Comment 6 for bug 1227214

Unity has no control over the kernel driver or the x.org driver used to support various hardware. If you choose to modify your system and configure it to use drives that do not support multi-touch input properly, you will get improper support for multi-touch in your system, but that is not a bug in individual applications like Unity.

The Wacom driver does not support the XInput 2.2 multi-touch protocol. Multi-touch on Ubuntu requires multi-touch support in the drivers.