Can't change Background for Login Screen (SDDM) in systemsettings

English Install/Boot/Login
1

I want to change the background of the Login Screen.
Therefore I open systemsettings → Startup and Shutdown → Login Screen (SDDM)).
I select ‘Breeze for openSUSE’ and click on the landscape icon.
Sometimes it takes about 2-4 minutes until the next window appears where I can select ‘Load From File’ to change the background image.
Sometimes I interrupt the action after several minutes (>3) and get an incomplete Window where ‘Load From File’ and ‘Clear Image’ are missing.
It is noticeable that the CPU is heavily loaded during the waiting time.

Some observations that can help detect the problem:

  • The behavior is the same for a completely new user.
  • Clearing the directory ~/.cache/systemsettings/qmlcache does not change anything.
  • At my other (older) PCs this action shows no noticeable delay.
  • The current (problematic) one is also an Intel PC but with ‘Ultra 5 225’ CPU

I’m not able to compare EVERY setup switch between the current PC and any of my other ones. There are too many switches.

How can I find the cause of this behavior?

Regards Rolf

###########
System Info:
Opensuse leap 15.6 with updates until 2025-06-04
CPU Intel Ultra 5 255
RAM 16 GB
Motherboard ASUS H810M-CSM
Kernel 6.4.0-150600.23.50-default
KDE, Plasma5, X11

Output of [journalctl -b0 -S “2025-06-04 19:50:00” -U “2025-06-04 19:55:00”]: https://paste.opensuse.org/pastes/07ff63ed0d1d
Output of sar -u: [https://paste.opensuse.org/pastes/162a4025f64e](https://
paste.opensuse.org/pastes/162a4025f64e)
Output of sar -d: https://paste.opensuse.org/pastes/cfe99fdbb067
sadc raw data: too large; ask for details

2

Which version of KDE are you using? The default version included with Leap, or are you subscribed to the KDE repos?
https://en.opensuse.org/SDB:KDE_repositories
Show the results from kinfo

As user, watch the journal while you attempt the SDDM background image change process. Anything telling reported there?
journalctl -f

3

Apart from the issue you describe above (which I don’t observe), a possible workaround may be to modify /usr/share/sddm/themes/breeze/theme.conf.user manually, (changing the ‘background=’ entry as required).

4

I don’t use any special KDE repository at non of my PCs.

rolf@tw2l6:/home/rolf > zypper lr -u
Repository priorities in effect:                                                                 (See 'zypper lr -P' for details)
      99 (default priority) :  7 repositories
     100 (lowered priority) :  2 repositories

