Earlier quoted context omitted.
Maybe they pull the stuff Nvidia does: write an interface kernel module, then have the driver itself in a library that the module loads. Since the actual driver is never part of the kernel tree...
It's much simpler. The OEM never releases the source. And courts have decided that it's not enough if you have some contributions to the kernel yourself or are a user to force them to release it, you have to have made significant contributions to force them to release it via the courts. And Torvalds and the major kernel maintainers all refuse to enforce the GPL, and actively campaign against doing so.
Two questions: why? and why use the GPL if you’re not going to enforce it?