[SOLVED] Ubuntu 21.10 + DisplayLink 5.6 - WORKING SOLUTION
 

I had a problem installing Display Link in a clean install of Ubuntu 21.10. And I solved the problem. Turn off wayland first.

sudo nano /etc/gdm3/custom.conf

and uncomment and set
WaylandEnable=false
sudo systemctl restart gdm3

Then install EVIDI/DKMS and then start installing DisplayLink Drivers. Finally, reboot and only then connect the USB 3.0 device. It will not work on USB 2.0.

sudo apt-get -y install evdi-dkms

Now

sudo reboot

Then download latest Ubuntu Drivers for DisplayLink.

Then extract this to the Desktop. Right click on the driver and properties... switch toggle to run this program.

Then run this program from command line sudo ./file_with_driver.run

After this reboot system once again and connect your DisplayLink on USB 3.0.

If you are previously installed EVIDI/DKMS or DisplayLink drivers remove everything EVIDI/DKMS and DisplayLink, then reboot system and install everything as I mentioned from the first step.