monitor to a larger monitor connected to the discrete video card.

I am using Arch Linux, kernel 6.0.2 (it was the same on LTS), xorg, driver xf86-video-vesa.

STEPS TO REPRODUCE
1. If you use two monitors on different video cards (discrete and integrated), set the boot order so that the first and main monitor is the smaller monitor, which is connected to the integrated graphics card
2. In the KDE display settings, set the position of the first monitor to the top edge of the larger main monitor
3. reboot

OBSERVED RESULT
Icons will disappear, fonts will break.

EXPECTED RESULT
The same as before the upgrade to 5.26.0.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: ArchLinux, Linux kernel 6.0.2 and LTS, plasma-desktop 5.26.0-1 (The new version of KDE had the same problem)

Comment 1 Nate Graham 2022-10-28 20:14:56 UTC

Does it get better if you downgrade Mesa? There have heev a lot of graphical regessions caused by Mesa recently.

Comment 2 Martel Theo 2022-11-06 11:58:21 UTC

I have the exact same visual problem, with a slightly different configuration :

Laptop with one monitor on the iGPU, and an external monitor on the Nvidia dGPU (both same resolution), running latest Arch Linux.
When I launch the plasma session with both screen active, I don't have any icons on the desktop, and the font used for the Window title is changed (and any change using the Fonts menu in the system parameters app doesn't have any effect).
If I launch the plasma session with the external monitor unplugged, and only plug it afterwards, I keep the icons, but the font of all window titles immediately changes (and cannot be changed). The only relevant (?) line I could find in journalctl when I plug the external monitor is : ' kwin_x11[935]: Failed to compute left/right minimum bearings for "mtx" ' (mtx beeing the font that is forced used on the titles).

The problem appeared with the update to Plasma 5.26, Plasma 5.25.x was working correctly.

I tried downgrading Mesa to the version before (22.1.7, from mid-August), but I didn't change anything.