ACPI: PM: Avoid CPU cache flush when entering S4

kiryl · rafaeljw · commit 53d01e2016d7 · 2021-12-08T16:09:25.000+01:00
According to ACPI 6.4, Section 16.2, the CPU cache flushing is
required on entering to S1, S2, and S3.

No need to flush the caches during hibernation (S4).

Signed-off-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
@@ -903,8 +903,6 @@ 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 */

Original file line number	Diff line number	Diff line change
`@@ -903,8 +903,6 @@ static int acpi_hibernation_enter(void)`
`903`	`903`	`{`
`904`	`904`	`acpi_status status = AE_OK;`
`905`	`905`
`906`		`- ACPI_FLUSH_CPU_CACHE();`
`907`		`-`
`908`	`906`	`/* This shouldn't return. If it returns, we have a problem */`
`909`	`907`	`status = acpi_enter_sleep_state(ACPI_STATE_S4);`
`910`	`908`	`/* Reprogram control registers */`