The proper use of EXPORT_SYMBOL_GPL()

A derived work is based on the base work. A clear and generally accepted indication that something is not a derived work is when the work can exist without the base work, or even clearer, if the work was created independently of the base work and is now only being integrated with the base work. If that is the case, then it's clearly not a derived work, but independent.

For example, a program originally created for BSD Unix is now being ported to Linux. (In addition to, and in line with, the special OS exception in GPL 2.0 clause 3,) that program is clearly not a derived work of Linux.

This reasoning does not apply to most device drivers, because they were written specifically for that kernel and typically even as part of the kernel. Most device drivers cannot exist independently of the OS they were written for, but inherently and deeply depend on it. Thus, it can be said that they are derived works.

The NVIDIA graphics driver was originally developed for Windows. It clearly existed and worked independent of its Linux adaption. From what I understand, large parts of the NVIDIA driver source code are shared between Windows, Linux and Mac. In fact, from what I read, the nVidia team made great efforts to keep as much code of the driver as possible generic and operating system independent.

Any code that depends on the OS and the API functions of the OS is therefore strictly necessary for its operation and optimal performance in terms of features and speed.

For me, that means that the nvidia driver is not a derivative work of the Linux kernel, for the same reason that a BSD Unix application is not a derivate of the Linux kernel. The technical details, that certain interfaces in Linux had to be created specifically to support the nvidia kernel, do not negate this fundamental situation from a legal point of view. That's similar to Linux adding e.g. new crypto interfaces in order to be able to run an already existing BSD application. Even if the BSD app needs additional APIs, the BSD app still existed and worked independent of Linux, just like the NVIDIA driver worked on Windows before it was integrated into Linux, and in fact it made efforts to use as little of the Linux kernel as technically reasonable, and therefore it cannot possibly be a derived work of Linux.

The phrase "any users of the functionality in question can only be a derived work of the kernel" is therefore false on face value.

Something that existed independently of the Linux kernel with the same feature on another OS and was merely ported from another OS to Linux can never be a derived work of the Linux kernel.

Ben