socketCAN vs OEM drivers
I emailed Kvaser about this and their answer was this:

"The Kvaser Drivers for Linux are not based on socketcan.  The Kvaser Linux driver is designed to match the CANlib SDK API we provide for the Windows platform.  This makes porting applications that use Kvaser hardware between Windows and Linux easier.

The socketcan support is a completely different driver that conforms to socketcan requirements and API.

Installing the Kvaser Linux driver will cause the Kvaser socketcan driver to be blacklisted.  We do not want both drivers trying to grab the same resource."

Hope this helps.