Re: [PATCH 4/4] ACPI: PM: Avoid cache flush on entering S4

[Rafael J. Wysocki]

On Mon, Dec 6, 2021 at 1:30 PM Kirill A. Shutemov
<kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
>
> 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 <kirill.shutemov@xxxxxxxxxxxxxxx>
> ---
>  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!