[2.6.30-32.stable] ACPI: Be in TS_POLLING state during mwait based C-state entry

Commit Message

Len Brown Feb. 24, 2010, 3:35 a.m. UTC

None

Patch

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index e88e8ae..cc978a8 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -880,12 +880,14 @@  static int acpi_idle_enter_simple(struct cpuidle_device *dev,
 		return(acpi_idle_enter_c1(dev, state));
 
 	local_irq_disable();
-	current_thread_info()->status &= ~TS_POLLING;
-	/*
-	 * TS_POLLING-cleared state must be visible before we test
-	 * NEED_RESCHED:
-	 */
-	smp_mb();
+	if (cx->entry_method != ACPI_CSTATE_FFH) {
+		current_thread_info()->status &= ~TS_POLLING;
+		/*
+		 * TS_POLLING-cleared state must be visible before we test
+		 * NEED_RESCHED:
+		 */
+		smp_mb();
+	}
 
 	if (unlikely(need_resched())) {
 		current_thread_info()->status |= TS_POLLING;
@@ -965,12 +967,14 @@  static int acpi_idle_enter_bm(struct cpuidle_device *dev,
 	}
 
 	local_irq_disable();
-	current_thread_info()->status &= ~TS_POLLING;
-	/*
-	 * TS_POLLING-cleared state must be visible before we test
-	 * NEED_RESCHED:
-	 */
-	smp_mb();
+	if (cx->entry_method != ACPI_CSTATE_FFH) {
+		current_thread_info()->status &= ~TS_POLLING;
+		/*
+		 * TS_POLLING-cleared state must be visible before we test
+		 * NEED_RESCHED:
+		 */
+		smp_mb();
+	}
 
 	if (unlikely(need_resched())) {
 		current_thread_info()->status |= TS_POLLING;