FYI We are not supporting Genotoo package.
Then you should use newer x11-drivers/displaylink-driver that matches evdi-1.13 provided by Gentoo.
If it is not available you need to contact package maintainer.
Otherwise you can use .run installer afailable on displaylink download page:
https://www.synaptics.com/products/d...wnloads/ubuntu
There is something like "DisplayLink USB Graphics Software for Ubuntu" but it should work with Gentoo.