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Re: use of an intermediate device to handle USB interfaces

On Thu, 7 Feb 2008, Matthias Drochner wrote:

mouse%Rodents.Montreal.QC.CA@localhost said:
I recently did an install on a fairly vanilla server system.  I
counted nine PCI busses in the autoconf output - and at least one
bridge for each one.  The machine had only one physical PCI bus
(connectors &c) as far as I could tell.

My laptop has six of them and not a single PCI slot...
This is PCIexpress where everything is point-to-point.
(This could be made use of for power management, but
the gain of that would arguably be a small increment
compared to eg savings in the CPU.)

I'm not clear on the
difference between a device and an interface

A device is basically what plugs into a USB slot,
so eg link and power management is done at this level.
A device logically consists of (one or more) interfaces.
Interfaces often belong to some pre-defined interface
class which can be handled by some class driver.
Thus drivers for common stuff (storage, keyboards, audio...)
attach to some interface.

        So (assuming I've understood correctly), ucompound would
        map to a USB device and all NetBSD's existing usb devices
        would really be USB interfaces?

        As a (possibly somewhat insane idea), how would it work to
        merge ugen and ucompound - it could potentially allow people
        to poke at any device via the ugen interface at the cost
        of cluttering up the list of 'real' ugen devices...

                David/absolute       -- No hype required --

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