Currently you can configure "equalize" and it looks all fine and dandy.
The kernel has the interface defined, but apparently there's never actually
been any implementation for it (only a never merged patch in the 2.4 era).

I'm suggesting to drop the code to give any potential users of this feature
the benefit of receiving a proper error message. I see it unlikely that
this will be implemented in the near future, but if it ever happens
reviving the iproute2 side should be as easy as git revert this patch.

For more details see http://bugs.debian.org/149897