[$] Removing support for old hardware from the kernel
The kernel supports a wide range of hardware. Or, at least, the kernel
contains drivers for a lot of hardware, but the hardware for which many of
those drivers was written is old and, perhaps, no longer in actual use.
Some of those drivers would certainly no longer work even if the hardware
could be
found. These drivers provide no value, but they are still an ongoing
maintenance burden; it would be better to simply remove them from the
kernel. But identifying which drivers can go is not as easy as one might
think. Arnd Bergmann led an inconclusive session on this topic at the 2018
Kernel Maintainers Summit.