[PATCH] Revert "ACPI: processor: idle: Only flush cache on entering C3"

[Akihiko Odaki]

This reverts commit 87ebbb8c612b1214f227ebb8f25442c6d163e802.

ACPI processor power states can be transitioned in two distinct
situations: 1. when CPU goes idle and 2. before CPU goes offline
("playing dead") to suspend or hibernate. Case 1 is handled by
acpi_idle_enter or acpi_idle_enter_s2idle. Case 2 is handled by
acpi_idle_play_dead.

It is necessary to flush CPU caches in case 2 even if it is not
required to transit ACPI processor power states as CPU will go
offline soon. However, the reverted commit incorrectly removed CPU
cache flushing in such a condition. In fact, it made resuming from
suspend-to-RAM occasionally fail on Lenovo ThinkPad C13 Yoga.

Signed-off-by: Akihiko Odaki <akihiko.odaki@xxxxxxxxx>
---
 drivers/acpi/processor_idle.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index f8e9fa82cb9b..05b3985a1984 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -570,8 +570,7 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
 {
 	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
 
-	if (cx->type == ACPI_STATE_C3)
-		ACPI_FLUSH_CPU_CACHE();
+	ACPI_FLUSH_CPU_CACHE();
 
 	while (1) {
 
-- 
2.35.1