Re: GPL only modules

["D. Hazelton" <dhazelton@enter.net>]

On Sunday 17 December 2006 16:32, David Schwartz wrote:
> > I would argue that this is _particularly_ pertinent with regards to
> > Linux.  For example, if you look at many of our atomics or locking
> > operations a good number of them (depending on architecture and
> > version) are inline assembly that are directly output into the code
> > which uses them.  As a result any binary module which uses those
> > functions from the Linux headers is fairly directly a derivative work
> > of the GPL headers because it contains machine code translated
> > literally from GPLed assembly code found therein.  There are also a
> > fair number of large perhaps-wrongly inline functions of which the
> > use of any one would be likely to make the resulting binary
> > "derivative".
>
> That's not protectable expression under United States law. See Lexmark v.
> Static Controls and the analogous case of the TLP (ignore the DMCA stuff in
> that case, that's not relevant). If you want to make that kind of content
> protectable, you have to get it out of the header files.
>
> You cannot protect, by copyright, every reasonably practical way of
> performing a function. Only a patent can do that. If taking something is
> reasonably necessary to express a particular idea (and a Linux module for
> the ATI X850 card is an idea), then that something cannot be protected by
> copyright when it is used to express that idea. (Even if it would clearly
> be protectably expression in another context.)
>
> The premise of copyright is that there are millions of equally-good ways to
> express the same idea or perform the same function, and you creatively pick
> one, and that choice is protected. But if I'm developing a Linux module for
> a particular network card, choosing to use the Linux kernel header files is
> the only practical choice to perform that particular function. So their
> content is not protectable when used in that context. (If you make another
> way to do it, then the content becomes protectable in that context again.)
>
> IANAL.
>
> DS

Agreed. You missed the point. Since the Linux Kernel header files contain a 
chunk of the source code for the kernel in the form of the macros for locking 
et. al. then using the headers - including that code in your module - makes 
it a derivative work.

Actually, thinking about it, the way a Linux driver module works actually 
seems to make *ANY* driver a derivative work, because they are loaded into 
the kernels memory space and cannot function without having that done.

*IF* the "Usermode Driver" interface that is being worked on ever proves 
useful then, and only then, could you consider it *NOT* a derivative work. 
Because then the only thing it is using *IS* an interface, not complete 
chunks of the source as generated when the pre-processor finishes running 
through the file.

But as David said - IANAL

D. Hazelton