RE: [RFC] powerpc: Document new property called interrupt-parents

-----Original Message-----
From: David Gibson [mailto:david@gibson.dropbear.id.au]=20
Sent: Tuesday, February 27, 2007 6:56 PM
To: Yoder Stuart-B08248
Cc: paulus@samba.org; linuxppc-dev@ozlabs.org
Subject: Re: [RFC] powerpc: Document new property called=20
interrupt-parents
=20
On Tue, Feb 27, 2007 at 04:54:45PM -0600, Stuart Yoder wrote:

quoted

=20
Document new property called interrupt-parents which can
be used to represent interrupts for devices that route
interrupts to more than one interrupt controller.

=20
Well, whatever Segher says, I'm still very concerned about the
potential for extra difficulty in debugging with this approach.

The issue, as I understand it, is the potential for an old
kernel parser to silently misparse a new dev tree with this
new property.

Do the version and last_comp_version in the blob header
help here?

If new dev trees with this new property were encoded with a
version=3D0x17 and last_comp_version=3D0x17 would the old
kernel parser error out if it only supported up to 0x16?

I'm not sure or not if that is the intended use of those
fields, but I think parser/DTS compatibility issues could
be solved by some kind of versioning.

It's more of a general problem.

Stuart