This is fairly self explanatory - ENOIOCTLCMD is an internal code outside
of the -1 to -511 range.  The correct return for an unknown ioctl is
-ENOTTY although some Linux devices return the incorrect -EINVAL result.
Patch-By: Alan Cox <alan@redhat.com>
OSDL Developer Certificate of Origin 1.0 included herein by reference
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>