There are some issues with 11.2 and NVidia. Firstly, it has to be installed from ports for the moment, not packages.
Depending upon your card, you'll either want x11/nvidia-driver or, if it's an older card (you have to hunt around if it's a card that uses the legacy driver--NVidia has a list, but the model numbers sometimes differ, so you may have to look) use the nvidia-driver-340. If it's the 340, then in /boot/loader.conf you put nvidia_load="YES" if it's the newer driver then
nvidia_modeset_load="YES"
If X won't start, at this point, you can try running the nvidia-xconfig program which usually gives you a working xorg.conf that will work with your card. If it still won't start, the only time that this has happened to me was because there was no BusID entry in the xorg.conf created nvidia-xconfig, so look for a BusID line and if not, you'll have to add it.
To get the BusID, you can use nvidia-smi -q |grep Bus and you might get something like
Code:
Bus Id : 00000000:01:00.0
So you would put in /etc/X11/xorg.conf
in the Device section.
But sometimes, you don't even need an xorg.conf. I've never really noticed a pattern, and even if you do, you could cut out a lot of what nvidia-xconfig puts in there and get by with a few lines, but I've never cared enough, I fear, to see how much I can leave out.