1 files changed, 37 insertions, 1 deletions

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 7b8787b490f6..0b2707ee094b 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -95,6 +95,7 @@ enum {
          * due to bad math.
          */
         ACPI_BATTERY_QUIRK_SIGNED16_CURRENT,
+        ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY,
 };
 
 struct acpi_battery {
@@ -405,6 +406,8 @@ static int acpi_battery_get_info(struct acpi_battery *battery)
                 result = extract_package(battery, buffer.pointer,
                                 info_offsets, ARRAY_SIZE(info_offsets));
         kfree(buffer.pointer);
+        if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
+                battery->full_charge_capacity = battery->design_capacity;
         return result;
 }
 
@@ -441,6 +444,10 @@ static int acpi_battery_get_state(struct acpi_battery *battery)
             battery->rate_now != -1)
                 battery->rate_now = abs((s16)battery->rate_now);
 
+        if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags)
+            && battery->capacity_now >= 0 && battery->capacity_now <= 100)
+                battery->capacity_now = (battery->capacity_now *
+                                battery->full_charge_capacity) / 100;
         return result;
 }
 
@@ -552,6 +559,33 @@ static void acpi_battery_quirks(struct acpi_battery *battery)
         }
 }
 
+/*
+ * According to the ACPI spec, some kinds of primary batteries can
+ * report percentage battery remaining capacity directly to OS.
+ * In this case, it reports the Last Full Charged Capacity == 100
+ * and BatteryPresentRate == 0xFFFFFFFF.
+ *
+ * Now we found some battery reports percentage remaining capacity
+ * even if it's rechargeable.
+ * https://bugzilla.kernel.org/show_bug.cgi?id=15979
+ *
+ * Handle this correctly so that they won't break userspace.
+ */
+static void acpi_battery_quirks2(struct acpi_battery *battery)
+{
+        if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
+                return ;
+
+        if (battery->full_charge_capacity == 100 &&
+            battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN &&
+            battery->capacity_now >=0 && battery->capacity_now <= 100) {
+                set_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags);
+                battery->full_charge_capacity = battery->design_capacity;
+                battery->capacity_now = (battery->capacity_now *
+                                battery->full_charge_capacity) / 100;
+        }
+}
+
 static int acpi_battery_update(struct acpi_battery *battery)
 {
         int result, old_present = acpi_battery_present(battery);
@@ -573,7 +607,9 @@ static int acpi_battery_update(struct acpi_battery *battery)
         }
         if (!battery->bat.dev)
                 sysfs_add_battery(battery);
-        return acpi_battery_get_state(battery);
+        result = acpi_battery_get_state(battery);
+        acpi_battery_quirks2(battery);
+        return result;
 }
 
 /* --------------------------------------------------------------------------