Thread (9 messages) flat view 9 messages, 2 authors, 2007-12-10

Re: [PATCH 2/3] Use embedded libfdt in the bootwrapper

From: David Gibson <hidden>
Date: 2007-12-10 23:32:25

On Mon, Dec 10, 2007 at 05:19:02PM -0600, Scott Wood wrote:
David Gibson wrote:
quoted
On Mon, Dec 10, 2007 at 11:32:17AM -0600, Scott Wood wrote:
quoted
How does using offsets as devps work if a devp was previously
acquired to a node that has to be moved due to a change later made
in an earlier part of the tree?
It doesn't; don't do that.  I just don't think truly persistent 
phandles are worth the code complexity to implement them.
We already have working code to implement them.  This is a regression 
over flatdevicetree.c, and it (or something else in libfdt) seems to be 
breaking the ep8248e wrapper (it didn't make it in to the last window 
because of dependency on a netdev patch, but I'll probably send it out 
tomorrow).

It breaks the extremely common and useful usage of:

devp = create node;
setprop(devp, "foo", something);
setprop(devp, "bar", something);
Uh.. no, that idiom is fine.  setprop() in the node itself, or any
descendent is guaranteed to be safe.
quoted
Especially since their use more-or-less completely precludes libfdt's
"stateless" approach, which has significant other advantages.
It doesn't preclude stateless read-only -- what are the benefits to 
stateless read-write that are worth invalidating all node references any 
time something changes?
It precludes stateless read-only too, unless you have an interface
where devps for read-write are different from those for read-only
which would be nasty.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson
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