>> Point taken.  I'll try and get physical location as a locator
>> for USB.  A physical location will then be a sequence of 1-5
>> (there is a limit of hub depth to 5) port numbers that tells
>> you how to navigate from the root to the device.

In many environments these "locators' are _ABOSOLUTELY USELESS_, since
whoever builds the NetBSD kernel cannot stop people from changing the
devices.  Indeed the natural usage pattern may be that people *do*
change them.

Please make sure everything works if there is at most 1 of each device
class and all bus-topology locators are wildcarded.


>In the config file as:
>
>  usbroot* at pci?
>   usbhub* at usbroot?
>   usbhub* at usbhub?
>   usbdev* at usbhub?
>
>And if you need to nail things down more:
>
>  usbroot0 at pci?
>  usbhub0 at usbroot0
>  usbmonitor0 at usbhub0 port 0
>  usbhub1 at usbhub0 port 1
>  usbkeyboard0 at usbhub1 port 0
>  usbmouse0 at usbhub1 port 1
>  usbhub2 at usbhub1 port 2
>  usbaudio0 at usbhub2 port 0
>  usbaudio1 at usbhub2 port 1

Bill, these are *not* nailed down.  You can't driven nails into
sand;).  Maybe if you have the machine in a physically-secure space or
you can mandate "don't touch the USB", this counts as nailed down.
But that assumption doesn't hold everywhere.  

Designing long-lived kernel features around "nailed down" locators
that aren't in fact "nailed down" is just stupid.  A USB design that
*requires* these locators be specified (as the above seems to) is
Right Out.