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Date: Tue, 05 Apr 2011 14:06:22 +0300
From: Andriy Gapon <avg@FreeBSD.org>
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Cc: Hans Petter Selasky <hselasky@FreeBSD.org>
Subject: Re: use_generic and usb probing
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on 03/04/2011 13:46 Andriy Gapon said the following:
> 
> Mostly out of curiosity (but not only because of that) I wonder why the
> use_generic flag and two probing passes are needed in USB driver probing code.
> That is, why the standard approach of using different probing return values
> (e.g. BUS_PROBE_DEFAULT, BUS_PROBE_GENERIC, etc) wouldn't work here.

I couldn't find any historic reason for this, so I am assuming that this is a
kludge to work-around inconsistent return values in various USB "newbus" probe
routines.

Please see here my attempt at cleaning up the basics:
http://people.freebsd.org/~avg/usb-use_generic.diff

Reviews and testing are welcome.

P.S.
A side-effect of this patch is removal of a minor annoyance in a form of the
following message:
Unknown USB device: vendor <> product <> bus <>
The message is produced by devd almost any time anything is connected via USB
thanks to (1) a nomatch USB entry in the default devd.conf; (2) use_generic=0
probing pass in USB.
-- 
Andriy Gapon