“Here’s one from the file of random stuff you see when you put a
new machine on the upstream kernel instead of the distro kernel.
USB drivers for Linux will be GPL-only with the release of the
upcoming kernel 2.6.25. USB maintainer Greg Kroah-Hartman writes:
‘Over two years ago, the Linux USB developers stated that they
believed there was no way to create a USB kernel driver that was
not under the GPL. This patch moves the USB apis to enforce that
decision.’“(The actual ‘enforce’ here is just copyright law: the GPL is
the only thing that allows you to distribute your ‘derivative work’
of Linux, and it only applies if you provide source…)”