From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Masters Subject: Re: [update][PATCH v10 06/21] ACPI / sleep: Introduce CONFIG_ACPI_GENERIC_SLEEP Date: Tue, 17 Mar 2015 01:59:30 -0400 Message-ID: <5507C2C2.1090509@redhat.com> References: <1426234469-6434-1-git-send-email-hanjun.guo@linaro.org> <3737028.Ib0fKlgSkd@vostro.rjw.lan> <5507933F.2020203@huawei.com> <10995588.scpoK3KRg2@vostro.rjw.lan> <5507A91A.1090206@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:36764 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751470AbbCQF7g (ORCPT ); Tue, 17 Mar 2015 01:59:36 -0400 In-Reply-To: <5507A91A.1090206@huawei.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Hanjun Guo , "Rafael J. Wysocki" Cc: Hanjun Guo , Catalin Marinas , Will Deacon , Olof Johansson , Grant Likely , Lorenzo Pieralisi , Arnd Bergmann , Mark Rutland , Graeme Gregory , Sudeep Holla , Marc Zyngier , Mark Brown , Robert Richter , Timur Tabi , Ashwin Chaugule , suravee.suthikulpanit@amd.com, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, Tomasz Nowicki , Zhangdianfang On 03/17/2015 12:10 AM, Hanjun Guo wrote: > On 2015/3/17 11:23, Rafael J. Wysocki wrote: >> On Tuesday, March 17, 2015 10:36:47 AM Hanjun Guo wrote: >> Well, almost. There is one problem with that, becuase sleep.c contains code >> outside of the ACPI_SLEEP-dependent blocks. That code is used for powering >> off ACPI platforms. >> >> I guess you don't want that code on ARM too, right? > > Yes, you are right. >> Perhaps we can use ACPI_REDUCED_HARDWARE_ONLY for that? ARM64 will be the > > Sorry, I can't fully understand your intention here, could you please > explain it more? > > Let me guess a little bit. Do you mean use ACPI_REDUCED_HARDWARE_ONLY for > powering off ACPI platforms? if so, I guess it's not a good idea, ACPI spec > only says that S4BIOS is not supported on HW-reduced ACPI platforms, S5 > has no such limitation, if I miss something here, please let me know. If helpful to the discussion, current SBBR (Server Base Boot Requirements[0]) design guidance is that for power off itself, we will prefer calling an EFI Runtime Service (that will preferentially call an PSCI - ARM Power State Coordination Interface - Secure Monitor Call (SMC - think SMI-like) internally to perform the shutdown/reboot) for the action of powering off or resetting 64-bit ARM SBBR platforms. Therefore if the alternative of an ACPI-based power off solution were not initially supported, I don't think it would have much practical impact, and it could be addressed after the initial support merged. That's just my $0.02. Jon. [0] The Server Base Boot Requirements are the platform specification we created for 64-bit ARM servers. They mandate the use of EFI and ACPI in compliant platforms: http://infocenter.arm.com/help/topic/com.arm.doc.den0044a/Server_Base_Boot_Requirements.pdf