Merge commit 'v2.6.31-rc6' into core/rcu

Merge reason: the branch was on pre-rc1 .30, update to latest.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 13 insertions, 3 deletions

diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index bbbe4bb..8c44c23 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -34,12 +34,22 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
 		flags->bm_check = 1;
 	else if (c->x86_vendor == X86_VENDOR_INTEL) {
 		/*
-		 * Today all CPUs that support C3 share cache.
-		 * TBD: This needs to look at cache shared map, once
-		 * multi-core detection patch makes to the base.
+		 * Today all MP CPUs that support C3 share cache.
+		 * And caches should not be flushed by software while
+		 * entering C3 type state.
 		 */
 		flags->bm_check = 1;
 	}
+
+	/*
+	 * On all recent Intel platforms, ARB_DISABLE is a nop.
+	 * So, set bm_control to zero to indicate that ARB_DISABLE
+	 * is not required while entering C3 type state on
+	 * P4, Core and beyond CPUs
+	 */
+	if (c->x86_vendor == X86_VENDOR_INTEL &&
+	    (c->x86 > 0x6 || (c->x86 == 6 && c->x86_model >= 14)))
+			flags->bm_control = 0;
 }
 EXPORT_SYMBOL(acpi_processor_power_init_bm_check);