ACPI: processor: idle: Only flush cache on entering C3

According to ACPI 6.4, Section 8.2, CPU cache flushing required on entering the C3 power state. Avoid flushing the cache on entering other C-states. Signed-off-by: Kirill A. Shutemov <[email protected]> [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki <[email protected]>
ashr · Dec 17, 2021 · 87ebbb8 · 87ebbb8
1 parent 0e6078c
commit 87ebbb8
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
@@ -565,7 +565,8 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 {
 	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 
-	ACPI_FLUSH_CPU_CACHE();
+	if (cx->type == ACPI_STATE_C3)
+		ACPI_FLUSH_CPU_CACHE();
 
 	while (1) {