From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F245810E9; Wed, 17 Jan 2024 01:27:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705454841; cv=none; b=ssdnPpeIfg8yLfzVjOd6+y1tfY3aNXoCTd7w4kYNPteoJo6jF2vkXw2t0ISnDLqx0SvmsQ8sSi/8deelk8B+6I9+TRtuk6eNL0GpQfQiwk022Ivc1BG0NNbUACE7ZekOpnjowmblFJ1HIJfad3xOZKexJbZztR8NBKdLj4vCtBM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705454841; c=relaxed/simple; bh=u7BlLrJyg8NJtw6cjGr372yJi8HU88SzdYtGR597Yxg=; h=Received:DKIM-Signature:Message-ID:Content-Type:MIME-Version: Content-Transfer-Encoding:In-Reply-To:References:Subject:From:Cc: To:Date:User-Agent; b=txqydAxN3POfz9XoHsyLce6CL60GC5S5h2bnINv0+pKvZTL1IWo1VYrNAdOMHmMHtHhEGpHuxC7YH9FZShrt6fOrHfZ7i4NXQPraG8gHRBD8SvmNYPlMRlNn+EQUuHct2QgzRJE/KYoUN+IEt0EpAjdfybfF5F1Km3CPYV0Z+OA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tC9n+TgG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tC9n+TgG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5737EC433F1; Wed, 17 Jan 2024 01:27:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705454840; bh=u7BlLrJyg8NJtw6cjGr372yJi8HU88SzdYtGR597Yxg=; h=In-Reply-To:References:Subject:From:Cc:To:Date:From; b=tC9n+TgGzJdYa9eJaNIrd6YETp5ouaQa3aG/Bsb5/+N9Ozvs5fVcYmBG3R+99pSr5 6MQ+zqdLWmYJkkihzT5Ht0YQGPz5jNQVXsC52lwEWb6veqPJK0PgKqtIJWkAAsas2A ESvqojtCoN+ZsgPbnn0qdAQ83dvbZj1vzayHDMbAv4f8xzdUDnTPAV6JFSe5KGMIBP yO1jM5cRt4kuCl/+A2j/at9+4Kir3CEfkwNnX9m9EDx8HO8gBIGEM6Xd8aoajnN5sB GddFcKCgyWf5RXom2kEzyux5c/FbyuQ9jy3E+OHf8D8+0yBoSIBN3fGRnwpt7PN5gn NyOU6rMIxL3Kw== Message-ID: <434b21afe1899b1567f3617261594842.sboyd@kernel.org> Content-Type: text/plain; charset="utf-8" Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: References: <20240112200750.4062441-1-sboyd@kernel.org> <20240112200750.4062441-2-sboyd@kernel.org> Subject: Re: [PATCH 1/6] arm64: Unconditionally call unflatten_device_tree() From: Stephen Boyd Cc: Rob Herring , 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 , Catalin Marinas , Will Deacon To: Mark Rutland Date: Tue, 16 Jan 2024 17:27:18 -0800 User-Agent: alot/0.10 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?