> I don't use any locators.  I'm not sure how thay can be used for USB.
> Each USB device is can be queried for a descriptor which contains
> a lot of information like vendor and product id, device class/subclass,
> revision etc.  I guess these could be locators, but I don't
> see the point.  It seems to work well without any locators.

What if I have multiple ostensibly "identical" (but not
interchangeable) devices plugged into the bus...  How do I nail down
the configuration so that the mapping from device-driver minor numbers
to physical devices remains the same?  even if I temporarily
plug/unplug yet another device?

Think of a monophonic speaker.  Assume I have two plugged in as my
`left' and `right' stereo channels.  if I just let the mapping
"float", what happens if I add a third speaker, and it happens to come
"before" the other two in the autoconfig order?  does the new one
become "left", the old "left" become "right" and the old "right" get
nothing at all?