So using a kernel module for the closed source NVIDIA driver for Linux is a GPL violation?
As far as I understood, the GPL only applies for code that is directly linked to it. A call to an external library (e.g. a kernel module) wouldn't necessarily apply. The code is being delivered as separate binaries.
> So using a kernel module for the closed source NVIDIA driver for Linux is a GPL violation?
Yes. Your understanding isn't correct.
With NVIDIA, there's this complicated dance where you download source code from nVidia for the kernel module, then compile it on your own machine and use it -- you aren't violating copyright because you don't distribute the kernel module that you compiled for yourself on your own machine.
But that kernel module does indeed violate GPLv2, and you can't distribute it legally, and neither could Canonical or nVidia (which is why they do the dance above instead).
> "But that kernel module does indeed violate GPLv2, and you can't distribute it legally, and neither could Canonical or nVidia (which is why they do the dance above instead)."
If that's the case, then why doesn't the FSF sue Linux kernel developers over licence violations? There are clearly pre-compiled binary blobs distributed along with the mainline kernel (otherwise there would be no need for the Linux-libre project to exist: https://en.wikipedia.org/wiki/Linux-libre ). There's little point having a licence if there's no consequences for breaking it.
I suspect they don't because it's not a simple case, and that such a measure would be somewhat counterproductive for their cause.
> If that's the case, then why doesn't the FSF sue Linux kernel developers over licence violations?
I don't understand. The Linux kernel developers hold the copyright on the kernel. If someone sues someone else, it's them --- the kernel developers -- who have standing to be doing the suing. They didn't give their copyright to the FSF merely as a result of choosing to use the FSF's license.
So if none of the Linux kernel developers sues Canonical for using a OpenZFS kernel module, Canonical can carry on with it and nothing of value was lost.
This is true, but most companies would want better assurance of their work's legality than "well, as long as none of the tens of thousands of people we just gave grounds to sue us actually do so, we'll be fine".
As far as I understood, the GPL only applies for code that is directly linked to it. A call to an external library (e.g. a kernel module) wouldn't necessarily apply. The code is being delivered as separate binaries.