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Subject: Re: [PATCH 1/6] arm64: Unconditionally call unflatten_device_tree()
From: Stephen Boyd <sboyd@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>, linux-kernel@vger.kernel.org, patches@lists.linux.dev, linux-um@lists.infradead.org, linux-arm-kernel@lists.infradead.org, kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, devicetree@vger.kernel.org, Frank Rowand <frowand.list@gmail.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
To: Mark Rutland <mark.rutland@arm.com>
Date: Tue, 16 Jan 2024 17:27:18 -0800
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Quoting Mark Rutland (2024-01-16 03:51:14)
> Hi Stephen,
>=20
> On Fri, Jan 12, 2024 at 12:07:44PM -0800, Stephen Boyd wrote:
> > Call this function unconditionally so that we can populate an empty DTB
> > on platforms that don't boot with a firmware provided or builtin DTB.
> > There's no harm in calling unflatten_device_tree() unconditionally.
>=20
> For better or worse, that's not true: there are systems the provide both =
a DTB
> *and* ACPI tables, and we must not consume both at the same time as those=
 can
> clash and cause all sorts of problems. In addition, we don't want people =
being
> "clever" and describing disparate portions of their system in ACPI and DT.
>=20
> It is a very deliberate choice to not unflatten the DTB when ACPI is in u=
se,
> and I don't think we want to reopen this can of worms.

Hmm ok. I missed this part. Can we knock out the initial_boot_params in
this case so that we don't unflatten a DTB when ACPI is in use?