On Wed, Feb 25, 2015 at 08:39:58AM +0000, Hanjun Guo wrote:
From: Al Stone al.stone@linaro.org
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 catalin.marinas@arm.com CC: Will Deacon will.deacon@arm.com Reviewed-by: Grant Likely grant.likely@linaro.org Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Yijing Wang wangyijing@huawei.com Tested-by: Mark Langsdorf mlangsdo@redhat.com Tested-by: Jon Masters jcm@redhat.com Tested-by: Timur Tabi timur@codeaurora.org Tested-by: Robert Richter rrichter@cavium.com Acked-by: Robert Richter rrichter@cavium.com Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org
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