KDE Plasma Error

This is maybe a small problem, but I’ve been trying to install KDE Plasma as my DE. It’s just a matter of personal taste, nothing related to any project needs. I’m installing like I would in any Ubuntu install that came with another DE:

sudo apt install kubuntu-desktop

Set sddm instead of gdm3. Then I had issues with black screen on sddm. I tried to set gdm3 back and login into Plasma. The result was always an OpenGL2 error. I then added sddm user to video group. Now sddm works fine.

My problem now is Plasma itself, which stays black with the mouse moving. Supposedly were the shortcuts to Chromium and the forums are, I am able to right click and open them. But that’s about it. I tried ssh -X to open systemsettings5 from my other Linux machine and got this:

Application: System Settings (systemsettings5), signal: Aborted
Using host libthread_db library "/lib/aarch64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f7fe74010 (LWP 8936))]

Thread 4 (Thread 0x7f765ad130 (LWP 8941)):
#0  0x0000007f8388e04c in __GI___poll (fds=0x7f64003ce0, nfds=547641876324, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:41
#1  0x0000007f81ffde40 in ?? () from /usr/lib/aarch64-linux-gnu/libglib-2.0.so.0
#2  0x0000000000000001 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 3 (Thread 0x7f77e93130 (LWP 8940)):
#0  0x0000007f82046934 in g_mutex_lock () from /usr/lib/aarch64-linux-gnu/libglib-2.0.so.0
#1  0x0000007f81ffde24 in ?? () from /usr/lib/aarch64-linux-gnu/libglib-2.0.so.0
#2  0x0000000000000001 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 2 (Thread 0x7f7eb39130 (LWP 8939)):
#0  0x0000007f8388e04c in __GI___poll (fds=0x7f70004db0, nfds=547641876324, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:41
#1  0x0000007f81ffde40 in ?? () from /usr/lib/aarch64-linux-gnu/libglib-2.0.so.0
#2  0x0000000000000001 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 1 (Thread 0x7f7fe74010 (LWP 8936)):
#0  0x0000007f838692e0 in __GI___waitpid (pid=<optimized out>, stat_loc=0x0, options=<optimized out>) at ../sysdeps/unix/sysv/linux/waitpid.c:30
#1  0x0000007f85129cc8 in ?? () from /usr/lib/aarch64-linux-gnu/libKF5Crash.so.5
#2  0x0000007fe4bc90f8 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Any ideas?

Just adding that sudo apt-get install qt5-default and sudo apt-get install qt4-default as mentioned here did not solve the problem.

Edit: Forgot to mention that it did not solve the problem.

Make sure you are not using a Wayland based display manager with plasma , try setting your default display manager to kwin-x11. To use Wayland you need to enable the Jetsons drm kms driver which is only experimental.

X11 based desktop environment are only fully supported in the nano. When you log in make sure you are not starting a plasma-wayland session.

I am not using it:
Also I am not using sddm.

In /etc/gdm3/custom.conf
# Uncoment the line below to force the login screen to use Xorg
WaylandEnable=false

So its disabled.

How do I do this ? Where is this display manager callaed kwin-x11
Linux is freakingly complex…

I get a KDE error now as follows ( I now used lightdm).

Screenshot_20200922_171328_Cropped

Have you got KDE Plasma to work ? Could you please share what settings you have done. Thanks in advance…

Sorry for the late reply. No, I haven’t. I totally gave up on trying to make it work. :/

The same here. I thought : better not bother about such things on Linux :)