[PATCH] ACPI: PM: sleep: Do not set suspend_ops unnecessarily

["Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>]

From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

If none of the S1 - S3 sleep states is supported, it is not necessary
to register suspend_ops, so don't do that then.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
 drivers/acpi/sleep.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/acpi/sleep.c
===================================================================
--- linux-pm.orig/drivers/acpi/sleep.c
+++ linux-pm/drivers/acpi/sleep.c
@@ -815,14 +815,18 @@ void __weak acpi_s2idle_setup(void)
 
 static void acpi_sleep_suspend_setup(void)
 {
+	bool suspend_ops_needed = false;
 	int i;
 
 	for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++)
-		if (acpi_sleep_state_supported(i))
+		if (acpi_sleep_state_supported(i)) {
 			sleep_states[i] = 1;
+			suspend_ops_needed = true;
+		}
 
-	suspend_set_ops(old_suspend_ordering ?
-		&acpi_suspend_ops_old : &acpi_suspend_ops);
+	if (suspend_ops_needed)
+		suspend_set_ops(old_suspend_ordering ?
+				&acpi_suspend_ops_old : &acpi_suspend_ops);
 
 	acpi_s2idle_setup();
 }