Bug 1221523

Summary:	kcm_sddm package unable to set UI scaling in SDDM after upgrading to KDE Plasma 6
Product:	[openSUSE] openSUSE Tumbleweed	Reporter:	Michal Walach <misawalach00>
Component:	KDE Workspace (Plasma)	Assignee:	E-Mail List <opensuse-kde-bugs>
Status:	RESOLVED FIXED	QA Contact:	E-mail List <qa-bugs>
Severity:	Minor
Priority:	P5 - None	CC:	vkrevs
Version:	Current
Target Milestone:	---
Hardware:	x86-64
OS:	openSUSE Tumbleweed
Whiteboard:
Found By:	---	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description Michal Walach 2024-03-17 22:23:41 UTC

After upgrading to KDE Plasma 6, SDDM does not scale its UI to 200% on my laptop's HiDPI screen (2880x1800, 90Hz, 14 inches). I'm using the Wayland session of KDE Plasma. UI Scaling in the actual desktop seems to work without any issues.

Now that sddm_kcm6 is available, I tried pressing "apply plasma settings", however, unlike in KDE Plasma 5, this does not fix the issue anymore.

I have tried changing my SDDM theme and it correctly applied, so it's the UI scaling in particular that does not seem to be working.

Here is my SDDM configuration. I have not made any manual changes to the configuration files. This is what KDE Plasma 6 sets using the sddm_kcm6 package:

/usr/lib/sddm/sddm.conf.d/00-general.conf:

[XDisplay]
ServerPath=/usr/bin/X
SessionCommand=/usr/etc/X11/xdm/Xsession
DisplayCommand=/usr/etc/X11/xdm/Xsetup
# No effect in 0.20.0, might change in the future again
MinimumVT=7
# boo#1089932
EnableHiDPI=true

[Users]
# boo#979775
ReuseSession=true




/usr/lib/sddm/sddm.conf.d/10-plasma.conf

# No effect in 0.20.0, might change in the future again
MinimumVT=7
# boo#1089932
EnableHiDPI=true

[Users]
# boo#979775
ReuseSession=true
yorimirus@localhost:/usr/lib/sddm/sddm.conf.d> cat 10-plasma.conf
[General]
GreeterEnvironment=QT_WAYLAND_SHELL_INTEGRATION=layer-shell

[Theme]
Current=breeze
CursorTheme=breeze_cursors

[Wayland]
CompositorCommand=kwin_wayland --no-global-shortcuts --no-lockscreen --locale1




/usr/lib/sddm/sddm.conf.d/10-theme.conf

[Theme]
Current=breeze-openSUSE
CursorTheme=breeze_cursors




/usr/lib/sddm/sddm.conf.d/11-kwin_wayland.conf

[General]
GreeterEnvironment=QT_WAYLAND_SHELL_INTEGRATION=layer-shell

[Wayland]
# --locale1 was introduced in kwin 5.27
CompositorCommand=kwin_wayland --no-global-shortcuts --no-lockscreen --locale1



/usr/lib/sddm/sddm.conf.d/20-breeze-openSUSE.conf

[Theme]
Current=breeze-openSUSE




/etc/sddm.conf.d/kde_settings.conf

[Autologin]
Relogin=false
Session=default.desktop
User=

[General]
HaltCommand=
RebootCommand=

[Theme]
Current=breeze
CursorSize=
CursorTheme=breeze_cursors
Font=Noto Sans,10,-1,0,400,0,0,0,0,0,0,0,0,0,0,1

[Users]
MaximumUid=60000
MinimumUid=1000

[X11]
ServerArguments=-dpi 192



It seems like some DPI parameter is being set but SDDM ignores it.

Comment 1 Michal Walach 2024-03-18 16:17:31 UTC

I have managed to work around this issue by creating a file called hidpi.conf in the /etc/sddm.conf.d directory with this content:

[General]
GreeterEnvironment=QT_SCREEN_SCALE_FACTORS=2,QT_FONT_DPI=192

[Wayland]
EnableHiDPI=true

[X11]
EnableHiDPI=true
ServerArguments=-nolisten tcp -dpi 192

It seems like the problem isn't with SDDM but with the sddm-kcm6 package. After creating this file SDDM is properly scaled to 200%.

Comment 2 Michal Walach 2024-03-30 08:50:10 UTC

Fixed in 6.0.3: https://bugs.kde.org/show_bug.cgi?id=467039

Closing report.