Date: Mon, 13 Nov 2000 22:46:19 -0800 From: Mike Smith <msmith@freebsd.org> To: Robert Lipe <robertlipe@usa.net> Cc: freebsd-hackers@freebsd.org Subject: Re: pci bus enumeration & cdevsw indexing Message-ID: <200011140646.eAE6kJF00794@mass.osd.bsdi.com> In-Reply-To: Your message of "Mon, 13 Nov 2000 09:02:17 CST." <20001113090217.Y20018@rjlhome.sco.com>
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> > > to avoid the hard-coded major numbers in the cdevsw[] entry that's
> > > passed? It seems like make_dev() should be able to roam cdevsw, find
> >
> > This is what devfs is meant to achieve. Unfortunately at the moment the
> > major numbers need to be fixed because there's no dynamism in /dev. If
>
> If you have devfs (and it means the same to you that it does to other
> OSes) that would solve the problem nicely. So is devfs something in
> 4.1.1 or is it future work? If it's here now, can you point me to an
> example? If it's future work, is that where I should be focusing?
It's a work-in-progress for 5.0 (on the -current branch), and yes, you
should most definitely be focussing there.
> For a UDI driver, that would be a problem. A UDI driver-writer has
> no clue where his target device will be running and, indeed, could be
> running on an OS without a /dev. So we could carve out a pool of b
> and c major numbers for UDI to then dynamically manage on behalf of
> the drivers, but that seems tedious. The environment has enough bread
> crumbs to know of a given driver is an HBA, a NIC, or something else and
> can set things up appropriately behind the scenes.
Realistically, the only things that still care about device major/minor
numbers are tty devices, control interfaces and non-SCSI non-ATA block
devices. Having said that, DEVFS is really the only sane answer here,
and it would probably be a prerequisite for anything like UDI.
Regards,
Mike
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
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