What brand/model/chipset?
lsusb
When you connect it, what is reported by dmesg?
dmesg|tail
FWIW, a very old (but interesting thread) on the subject…
https://forums.opensuse.org/showthread.php/480963-USB-to-DVI-DisplayLink-with-OpenSUSE-12-2-and-KDE-with-xrandr-KRandR