[PATCH 2/2] ACPI / AC: recheck adapter status upon battery notifications

[Alexander Mezin <mezin.alexander@gmail.com>]

On HP Pavilion dv6-6179er there are no notifications when AC adapter
is plugged/unplugged.
However, when AC status is read (acpi_ac_get_state), and if AC status
has changed, AML code triggers the notification.

This patch solves the problem by re-reading AC adapter status upon
battery notifications.

Signed-off-by: Alexander Mezin <mezin.alexander@gmail.com>
---
 drivers/acpi/ac.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c
index 6f190bc..1d3903e 100644
--- a/drivers/acpi/ac.c
+++ b/drivers/acpi/ac.c
@@ -44,6 +44,8 @@
 #define ACPI_AC_STATUS_ONLINE		0x01
 #define ACPI_AC_STATUS_UNKNOWN		0xFF
 
+#define ACPI_BATTERY_CLASS		"battery"
+
 #define _COMPONENT		ACPI_AC_COMPONENT
 ACPI_MODULE_NAME("ac");
 
@@ -57,6 +59,7 @@ struct acpi_ac {
 	struct power_supply charger;
 	struct platform_device *pdev;
 	unsigned long long state;
+	struct notifier_block battery_nb;
 };
 
 #define to_acpi_ac(x) container_of(x, struct acpi_ac, charger)
@@ -152,6 +155,18 @@ static void acpi_ac_notify_handler(acpi_handle handle, u32 event, void *data)
 	return;
 }
 
+static int acpi_ac_battery_notify(struct notifier_block *nb,
+				  unsigned long action, void *data)
+{
+	struct acpi_ac *ac = container_of(nb, struct acpi_ac, battery_nb);
+	struct acpi_bus_event *event = (struct acpi_bus_event *)data;
+
+	if (strcmp(event->device_class, ACPI_BATTERY_CLASS) == 0)
+		acpi_ac_get_state(ac);
+
+	return NOTIFY_OK;
+}
+
 static int thinkpad_e530_quirk(const struct dmi_system_id *d)
 {
 	ac_sleep_before_get_state_ms = 1000;
@@ -215,6 +230,8 @@ static int acpi_ac_probe(struct platform_device *pdev)
 	       acpi_device_name(adev), acpi_device_bid(adev),
 	       ac->state ? "on-line" : "off-line");
 
+	ac->battery_nb.notifier_call = acpi_ac_battery_notify;
+	register_acpi_notifier(&ac->battery_nb);
 end:
 	if (result)
 		kfree(ac);
@@ -261,6 +278,7 @@ static int acpi_ac_remove(struct platform_device *pdev)
 	ac = platform_get_drvdata(pdev);
 	if (ac->charger.dev)
 		power_supply_unregister(&ac->charger);
+	unregister_acpi_notifier(&ac->battery_nb);
 
 	kfree(ac);
 
-- 
1.9.0