From kyle@infradead.org Wed Sep 22 18:35:38 2010
From: Matthew Garrett <mjg@redhat.com>
To: linux-acpi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Matthew Garrett <mjg@redhat.com>
Subject: [PATCH] acpi: Update battery information on notification 0x81
Date: 	Mon, 16 Aug 2010 16:32:19 -0400

A notification event 0x81 from an ACPI battery device requires us to
re-read the battery information structure. Do so, and if the battery's
reporting units have changed (as is the case on some Thinkpads) destroy
and recreate the battery in order to populate the fields correctly.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---

 drivers/acpi/battery.c |   21 ++++++++++++++++-----
 1 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 95649d3..161e43a 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -152,6 +152,7 @@ static int acpi_battery_technology(struct acpi_battery *battery)
 	return POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
 }
 
+static int acpi_battery_update(struct acpi_battery *battery, bool get_info);
 static int acpi_battery_get_state(struct acpi_battery *battery);
 
 static int acpi_battery_is_charged(struct acpi_battery *battery)
@@ -605,9 +606,11 @@ static void acpi_battery_quirks2(struct acpi_battery *battery)
 	}
 }
 
-static int acpi_battery_update(struct acpi_battery *battery)
+static int acpi_battery_update(struct acpi_battery *battery, bool get_info)
 {
 	int result, old_present = acpi_battery_present(battery);
+	int old_power_unit = battery->power_unit;
+
 	result = acpi_battery_get_status(battery);
 	if (result)
 		return result;
@@ -626,6 +629,14 @@ static int acpi_battery_update(struct acpi_battery *battery)
 	}
 	if (!battery->bat.dev)
 		sysfs_add_battery(battery);
+	if (get_info) {
+		acpi_battery_get_info(battery);
+		if (old_power_unit != battery->power_unit) {
+			/* The battery has changed its reporting units */
+			sysfs_remove_battery(battery);
+			sysfs_add_battery(battery);
+		}
+	}
 	result = acpi_battery_get_state(battery);
 	acpi_battery_quirks2(battery);
 	return result;
@@ -803,7 +814,7 @@ static print_func acpi_print_funcs[ACPI_BATTERY_NUMFILES] = {
 static int acpi_battery_read(int fid, struct seq_file *seq)
 {
 	struct acpi_battery *battery = seq->private;
-	int result = acpi_battery_update(battery);
+	int result = acpi_battery_update(battery, false);
 	return acpi_print_funcs[fid](seq, result);
 }
 
@@ -914,7 +925,7 @@ static void acpi_battery_notify(struct acpi_device *device, u32 event)
 	if (!battery)
 		return;
 	old = battery->bat.dev;
-	acpi_battery_update(battery);
+	acpi_battery_update(battery, (event == ACPI_BATTERY_NOTIFY_INFO));
 	acpi_bus_generate_proc_event(device, event,
 				     acpi_battery_present(battery));
 	acpi_bus_generate_netlink_event(device->pnp.device_class,
@@ -943,7 +954,7 @@ static int acpi_battery_add(struct acpi_device *device)
 	if (ACPI_SUCCESS(acpi_get_handle(battery->device->handle,
 			"_BIX", &handle)))
 		set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);
-	acpi_battery_update(battery);
+	acpi_battery_update(battery, false);
 #ifdef CONFIG_ACPI_PROCFS_POWER
 	result = acpi_battery_add_fs(device);
 #endif
@@ -984,7 +995,7 @@ static int acpi_battery_resume(struct acpi_device *device)
 		return -EINVAL;
 	battery = acpi_driver_data(device);
 	battery->update_time = 0;
-	acpi_battery_update(battery);
+	acpi_battery_update(battery, true);
 	return 0;
 }