[PATCH 3/4] ACPI: processor idle: Only flush cache on entering C3

Kirill A. Shutemov
2021-12-06T12:30:10Z

According to the ACPI spec v6.4, section 8.2, cache flushing required
on entering C3 power state.

Avoid flushing cache on entering other power states.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
drivers/acpi/processor_idle.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 76ef1bcc8848..01495aca850e 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -567,7 +567,8 @@ 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) {

--
2.32.0