ACPI: AC: Update AC state on resume

Check if AC state has changed across resume and notify userspace if so.

Fixes "[2.6.24-rc1 regression] AC adapter state does not change after resume"
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Tested-by: Andrey Borzenkov <arvidjaar@mail.ru>
Cc: Len Brown <lenb@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/acpi/ac.c

@@ -59,6 +59,7 @@ static int acpi_ac_open_fs(struct inode *inode, struct file *file);
 
 static int acpi_ac_add(struct acpi_device *device);
 static int acpi_ac_remove(struct acpi_device *device, int type);
+static int acpi_ac_resume(struct acpi_device *device);
 
 const static struct acpi_device_id ac_device_ids[] = {
 	{"ACPI0003", 0},
@@ -73,6 +74,7 @@ static struct acpi_driver acpi_ac_driver = {
 	.ops = {
 		.add = acpi_ac_add,
 		.remove = acpi_ac_remove,
+		.resume = acpi_ac_resume,
 		},
 };
 
@@ -307,6 +309,21 @@ static int acpi_ac_add(struct acpi_device *device)
 	return result;
 }
 
+static int acpi_ac_resume(struct acpi_device *device)
+{
+	struct acpi_ac *ac;
+	unsigned old_state;
+	if (!device || !acpi_driver_data(device))
+		return -EINVAL;
+	ac = acpi_driver_data(device);
+	old_state = ac->state;
+	if (acpi_ac_get_state(ac))
+		return 0;
+	if (old_state != ac->state)
+		kobject_uevent(&ac->charger.dev->kobj, KOBJ_CHANGE);
+	return 0;
+}
+
 static int acpi_ac_remove(struct acpi_device *device, int type)
 {
 	acpi_status status = AE_OK;