[PATCH] acpi: Update battery information on notification 0x81

[Matthew Garrett <mjg59@srcf.ucam.org>]

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>
---

Respun against Linus master

 drivers/acpi/battery.c |   24 +++++++++++++++++-------
 1 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 9fb9d5a..8da9c88 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -130,7 +130,7 @@ struct acpi_battery {
 	unsigned long flags;
 };
 
-static int acpi_battery_update(struct acpi_battery *battery);
+static int acpi_battery_update(struct acpi_battery *battery, bool get_info);
 
 #define to_acpi_battery(x) container_of(x, struct acpi_battery, bat);
 
@@ -186,7 +186,7 @@ static int acpi_battery_get_property(struct power_supply *psy,
 	int ret = 0;
 	struct acpi_battery *battery = to_acpi_battery(psy);
 
-	if (acpi_battery_update(battery))
+	if (acpi_battery_update(battery, false))
 		return -ENODEV;
 
 	if (acpi_battery_present(battery)) {
@@ -610,9 +610,11 @@ 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;
@@ -631,6 +633,14 @@ 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;
@@ -808,7 +818,7 @@ 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);
 }
 
@@ -919,7 +929,7 @@ 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,
@@ -948,7 +958,7 @@ 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
@@ -989,7 +999,7 @@ 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;
 }

-- 
Matthew Garrett | mjg59@srcf.ucam.org