I've finally managed to clean my Intel Graphics for Linux drivers following instructions at
http://theclonker.de/archive/89 (in my case I changed the origin of packages to wily, since I use 15.10)
then installing again the Displaylink driver, it was successful
however this solution wasn't optimal.. I noticed a decrease in battery performance and a bug in Google Chrome that forced me to disable the hardware acceleration there - this was fixed by installing the Intel drivers...