From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751944AbbCVVrQ (ORCPT ); Sun, 22 Mar 2015 17:47:16 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:54320 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751854AbbCVVrO (ORCPT ); Sun, 22 Mar 2015 17:47:14 -0400 From: "Rafael J. Wysocki" To: Julien Grall Cc: Naresh Bhat , Hanjun Guo , Hanjun Guo , Jon Fraser , Parth Dixit , Stefano Stabellini , Catalin Marinas , Olof Johansson , "grant.likely@linaro.org" , Lorenzo Pieralisi , 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" , Ian Campbell Subject: Re: [PATCH v10 00/21] Introduce ACPI for ARM64 based on ACPI 5.1 Date: Sun, 22 Mar 2015 23:11:14 +0100 Message-ID: <5749112.zNnbMCHVxZ@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.19.0+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <550F3500.1040608@linaro.org> References: <1426077587-1561-1-git-send-email-hanjun.guo@linaro.org> <2189259.UNlTC1BNmt@vostro.rjw.lan> <550F3500.1040608@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sunday, March 22, 2015 09:32:48 PM Julien Grall wrote: > > On 22/03/2015 21:49, Rafael J. Wysocki wrote: > > On Sunday, March 22, 2015 09:05:21 PM Julien Grall wrote: > >> Hello, > >> > >> On 21/03/2015 12:09, Naresh Bhat wrote: > >>> From 268dcdafa34a690e2f99c0784ca33a6d2352ecf5 Mon Sep 17 00:00:00 2001 > >>> From: Hanjun Guo > > >>> Date: Sat, 21 Mar 2015 14:43:54 +0800 > >>> Subject: [PATCH] XEN / ACPI: Make XEN ACPI depend on X86 > >>> > >>> When ACPI is enabled on ARM64, XEN ACPI will also compiled > >>> into the kernel, but XEN ACPI is x86 dependent, so introduce > >>> CONFIG_XEN_ACPI to make it depend on x86 before XEN ACPI is > >>> functional on ARM64. > >>> > >>> Signed-off-by: Hanjun Guo >>> > > >>> --- > >>> drivers/xen/Kconfig | 4 ++++ > >>> drivers/xen/Makefile | 2 +- > >>> 2 files changed, 5 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > >>> index b812462..a31cd29 100644 > >>> --- a/drivers/xen/Kconfig > >>> +++ b/drivers/xen/Kconfig > >>> @@ -253,4 +253,8 @@ config XEN_EFI > >>> def_bool y > >>> depends on X86_64 && EFI > >>> > >>> +config XEN_ACPI > >>> + def_bool y > >>> + depends on X86 && ACPI > >>> + > >>> endmenu > >>> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile > >>> index 2ccd359..f4622ab 100644 > >>> --- a/drivers/xen/Makefile > >>> +++ b/drivers/xen/Makefile > >>> @@ -13,7 +13,7 @@ CFLAGS_efi.o += -fshort-wchar > >>> > >>> dom0-$(CONFIG_PCI) += pci.o > >>> dom0-$(CONFIG_USB_SUPPORT) += dbgp.o > >>> -dom0-$(CONFIG_ACPI) += acpi.o $(xen-pad-y) > >>> +dom0-$(CONFIG_XEN_ACPI) += acpi.o $(xen-pad-y) > >>> xen-pad-$(CONFIG_X86) += xen-acpi-pad.o > >>> dom0-$(CONFIG_X86) += pcpu.o > >>> obj-$(CONFIG_XEN_DOM0) += $(dom0-y) > >> > >> [..] > >> > >>> > >>> AFAIK, There is already a kernel patch exists to fix this issue. I > >>> think Julien or Parth is a right person to ask. Hence I am CCed Julien > >>> Grall too. > >> > >> The ACPI support for Xen is not ready. So I think avoiding to compile > >> drivers/xen/acpi.c on ARM64/ARM seems the better solution for now. > >> > >> Although, rather than introducing a new CONFIG option, I would use the > >> same trick we use within the Makefile to avoid hotplug.c on ARM/ARM64. > >> > >> ifeq ($(filter y, $(CONFIG_ARM) $(CONFIG_ARM64)), ) > >> dom0-$(CONFIG_ACPI) += acpi.o $(xen-pad-y) > >> endif > > > > Well, is avoiding an extra CONFIG_ option worth the ugliness of this? > > When the support of ACPI for Xen will come, the CONFIG_ option will be > an alias to CONFIG_XEN. > > In this case the CONFIG_ option won't bring much improvement to the code > and add an extra indirection. > > The "ugliness" option has, at least, the advantage to be tiny and > self-contained. Oh well, not really. You're moving a config-time check to compile time which means that it will be done every time this Makefile is executed and for all architectures that execute it. Not nice. Also I think that ia64 is missing from the list, but I may be wrong. Not to mention the fact that the dependency will be rather difficult to find for tools like xconfig ... -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.