From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754233AbbCFRrb (ORCPT ); Fri, 6 Mar 2015 12:47:31 -0500 Received: from foss.arm.com ([217.140.101.70]:60662 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751328AbbCFRr0 (ORCPT ); Fri, 6 Mar 2015 12:47:26 -0500 Date: Fri, 6 Mar 2015 17:47:15 +0000 From: Lorenzo Pieralisi To: Hanjun Guo Cc: Catalin Marinas , "Rafael J. Wysocki" , Will Deacon , Olof Johansson , "grant.likely@linaro.org" , Arnd Bergmann , Mark Rutland , "graeme.gregory@linaro.org" , Sudeep Holla , "jcm@redhat.com" , 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" , Al Stone Subject: Re: [PATCH v9 18/21] ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 Message-ID: <20150306174715.GA26888@e102568-lin.cambridge.arm.com> References: <1424853601-6675-1-git-send-email-hanjun.guo@linaro.org> <1424853601-6675-19-git-send-email-hanjun.guo@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1424853601-6675-19-git-send-email-hanjun.guo@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 25, 2015 at 08:39:58AM +0000, Hanjun Guo wrote: > From: Al Stone > > ACPI reduced hardware mode is disabled by default, but ARM64 > can only run properly in ACPI hardware reduced mode, so select > ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64. Agreed. This will remove unneeded acpica code. I think though, you should also check the FADT flag HW_REDUCED_ACPI at boot to make sure that the tables are HW reduced compliant. I am flagging this up because I noticed code in core code (not guarded by ifdef) that checks: acpi_gbl_reduced_hardware and if it is not set it goes on instantiating fixed HW devices. drivers/acpi/scan.c:2567 It is just a heads up, I think it is harmless, but one thing is removing acpica code on ACPI HW reduced only, the other is to make sure the kernel does not try to use ACPI HW features that acpica can't support. Lorenzo > CC: Catalin Marinas > CC: Will Deacon > Reviewed-by: Grant Likely > Tested-by: Suravee Suthikulpanit > Tested-by: Yijing Wang > Tested-by: Mark Langsdorf > Tested-by: Jon Masters > Tested-by: Timur Tabi > Tested-by: Robert Richter > Acked-by: Robert Richter > Signed-off-by: Al Stone > Signed-off-by: Hanjun Guo > --- > arch/arm64/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 1b8e973..d00ab9a 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1,5 +1,6 @@ > config ARM64 > def_bool y > + select ACPI_REDUCED_HARDWARE_ONLY if ACPI > select ARCH_BINFMT_ELF_RANDOMIZE_PIE > select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE > select ARCH_HAS_GCOV_PROFILE_ALL > -- > 1.9.1 > >