ACPI: PM: Call pm_set_suspend_via_firmware() during hibernation

On systems with ACPI platform firmware the last stage of hibernation
is analogous to system suspend to S3 (suspend-to-RAM), so it should
be handled analogously.  In particular, pm_suspend_via_firmware()
should return 'true' in that stage to let the callers of it know that
control will be passed to the platform firmware going forward, so
pm_set_suspend_via_firmware() needs to be called then in analogy with
acpi_suspend_begin().

However, the platform hibernation ->begin() callback is invoked
during the "freeze" transition (before creating a snapshot image of
system memory) as well as during the "hibernate" transition which is
the last stage of it and pm_set_suspend_via_firmware() should be
invoked by that callback in the latter stage only.

In order to implement that redefine the hibernation ->begin()
callback to take a pm_message_t argument to indicate which stage
of hibernation is taking place and rework acpi_hibernation_begin()
and acpi_hibernation_begin_old() to take it into account as needed.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 24 insertions, 15 deletions

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index e52f1238d2d6..a34deccd7317 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -1132,15 +1132,19 @@ void __init acpi_no_s4_hw_signature(void)
 	nosigcheck = true;
 }
 
-static int acpi_hibernation_begin(void)
+static int acpi_hibernation_begin(pm_message_t stage)
 {
-	int error;
+	if (!nvs_nosave) {
+		int error = suspend_nvs_alloc();
+		if (error)
+			return error;
+	}
 
-	error = nvs_nosave ? 0 : suspend_nvs_alloc();
-	if (!error)
-		acpi_pm_start(ACPI_STATE_S4);
+	if (stage.event == PM_EVENT_HIBERNATE)
+		pm_set_suspend_via_firmware();
 
-	return error;
+	acpi_pm_start(ACPI_STATE_S4);
+	return 0;
 }
 
 static int acpi_hibernation_enter(void)
@@ -1200,7 +1204,7 @@ static const struct platform_hibernation_ops acpi_hibernation_ops = {
  *		function is used if the pre-ACPI 2.0 suspend ordering has been
  *		requested.
  */
-static int acpi_hibernation_begin_old(void)
+static int acpi_hibernation_begin_old(pm_message_t stage)
 {
 	int error;
 	/*
@@ -1211,16 +1215,21 @@ static int acpi_hibernation_begin_old(void)
 	acpi_sleep_tts_switch(ACPI_STATE_S4);
 
 	error = acpi_sleep_prepare(ACPI_STATE_S4);
+	if (error)
+		return error;
 
-	if (!error) {
-		if (!nvs_nosave)
-			error = suspend_nvs_alloc();
-		if (!error) {
-			acpi_target_sleep_state = ACPI_STATE_S4;
-			acpi_scan_lock_acquire();
-		}
+	if (!nvs_nosave) {
+		error = suspend_nvs_alloc();
+		if (error)
+			return error;
 	}
-	return error;
+
+	if (stage.event == PM_EVENT_HIBERNATE)
+		pm_set_suspend_via_firmware();
+
+	acpi_target_sleep_state = ACPI_STATE_S4;
+	acpi_scan_lock_acquire();
+	return 0;
 }
 
 /*