#  | Alias                                 | Name                          | Enabled | GPG Check | Refresh | URI
---+---------------------------------------+-------------------------------+---------+-----------+---------+-------------------------------------------------------------------------------------
 1 | Local_RPM                             | Local RPM                     | Yes     | ( p) Yes  | Yes     | dir:/usr/local/rpm
 2 | ftp.gwdg.de-openSUSE_Leap_$releasever | Packman Repository            | Yes     | (r ) Yes  | Yes     | http://ftp.gwdg.de/pub/linux/misc/packman/suse/openSUSE_Leap_15.6/
 3 | openSUSE-Leap-15.6-1                  | openSUSE-Leap-15.6-1          | No      | ----      | ----    | hd:/?device=/dev/disk/by-id/usb-Generic_Flash_Disk_N20C1700003567631424-0:0-part2
 4 | openSUSE:repo-non-oss                 | repo-non-oss (15.6)           | Yes     | (r ) Yes  | Yes     | http://cdn.opensuse.org/distribution/leap/15.6/repo/non-oss?mediahandler=curl2
 5 | openSUSE:repo-non-oss-debug           | repo-non-oss-debug (15.6)     | No      | ----      | ----    | http://cdn.opensuse.org/debug/distribution/leap/15.6/repo/non-oss?mediahandler=curl2
 6 | openSUSE:repo-openh264                | repo-openh264 (15.6)          | Yes     | (r ) Yes  | Yes     | http://codecs.opensuse.org/openh264/openSUSE_Leap?mediahandler=curl2
 7 | openSUSE:repo-oss                     | repo-oss (15.6)               | Yes     | (r ) Yes  | Yes     | http://cdn.opensuse.org/distribution/leap/15.6/repo/oss?mediahandler=curl2
 8 | openSUSE:repo-oss-debug               | repo-oss-debug (15.6)         | No      | ----      | ----    | http://cdn.opensuse.org/debug/distribution/leap/15.6/repo/oss?mediahandler=curl2
 9 | openSUSE:repo-oss-source              | repo-oss-source (15.6)        | No      | ----      | ----    | http://cdn.opensuse.org/source/distribution/leap/15.6/repo/oss?mediahandler=curl2
10 | openSUSE:update-backports             | update-backports (15.6)       | Yes     | (r ) Yes  | Yes     | http://cdn.opensuse.org/update/leap/15.6/backports?mediahandler=curl2
11 | openSUSE:update-backports-debug       | update-backports-debug (15.6) | No      | ----      | ----    | http://cdn.opensuse.org/update/leap/15.6/backports_debug?mediahandler=curl2
12 | openSUSE:update-non-oss               | update-non-oss (15.6)         | Yes     | (r ) Yes  | Yes     | http://cdn.opensuse.org/update/leap/15.6/non-oss?mediahandler=curl2
13 | openSUSE:update-non-oss-debug         | update-non-oss-debug (15.6)   | No      | ----      | ----    | http://cdn.opensuse.org/debug/update/leap/15.6/non-oss?mediahandler=curl2
14 | openSUSE:update-oss                   | update-oss (15.6)             | Yes     | (r ) Yes  | Yes     | http://cdn.opensuse.org/update/leap/15.6/oss?mediahandler=curl2
15 | openSUSE:update-oss-debug             | update-oss-debug (15.6)       | No      | ----      | ----    | http://cdn.opensuse.org/debug/update/leap/15.6/oss?mediahandler=curl2
16 | openSUSE:update-sle                   | update-sle (15.6)             | Yes     | (r ) Yes  | Yes     | http://cdn.opensuse.org/update/leap/15.6/sle?mediahandler=curl2
17 | openSUSE:update-sle-debug             | update-sle-debug (15.6)       | No      | ----      | ----    | http://cdn.opensuse.org/debug/update/leap/15.6/sle?mediahandler=curl2
rolf@tw2l6:/home/rolf > 

rolf@tw2l6:/home/rolf > kinfo
Operating System: openSUSE Leap 15.6
KDE Plasma Version: 5.27.11
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.12
Kernel Version: 6.4.0-150600.23.50-default (64-bit)
Graphics Platform: offscreen
Processors: 10 × Intel® Core™ Ultra 5 225
Memory: 15.0 GiB of RAM
Graphics Processor: llvmpipe
rolf@tw2l6:/home/rolf >

I did it.
See “Output of [jou…” above.

5

I too did not observe this issue at my other PCs as I wrote above.
I achieved the desired result by creating this file as you suggested:

rolf@tw2l6:/home/rolf > cat /usr/share/sddm/themes/breeze-openSUSE/theme.conf.user
[General]
background=stripes-red.png
type=image
rolf@tw2l6:/home/rolf >

But that does not solve the issue of high CPU usage and the significant delay.
I would like to solve the issue.

Any further tips?

6

Even though Plasma 5.27 is an LTS release, as Plasma 5 has effectively been superseded by Plasma 6, I personally wouldn’t expend to much time chasing the cause of the issue down. I have a Leap 15.6 host (running in a VM), but I use the latest KDE desktop environment with it.

If you wish to pursue this, there is some general debugging information that may be of value…
https://community.kde.org/KWin/Debugging

7

Thanks for your reply.
I’ll give it a try.

By the way, I found by chance a way to shorten the delay: activate the screen lock(Windows+L). But that is still not the solution.

8

Shouldn’t that contain the full path to the file?

9

Obviously not.
I checked it in my other PCs and copied it from there.
“systemsettings” copies the file from where I selected it into its own directory so it knows where to find. (/usr/share/sddm/themes/breeze-openSUSE/)