On Wed, Dec 8, 2021 at 5:04 PM Kirill A. Shutemov
[off-list ref] wrote:

On Wed, Dec 08, 2021 at 04:10:52PM +0100, Rafael J. Wysocki wrote:

quoted

On Mon, Dec 6, 2021 at 1:30 PM Kirill A. Shutemov
[off-list ref] wrote:

quoted

According to the ACPI spec v6.4, section 16.2 the cache flushing
required on entering to S1, S2, and S3.

No need to flush caches on hibernation (S4).

Signed-off-by: Kirill A. Shutemov <redacted>
---
 drivers/acpi/sleep.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 14e8df0ac762..8166d863ed6b 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c

@@ -902,8 +902,6 @@ static int acpi_hibernation_enter(void)
 {
        acpi_status status = AE_OK;

-       ACPI_FLUSH_CPU_CACHE();
-
        /* This shouldn't return.  If it returns, we have a problem */
        status = acpi_enter_sleep_state(ACPI_STATE_S4);
        /* Reprogram control registers */
--

Applied (with some edits in the subject and changelog) as 5.17 material, thanks!

Is it for the series or only 4/4?

Just for the [4/4].

Do I need to do something for 2/4 and 3/4?

For [2/4] you do as per the comment and let me reply to the [3/4].