From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752101AbbABQr5 (ORCPT ); Fri, 2 Jan 2015 11:47:57 -0500 Received: from service87.mimecast.com ([91.220.42.44]:36500 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750717AbbABQrz convert rfc822-to-8bit (ORCPT ); Fri, 2 Jan 2015 11:47:55 -0500 Mime-Version: 1.0 (1.0) Subject: Re: [PATCH v5 18/18] Documentation: ACPI for ARM64 From: Catalin Marinas X-Mailer: iPhone Mail (12B440) In-Reply-To: <54A664AB.3030101@linaro.org> Date: Fri, 2 Jan 2015 16:47:51 +0000 Cc: Graeme Gregory , "ashwinc@codeaurora.org" , "rjw@rjwysocki.net" , Mark Rutland , "olof@lixom.net" , "grant.likely@linaro.org" , Will Deacon , "linaro-acpi@lists.linaro.org" , Liviu Dudau , "lv.zheng@intel.com" , "robh@kernel.org" , Lorenzo Pieralisi , "al.stone@linaro.org" , "daniel.lezcano@linaro.org" , "robert.moore@intel.com" , "linux-acpi@vger.kernel.org" , Charles Garcia-Tobin , "rric@kernel.org" , "jason@lakedaemon.net" , "arnd@arndb.de" , Marc Zyngier , "jcm@redhat.com" , "broonie@kernel.org" , "bhelgaas@google.com." , "graeme.gregory@linaro.org" , "Kangkang.Shen@huawei.com" , "rdunlap@infradead.org" , "linux-kernel@vger.kernel.org" , Sudeep Holla Message-Id: References: <1413553034-20956-1-git-send-email-hanjun.guo@linaro.org> <1413553034-20956-19-git-send-email-hanjun.guo@linaro.org> <8fc9550c96a468b3e50d51a37db68a33.squirrel@www.codeaurora.org> <54A3B526.9040903@linaro.org> <20150101200424.GB12770@xora-haswell.xora.org.uk> <54A664AB.3030101@linaro.org> To: Hanjun Guo X-OriginalArrivalTime: 02 Jan 2015 16:47:50.0162 (UTC) FILETIME=[D829B720:01D026AB] X-MC-Unique: 115010216475200601 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2 Jan 2015, at 09:28, Hanjun Guo wrote: >>> On 2015年01月02日 04:04, Graeme Gregory wrote: >>>> On Wed, Dec 31, 2014 at 04:34:46PM +0800, Hanjun Guo wrote: >>>> On 2014年12月31日 04:13, ashwinc@codeaurora.org wrote: >>>> Hi Hanjun, >>>> >>>> Overall the document looks good to us. Some minor clarifications below. >>>> >>>>> ---------- Forwarded message ---------- >>>>> From: Graeme Gregory >>>>> >>>>> Add documentation for the guidelines of how to use ACPI >>>>> on ARM64. >>>>> >>>>> Signed-off-by: Graeme Gregory >>>>> Signed-off-by: Al Stone >>>>> Signed-off-by: Hanjun Guo >>>>> --- >>>>> Documentation/arm64/arm-acpi.txt | 323 >>>>> ++++++++++++++++++++++++++++++++++++++ >>>>> 1 file changed, 323 insertions(+) >>>>> create mode 100644 Documentation/arm64/arm-acpi.txt >>>> >>>> [..] >>>> >>>>> +Relationship with Device Tree >>>>> +----------------------------- >>>> >>>> [..] >>>> >>>>> +When booting using ACPI tables, the /chosen node in DT will still be >>>>> parsed >>>>> +to extract the kernel command line and initrd path. No other section of >>>>> the >>>>> +DT will be used. >>>> >>>> Is this still true? >>> >>> No, we can booting the ACPI system in EFI stub without dtb. Catalin >>> also pointed out this issue, I will remove this paragraph. >> >> The paragraph is still correct, the /chosen node is always present even >> if nothing else is. > > Sorry for the confusing, I mean no dtb needed for the command line if > ACPI tables are available. > > efi will create a empty dtb if no dtb found, and add the cmd line into > the new created dtb, I'm just wondering, can we remove the limitation > for passing the cmd line in /chosen node in the future? My point is that on an ACPI based system, we don't really care how EFI_STUB passes the command line to the rest of the kernel. Since UEFI doesn't need to know about such detail and since ACPI is only supported with EFI_STUB, we don't need to mention the chosen node in this document. At some point we may even change the way EFI_STUB passes the command line to the kernel but this is still irrelevant to ACPI. Catalin