Ben Hutchings [off-list ref] writes:

[ Unknown signature status ]
On Mon, 2017-02-27 at 14:40 +0900, Masahiro Yamada wrote:

quoted

Since commit 6b22b3d1614a ("kbuild: Allow using host dtc instead of
kernel's copy"), it is possible to use an external dtc.=C2=A0=C2=A0In th=

is

quoted

case, we do not know which options are supported on it.
=20
Commit bc553986a2f7 ("dtc: turn off dtc unit address warnings by
default") gives -Wno-unit_address_vs_reg, but this options is only
recognized by v1.4.2 or later.
=20
If an older version is specified, the build fails:

But the option to use an external dtc was intended to allow testing of
newer versions.  If there's no reason to use this option to run an
older version, why bother trying to support that?

+1

That's a lot of added complexity, when the answer could just be "use the
kernel dtc".

cheers