1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 65132f920459..69cbc57c2d1c 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -138,6 +138,29 @@ static int acpi_battery_technology(struct acpi_battery *battery)
 
 static int acpi_battery_get_state(struct acpi_battery *battery);
 
+static int acpi_battery_is_charged(struct acpi_battery *battery)
+{
+        /* either charging or discharging */
+        if (battery->state != 0)
+                return 0;
+
+        /* battery not reporting charge */
+        if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN ||
+            battery->capacity_now == 0)
+                return 0;
+
+        /* good batteries update full_charge as the batteries degrade */
+        if (battery->full_charge_capacity == battery->capacity_now)
+                return 1;
+
+        /* fallback to using design values for broken batteries */
+        if (battery->design_capacity == battery->capacity_now)
+                return 1;
+
+        /* we don't do any sort of metric based on percentages */
+        return 0;
+}
+
 static int acpi_battery_get_property(struct power_supply *psy,
                                      enum power_supply_property psp,
                                      union power_supply_propval *val)
@@ -155,7 +178,7 @@ static int acpi_battery_get_property(struct power_supply *psy,
                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
                 else if (battery->state & 0x02)
                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
-                else if (battery->state == 0)
+                else if (acpi_battery_is_charged(battery))
                         val->intval = POWER_SUPPLY_STATUS_FULL;
                 else
                         val->intval = POWER_SUPPLY_STATUS_UNKNOWN;