Re: [PATCH v10 00/21] Introduce ACPI for ARM64 based on ACPI 5.1
From: Rafael J. Wysocki
Date: Sun Mar 22 2015 - 17:47:27 EST
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 <hanjun.guo@xxxxxxxxxx <mailto:hanjun.guo@xxxxxxxxxx>>
> >>> 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 <hanjun.guo@xxxxxxxxxx
> >>> <mailto:hanjun.guo@xxxxxxxxxx>>
> >>> ---
> >>> 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.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/