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authorAl Stone <al.stone@linaro.org>2014-01-17 11:51:30 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-02-05 12:28:07 +0100
commitaf1ae78abb324def77ba0c6c3a7c7678fb5cebbe (patch)
tree93f3d9190d1c93f01e848b99b256f7a77f903e87 /include/acpi
parent38dbfb59d1175ef458d006556061adeaa8751b72 (diff)
downloadop-kernel-dev-af1ae78abb324def77ba0c6c3a7c7678fb5cebbe.zip
op-kernel-dev-af1ae78abb324def77ba0c6c3a7c7678fb5cebbe.tar.gz
ACPI: introduce CONFIG_ACPI_REDUCED_HARDWARE_ONLY
ACPI hardware reduced mode exists to allow newer platforms to use a simpler form of ACPI that does not require supporting legacy versions of the specification and their associated hardware. This mode was introduced in the ACPI 5.0 specification. The ACPI hardware reduced mode is supposed to be used on systems having the HW_REDUCED_ACPI flag set in the FADT. ACPICA checks that flag to determine whether or not it should work in the HW reduced mode and there are pieces of code in it that will never be used in that case. Since some architecutres will always use the ACPI HW reduced mode, it doesn't make sense for them to ever compile support for anything else. Thus, they should set the flag ACPI_REDUCED_HARDWARE to TRUE in the ACPICA source. To enable them to do that, introduce a new kernel configuration option, CONFIG_ACPI_REDUCED_HARDWARE_ONLY, that will cause the ACPICA's ACPI_REDUCED_HARDWARE flag to be TRUE when set. Introducing this configuration item is based on suggestions from Lv Zheng saying that this does not belong in ACPICA, but rather to the Linux kernel itself. References: http://www.spinics.net/lists/linux-acpi/msg46369.html Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Al Stone <al.stone@linaro.org> [rjw: Subject and changelog] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/acpi')
-rw-r--r--include/acpi/platform/aclinux.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/acpi/platform/aclinux.h b/include/acpi/platform/aclinux.h
index 008aa28..30c9a7c 100644
--- a/include/acpi/platform/aclinux.h
+++ b/include/acpi/platform/aclinux.h
@@ -52,6 +52,12 @@
#ifdef __KERNEL__
+/* Compile for reduced hardware mode only with this kernel config */
+
+#ifdef CONFIG_ACPI_REDUCED_HARDWARE_ONLY
+#define ACPI_REDUCED_HARDWARE 1
+#endif
+
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
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