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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Patrick Mochel <mochel@osdl.org>
Cc: <linux-kernel@vger.kernel.org>, Jeff Garzik <jgarzik@mandrakesoft.com>
Subject: Re: [RFC] New Driver Model for 2.5
Date: Sat, 20 Oct 2001 01:30:26 +0200
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Reading about the suspend to disk issue, and thinking about
some of my needs, I tend to stil think we have overlooked
that issue. We should probably add a couple of list_heads
to define a second tree in parallell to the device-tree, which
is the power tree. A device is by default inserted in both
tree as a child of it's bus controller. But the arch must be
able to move it elsewhere. I beleive we have a way around the
VM related ordering issues, but we do have other kind of
ordering constraints. 

It may be me not reading well, but I think you didn't define
the fact that io_bus is a superset of device. In fact, it's
just a device that has childs, and this should probably be
more generically viewed in struct device itself. Any device
should be able to have childs, so we really have 2 interleaved
trees of devices, the bus tree and the power tree. In fact,
to be complete, we could even define the interrupt tree with
one more set of links as it's really not related to the bus
tree on many archs/machines, and having a tree definition
is really useful when you deal with cascaded controllers.

What do you think ?

Ben.


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