ACPI: Disable ARB_DISABLE on platforms where it is not needed

ARB_DISABLE is a NOP on all of the recent Intel platforms.

For such platforms, reduce contention on c3_lock
by skipping the fake ARB_DISABLE.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 72069ba5f1ed..4840c79fd8e0 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -512,7 +512,8 @@ static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
                                            struct acpi_processor_cx *cx)
 {
-        static int bm_check_flag;
+        static int bm_check_flag = -1;
+        static int bm_control_flag = -1;
 
 
         if (!cx->address)
@@ -542,12 +543,14 @@ static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
         }
 
         /* All the logic here assumes flags.bm_check is same across all CPUs */
-        if (!bm_check_flag) {
+        if (bm_check_flag == -1) {
                 /* Determine whether bm_check is needed based on CPU  */
                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
                 bm_check_flag = pr->flags.bm_check;
+                bm_control_flag = pr->flags.bm_control;
         } else {
                 pr->flags.bm_check = bm_check_flag;
+                pr->flags.bm_control = bm_control_flag;
         }
 
         if (pr->flags.bm_check) {