From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Mon, 6 Dec 2021 15:29:51 +0300
Subject: ACPI: processor: idle: Only flush cache on entering C3
Patch-mainline: v5.17-rc1
Git-commit: 87ebbb8c612b1214f227ebb8f25442c6d163e802
References: jsc#PED-1408
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 <kirill.shutemov@linux.intel.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
drivers/acpi/processor_idle.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -565,7 +565,8 @@ static int acpi_idle_play_dead(struct cp
{
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) {