Subject: Re: [PATCH 15/16] Add device tree for Ebony

From: Segher Boessenkool <[email-masked]>
Date: Thu, 15 Feb 2007 03:43:05 +0100

>> Exactly.  The "separate device tree" imitates a real OF,
>> so you will lose much of its value if you start to deviate
>> from how real OF works.
>
> I disagree.  It was never (and isn't now) the intention to put all of
> the OF requirements on the device tree supplied on OF-less systems.

That's not my point; I'm saying that you shouldn't do the
same (or similar) things in different ways than "real OF"
does.

> In other words, "we should do X because the bindings require it" isn't
> of itself an argument for making X a requirement on the device tree.

It's a pretty strong indicator though; all other things
being equal, you should do what the bindings say.  There
can be good reasons to do differently, but then you better
have those reasons :-)

> "We should do X because there are good technical reasons for doing it
> that way" is.  "We should do X because if we don't then device trees
> from real OF systems won't be compatible" is also a reasonable
> argument.

You're turning the argument around, but hey :-)

> The device tree is required because it is a flexible way to give
> useful information to the kernel.  Thus the focus is quite properly on
> what is useful (or at least potentially useful) to the Linux kernel,
> not on what some binding document says.

Still, if you want to be compatible to "real OF" (and you
do, otherwise you would have chosen a structure that is
more appropriate for this goal), you better *be* compatible
to OF.

Segher