UI Scaling in SDDM no longer works after KDE Plasma 6 upgrade

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1

Hello, after upgrading to KDE Plasma 6, SDDM no longer has a 200% UI scaling applied. Now that the sddm_kcm6 package is available, I tried pressing “apply plasma settings”, however, that didn’t fix the issue. Changing a theme seems to apply just fine, so it’s the UI scaling that is not working here.

I have a 2880x1800, 90Hz, 14 inch screen, so a 200% scaling is required for comfortable use. While this is a minor issue, I would rather have it working.

I have not made any manual changes to the SDDM config files, all settings are either the distro defaults or what the sddm_kcm package sets.

Here are the files:

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

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

[General]
HaltCommand=
RebootCommand=

[Theme]
Current=breeze-openSUSE
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

/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

[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

It seems like some dpi argument is indeed being passed to SDDM. However it’s under the X11 property. Not quite sure why. I’m using the wayland session of KDE Plasma.

Anyone knows what I can do to fix this?

2

No tinkering needed. A single line in the only configuration file works fine with Plasma:

erlangen:~ # cat /etc/sddm.conf
[General]
GreeterEnvironment=QT_SCREEN_SCALE_FACTORS=2,QT_FONT_DPI=192
erlangen:~ #

Screenshot_%Y%M%D_%H%m%S
Screenshot_%Y%M%D_%H%m%S1993×1492 132 KB

1 Like
3

Make a file called hidpi.conf

Put this in the file.

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

[Wayland]
EnableHiDPI=true

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

Put the file in /etc/sddm.conf.d/

4 Likes
4

I don’t have a sddm.conf file in the /etc directory. Which of the files I sent here should I modify?

5

Thank you! That worked.

1 Like
6

You’re welcome.

Also, at boot, when SDDM first comes up, the Breeze themes give me a nice big white cursor (mine is set to Oxygen White) and then it turns into a tiny black arrow. When you hit the button to log in you’ll see the big arrow again. I have a theme called Elarun and it works as expected so the problem is with the Breeze themes. I spent a lot of time on this and have not found the fix. I did find a bug about cursor size changing in SDDM but haven’t found a fix for Breeze themes.

1 Like
7

Yeah I noticed that too. It is a minor thing so I don’t mind. Probably will be fixed in time.

1 Like
8

man sddm.conf says:

NAME
sddm.conf - sddm display manager configuration

SYNOPSIS
Configuration loads all files in the configuration directories followed by the configuration file in the order listed below with the latter having highest precedence. Changes should be made to the local configurations.

   /usr/lib/sddm/sddm.conf.d
          System configuration directory

   /etc/sddm.conf.d
          Local configuration directory

   /etc/sddm.conf
          Local configuration file for compatibility

Don’t tinker with system directory. Always use the local one.

1 Like
9

Thanks for the tip jsmith64. I was wondering if a number other than 192 could be used, as my display scale is set a 175% instead of 200% like the OP.

10

Yes. You can change the 192 DPI to multiples of 32.
192 divided by 32 = 6

If you want smaller then use 5x32 (160), and for larger use 7x32 (224) etc.

11

Hi,

this is just for info.

After updating today booting was only possible into iceWM.

So deleted sddm and sddm_kcm6.
and re-installed kcm_sddm, there-after, all back to as it was.

conclusion: sddm_kcm6 is not ready for the new environment.

This worked without problems on another laptop.

12

oops.

updated this evening on other laptops and updated successfully!

ignore the prior message unless problems arise.

cheers

1 Like
13

It worked for me like charm. Thank you :slightly_smiling_face:

2 Likes
14

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