Subject: Re: towards loadable USB drivers
To: M. Warner Losh <>
From: Matthias Drochner <>
List: tech-kern
Date: 05/29/2005 18:16:45 said:
> This is a big can of worms.

Yes, assumptions about OS specific configuration are mixed with
hw specific stuff at many points. Perhaps we should improve
the abstractions first.

> you'll have to make sure that all the
> sub-interfaces are detached if Fred's match routine matches the whole
> device

...with the additional complication that the sub-interfaces
depend on a specific "configuration" of the device.
It would be cleaner if the "whole device" and the "configuration
dependant subdevice" were different interface attributes
(in terms of NetBSD autoconf).

> I'm likely, in FreeBSD, going to move to having the subdevs be
> in a logical container device

This would simplify the "detatch" a lot... And that
container device could also specify the USB "configuration".
(I don't have the impression that "configurations" are used
a lot, but it would look cleaner.)

> much like there's an extra layer in
> NetBSD for pccard and cardbus slots

Well, I've got the impression that autoconf device nodes are
used more generously than necessary in NetBSD... Would be
something to look at if I had too much time:-)

best regards