Subject: Re: dynamic configuration (was Re: PR#4094)
To: Darren Reed <darrenr@reed.wattle.id.au>
From: Greywolf <greywolf@starwolf.com>
List: tech-kern
Date: 08/25/2000 23:24:19
On Sat, 26 Aug 2000, Darren Reed wrote:

# Something which concerns me w.r.t. adding autocnfiguration (at this
# stage) to NetBSD is what happens when drivers are loaded at different
# major numbers (different card order, extra device, etc).  Some sort of
# "devfs" is then required, unless certain drivers force themselves to
# load at specific entries, right ?

Or you have the /etc/name_to_major and /etc/driver_classes which
halp make up the mess that is Solaris dynamic kernel loading...

# Darren

Not that I'd be against dynamic kernel loading, mind you, since then
only the needed devices would be loaded at boot time (kind of like
a working LKM on steroids), but the overhead that I've seen as-
sociated with this scheme has proven to be pretty high, not
to mention that if you put in a new driver somewhere and somehow
rearrange the ordering of the major numbers, it can be a headache.
I'd like to see the drivers declare their own major numbers, possibly
maintaining a sparse numbering scheme.  It would match most closely
what we have today, except that the driver would declare its number
(and type) on load rather than having a big ?devsw[] compiled in.

...or would this just be too far off base?  (or is this hypocritically
like the mess I described Solaris to be?)

				--*greywolf;
--
BSD: For The Network Generation