To help users in solving problem about the displaylink, some tests could be done :
Code:
# lsmod | grep evdi
It must return some lines with evdi module
Code:
# dmesg | grep -i display
It must not return any error.
Finally these two command should display services as active
Code:
# systemctl status display-manager.service
# systemctl status displaylink.service
If all of these command are correct, your device should be correctly detected and usable.
;-)