From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hanjun Guo Subject: Re: [PATCH v9 18/21] ARM64 / ACPI: Select ACPI_REDUCED_HARDWARE_ONLY if ACPI is enabled on ARM64 Date: Tue, 10 Mar 2015 20:23:03 +0800 Message-ID: <54FEE227.4000808@linaro.org> References: <1424853601-6675-1-git-send-email-hanjun.guo@linaro.org> <1424853601-6675-19-git-send-email-hanjun.guo@linaro.org> <20150306174715.GA26888@e102568-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-pd0-f176.google.com ([209.85.192.176]:37447 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752208AbbCJMXO (ORCPT ); Tue, 10 Mar 2015 08:23:14 -0400 Received: by pdbnh10 with SMTP id nh10so1382067pdb.4 for ; Tue, 10 Mar 2015 05:23:13 -0700 (PDT) In-Reply-To: <20150306174715.GA26888@e102568-lin.cambridge.arm.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lorenzo Pieralisi 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. On 2015=E5=B9=B403=E6=9C=8807=E6=97=A5 01:47, Lorenzo Pieralisi wrote: > 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 Agreed, I will add that check on top of this patch set. We explicitly stated that we are using hardware reduced mode on ARM64 in the doc, so,= =20 how about print some warning message and go on with the boot if we got the wrong flag HW_REDUCED_ACPI at boot? > 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. I agree, need some cleanups for the ACPICA code I think, and this was raised about 1 and half years ago and Intel folks need more consideration on that [1]. [1]: http://comments.gmane.org/gmane.linux.acpi.devel/63844 Thanks Hanjun -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html