quoted

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.

Exactly.  Note that such such an old parser will misparse
the "interrupt-array" property as well, namely, not at all.
Debugging *could* be a bit easier though, who knows.

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

That's not what those version fields are for.

The real solution is to just not use too old kernels with
too new a firmware/bootloader/device tree.  This issue
has existed for since forever and is in no way specific
to adding new OF bindings, or specific to Linux, or
anything like that.

It's more of a general problem.

Quite so.

It might be worthwhile to add a device tree property
"minimum-linux-version" (in the tree root) that the kernel
will parse and complain about loudly if it doesn't match;
at a minimum it will make it super-duper clear to users
of a DTS with that property which combos work.  Documentation
rules ;-)


Segher