[PATCH 1/2] ACPI ac: update AC status first when querying from sysfs

[PATCH 1/2] ACPI ac: update AC status first when querying from sysfs

[Zhang Rui]

Sometimes the AC driver doesn't get notifications when it's
plugged/unplugged. And this results in the incorrect AC status
reported by the power supply sysfs I/F.
http://marc.info/?l=linux-acpi&m=128855015826728&w=2
https://bugzilla.kernel.org/show_bug.cgi?id=21722

Update the AC status first when querying from sysfs.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Seblu <seblu@seblu.net>
---
 drivers/acpi/ac.c |   45 ++++++++++++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 17 deletions(-)

Index: linux-2.6/drivers/acpi/ac.c
===================================================================
--- linux-2.6.orig/drivers/acpi/ac.c
+++ linux-2.6/drivers/acpi/ac.c
@@ -100,24 +100,7 @@ static const struct file_operations acpi
 	.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 +123,34 @@ static int acpi_ac_get_state(struct acpi
 	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)