Re: [linux-usb] Re: USB device allocation

Brian Swetland (swetland@be.com)
Tue, 5 Oct 1999 17:26:07 -0700


[Dan Hollis <goemon@sasami.anime.net>]
> On Tue, 5 Oct 1999, Johannes Erdfelt wrote:
> > As it stands right now, there is no solution for naming of Plug and Play
> > devices. I'm specifically interested in USB since that's what I work on,
> > but this applies to everything plug and play (even PCMCIA)
> > The problem is if you have 2 mice, how do you name? What if they are
> > plugged in a different order, now 1 becomes 2 and 2 becomes 1.
>
> How do other OS deal with this issue? Eg BeOS Solaris M$doze etc?

Win98 definately seems to tie drivers to their topological position --
if I move a usb mouse from one port of a hub to another it installs
the driver again (requiring the CD). Bleagh.

BeOS doesn't offer an unified solution -- we do have a devfs (there are
no dev special files in our world) and devices are able to publish an
arbitrary list of names. The USB mouse/keyboard driver just publishes
/dev/input/mouse/usb/%d and /dev/input/keyboard/usb/%d, assigning numbers
on a first-come first-served basis.

Of course the input_server node monitors /dev/input/... and receives
a message when a new device is published and will then open it and
start listening to it (actually an input server add-on handles talking
to the device).

Brian

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