ACPI hibernation: Call _PTS before suspending devices

The ACPI 1.0 specification wants us to put devices into low power
states after executing the _PTS global control method, while ACPI
2.0 and later want us to do that in the reverse order. The current
hibernation code follows ACPI 2.0 in that respect which may cause some
ACPI 1.0x systems to hang during hibernation (ref.
http://bugzilla.kernel.org/show_bug.cgi?id=9528).

Make the hibernation code execute _PTS before putting devices into
low power states (ie. in accordance with ACPI 1.0x) with the
possibility to override that using the 'acpi_new_pts_ordering' kernel
command line option.

Signed-off-by: Rafael J. Wysocki <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

drivers/acpi/sleep/main.c

···
 #ifdef CONFIG_HIBERNATION
 static int acpi_hibernation_begin(void)
 {
+	int error;
+
 	acpi_target_sleep_state = ACPI_STATE_S4;
-	return 0;
+	if (new_pts_ordering)
+		return 0;
+
+	error = acpi_sleep_prepare(ACPI_STATE_S4);
+	if (error)
+		acpi_target_sleep_state = ACPI_STATE_S0;
+	else
+		acpi_sleep_finish_wake_up = true;
+
+	return error;
 }
 
 static int acpi_hibernation_prepare(void)
 {
-	int error;
+	if (new_pts_ordering) {
+		int error = acpi_sleep_prepare(ACPI_STATE_S4);
 
-	error = acpi_sleep_prepare(ACPI_STATE_S4);
-	if (error)
-		return error;
+		if (error) {
+			acpi_target_sleep_state = ACPI_STATE_S0;
+			return error;
+		}
+		acpi_sleep_finish_wake_up = true;
+	}
 
-	if (!ACPI_SUCCESS(acpi_hw_disable_all_gpes()))
-		error = -EFAULT;
-
-	return error;
+	return ACPI_SUCCESS(acpi_hw_disable_all_gpes()) ? 0 : -EFAULT;
 }
 
 static int acpi_hibernation_enter(void)
···
 	acpi_set_firmware_waking_vector((acpi_physical_address) 0);
 
 	acpi_target_sleep_state = ACPI_STATE_S0;
+	acpi_sleep_finish_wake_up = false;
 }
 
 static void acpi_hibernation_end(void)
 {
 	/*
 	 * This is necessary in case acpi_hibernation_finish() is not called
-	 * during a failing transition to the sleep state.
+	 * directly during a failing transition to the sleep state.
 	 */
-	acpi_target_sleep_state = ACPI_STATE_S0;
+	if (acpi_sleep_finish_wake_up)
+		acpi_hibernation_finish();
 }
 
 static int acpi_hibernation_pre_restore(void)