Re: GPL only modules [was Re: [GIT PATCH] more Driver core patches for 2.6.19]

Posted Dec 15, 2006 14:29 UTC (Fri) by orospakr (guest, #40684)
Parent article: Re: GPL only modules [was Re: [GIT PATCH] more Driver core patches for 2.6.19]

From what I understand, the GPL considers something a derivative work if you either modify distribute a *changed* version of the work, OR you distribute something that links against the work's interfaces (#including header files, etc.).

nVidia wrote their driver in such a way as to avoid these restrictions (whether or not this is technically true is debatable, I suppose). The proprietary piece of their kernel module is wrapped entirely in Free Software code, and thus the proprietary piece does not derive directly from Linux itself. There's a technical reason for this, too: Linux will not load modules that weren't compiled against the *exact* same headers with the same gcc options, etc., so the Free Software piece provides a level of indirection for the kernel-agnostic proprietary piece. When faced with a kernel it has never seen before, the nvidia installer just compiles a new module provided the kernel api hasn't changed too much.

(The same thing applies to the Atheros HAL)

Do I have all that right?

Re: GPL only modules [was Re: [GIT PATCH] more Driver core patches for 2.6.19]

Posted Dec 22, 2006 2:44 UTC (Fri) by dwpfitzner (guest, #316) [Link]

No, as I understand it, the GPL does not define what is a derivative work -- copyright law does. Put another way: the GPL considers something a derivative work if it is a derivative work under copyright law. That is why there is a grey area: the definition of derivative work under copyright law is a grey area.

Eg, from GPL v2, section 0:

... a "work based on the Program" means either the Program or any derivative work under copyright law

Actually it goes on to say a bit more:

... a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term "modification".)

so it sort of includes a definition, but not being a lawyer I'm not sure how much weight the "that is to say" part has.