Thread (29 messages) 29 messages, 7 authors, 2021-12-17

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

From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: 2021-12-08 15:11:06
Also in: lkml

On Mon, Dec 6, 2021 at 1:30 PM Kirill A. Shutemov
[off-list ref] wrote:
quoted hunk ↗ jump to hunk
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!
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