Login Loop on 17.10 and above (again)

[fthl]

Hi,

I by now have spent hours of fiddling and trying, all to no avail.
My DisplayLink works perfectly and very smooth up until 17.04 but in 17.10 and also 18.04 no matter what I do my Windows Manager seems to crash and sends me right back to the Login. Which was really weird seeing on a Live USB system ...
Now without the DisplayLink everything works fine.
What I've tried so far:

Pluggin in DisplayLink only after Login: I get thrown out to the Login Manager immediately
Different versions of Displaylink driver: Same issues on 4.2, 4.1, 4.0
The Modesetting/Pageflip workaround: That one actually does get the screen going, but the entire computer slows down to speeds that are utterly unusable (5 seconds plus for one mouse movement)
Different Versions of Ubuntu: 16.04, 17.04 work, 17.10, 18.04 not
Different flavours of Ubuntu: Same issues on Unity, Gnome3, Budgie, KDE and Cinnamon


17.04 went out of support months ago and 16.04 doesnt have that long left but due to this being my work vessel I kinda need those 2 screens.
By now I am really helpless on losing overview and would really appreciate and tips or guidance you can give!

Thanks in Advance!

[fthl]

Update: Apparently it DOES make a difference if its a live system or an installed one. In any case I have only been testing in live systems and now finally installed one.
On 18.04 it works so far.

[paml123]

Maybe change GPU (i hope nvidia) to CPU graphic card.