Dear fellow Slackware users,

I just upgraded a number of my machines from -current (around mid-October 2020) to the latest -current.
I carefully followed the package removals and additions, and so removed any packages that were removed since then, and installed almost all of the packages that were added since then.

I don't know whether there already are any open threads about similar problems but, my problems are the following:

• Earlier the login screen after X started was KDM, and for some reason it now reverted back to XDM. How could I change it back to KDM or something more aesthetic than XDM?
• After successfully logging in, I get returned to XDM, so I believe that KDE5 is not able to start for some reason. I have looked in Xorg.0.log, messages and syslog, but I couldn't find anything that would tell me what is wrong. Although I have to admit that I may not have been thorough enough.

Any help is appreciated.

Did you deal with all the *.new files that were dropped in /etc/ ? Their modifications are essential.

1 members found this post helpful.

KDM is gone with KDE4. So your choice would be sddm or xdm. If you got xdm, chances are you didn't install sddm.
Before you start in level mode 4, please log in in level 3 (console mode) as your user and run xwmconfig to select KDE5 as the default DE.

1 members found this post helpful.

Hi AlienBob,

I checked my /etc with find and even with slackpkg new-config but there were no stale .new files.

Hi gegechris99,

Thanks for the hints. KDE was selected as the default desktop environment.
After installing sddm, I ran a number of rounds with the error messages it presented (about missing dependencies*), but by now I eliminated them all, and SDDM starts up successfully, even the login seems to work, but KDE5 still won't start. Probably some additional dependency problems, but I can see no problem in /var/log/messages, /var/log/syslog or Xorg.0.log.

*: I don't understand, I colleted all removed and added packages from ChangeLog, but it still seems some were left out somehow...

Plus I just now stumbled on a new problem:

Console access doesn't seem to work: When I enter the username and press enter, I do not get the login prompt, the console just hangs for like 10 seconds, and a new login prompt is presented to me.
I believe it may be related to pam or elogind, but again I don't see any error messages in the usual places like messages and syslog.

It seems like I currently only have access to my machines via SSH :\

Most probably you still miss some mandatory dependencies. If you are using slackpkg to keep your system up to date, then I would suggest that you make a full installation as follows:
There have been many package additions and removals with the change of version of KDE and XFCE. Keeping track of them manually is error-prone.
After making sure that your system works with full installation, you can start removing those packages that you think are not needed by you. I know it's not an optimized way of working for you but we cannot help you further if we don't know if some mandatory packages are not installed.

1 members found this post helpful.

Could you check the ownership of your home folder ?
I had a weird change on an upgrade (that could be a local build) with a change to root owning a user folder.

Hi,

Thanks for the idea, but my home folder's ownership and access rights are okay.

I went through the steps you recommended and the console login issue seems to be solved.
On the other hand, KDE5 still doesn't start up properly for some reason. I get kicked back to the login screen.
I tried logging in on the console and starting X from there. That way X and KDE5 started up, but the KDE panel looked rather messed up, and only one display was active and in use. When I closed X, I saw no error messages on the text console.
The latter (only one display being active) also is true for the login screen.

Edited to add: by now it seems that I also have a nouveau bug/kernel driver traceback in dmesg with 5.10.4, but that does not seem to influence that I managed to get KDE5 running, when it is started from console, with startx.
If I try to log in via sddm, I still get kicked out right after login. So this seems to point somewhere other than KDE5.

On the bottom left of the sddm screen, you have a section: "Desktop Session". IIRC, the default is "Plasma (Wayland)". Make sure to change it to "Plasma".
Also you can catch some error in syslog files (run as root):
Regarding the messed-up panel, it could be due to some old KDE4 settings. When in console mode, I would suggest to back up your ~/.local and ~/.config directories and then delete them. Also it won't hurt to delete ~/.cache.

1 members found this post helpful.

Yes that seems to have been it. Plasma (Wayland) was selected by default, and when I selected Plasma, it worked on all my three machines.
I don't know exactly why wayland was a problem... I have installed it beforehand, but login did with Plasma (Wayland) being selected.

Yes, that's probably it, I will have to purge my old KDE4 settings, but that task will remain for another day.

Merci beaucoup for your help!