From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 21D3FC4707B for ; Thu, 18 Jan 2024 15:27:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=kYd8rTZnPJafqQNO2ERks9WuhUJxX84hAlfuW0l/ftY=; b=t0Y7cvNgSSfWwU ZP3Cpea61E4wYFIOxaYew6a7eVgbLsT9kgIKhVksvKHEbJrk+dh2T1+i/0JqFTNMdLbmQkIq32De5 2AKW13hOrXUCtZuBhUEwEdZNN+b7IrECY+SOaHZBJ4xuReOqrG0Fw+HUIDYu0anTLRJ6LTTkY4ad2 xs24IILqf+sc4BjLWXhQOO0fDV6o0Qy/4TjbpEKyO2nnjpnMhF5bSVbcTMgjAAceqv9JiTorGy8Pl oD5jOTkhNtrWoXJzMXdImtTqgtiNFfsUi2emUl600tqUKeI3be2PUio4H/+tFf7FnpCqkhDXhDwKt aObi3EmA7Z20dRJw1ndQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rQUIB-00362N-1t; Thu, 18 Jan 2024 15:26:55 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rQUI8-00361b-1k; Thu, 18 Jan 2024 15:26:54 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2A8C11042; Thu, 18 Jan 2024 07:27:36 -0800 (PST) Received: from FVFF77S0Q05N.cambridge.arm.com (FVFF77S0Q05N.cambridge.arm.com [10.1.28.174]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 73C1F3F73F; Thu, 18 Jan 2024 07:26:47 -0800 (PST) Date: Thu, 18 Jan 2024 15:26:43 +0000 From: Mark Rutland To: 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 Subject: Re: [PATCH 1/6] arm64: Unconditionally call unflatten_device_tree() Message-ID: References: <20240112200750.4062441-1-sboyd@kernel.org> <20240112200750.4062441-2-sboyd@kernel.org> <434b21afe1899b1567f3617261594842.sboyd@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <434b21afe1899b1567f3617261594842.sboyd@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240118_072652_714153_94C1581F X-CRM114-Status: GOOD ( 18.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jan 16, 2024 at 05:27:18PM -0800, Stephen Boyd wrote: > Quoting Mark Rutland (2024-01-16 03:51:14) > > Hi Stephen, > > > > 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. > > > > 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. > > > > It is a very deliberate choice to not unflatten the DTB when ACPI is in use, > > 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? Why is that better than just not calling unflatten_device_tree(), as we do today? The cover letter says this is all so that we can run DT tests for the clk framework; why can't that just depend on the system being booted with DT rather than ACPI? We have other tests which are architecture and/or configuration dependent... Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel