ACPI ac: update AC status upon sysfs query

http://marc.info/?l=linux-acpi&m=128855015826728&w=2
https://bugzilla.kernel.org/show_bug.cgi?id=21722

Tested_by: Seblu <seblu@seblu.net>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/ac.c

@@ -100,24 +100,7 @@ static const struct file_operations acpi_ac_fops = {
 	.release = single_release,
 };
 #endif
-static int get_ac_property(struct power_supply *psy,
-			   enum power_supply_property psp,
-			   union power_supply_propval *val)
-{
-	struct acpi_ac *ac = to_acpi_ac(psy);
-	switch (psp) {
-	case POWER_SUPPLY_PROP_ONLINE:
-		val->intval = ac->state;
-		break;
-	default:
-		return -EINVAL;
-	}
-	return 0;
-}
 
-static enum power_supply_property ac_props[] = {
-	POWER_SUPPLY_PROP_ONLINE,
-};
 /* --------------------------------------------------------------------------
                                AC Adapter Management
    -------------------------------------------------------------------------- */
@@ -140,6 +123,35 @@ static int acpi_ac_get_state(struct acpi_ac *ac)
 	return 0;
 }
 
+/* --------------------------------------------------------------------------
+                            sysfs I/F
+   -------------------------------------------------------------------------- */
+static int get_ac_property(struct power_supply *psy,
+			   enum power_supply_property psp,
+			   union power_supply_propval *val)
+{
+	struct acpi_ac *ac = to_acpi_ac(psy);
+
+	if (!ac)
+		return -ENODEV;
+
+	if (acpi_ac_get_state(ac))
+		return -ENODEV;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = ac->state;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static enum power_supply_property ac_props[] = {
+	POWER_SUPPLY_PROP_ONLINE,
+};
+
 #ifdef CONFIG_ACPI_PROCFS_POWER
 /* --------------------------------------------------------------------------
                               FS Interface (/proc)