ACPI / Battery: Return -ENODEV for unknown values in get_property()

The function acpi_battery_get_property() is called by the
power supply framework's function power_supply_show_property()
implementing the sysfs interface for power supply devices as the
ACPI battery driver's ->get_property() callback.  Thus it is supposed
to return error code if the value of the given property is unknown.
Unfortunately, however, it returns 0 in those cases and puts a
wrong (negative) value into the intval field of the
union power_supply_propval object provided by
power_supply_show_property().  In consequence, wrong negative
values are read by user space from the battery's sysfs files.

Fix this by making acpi_battery_get_property() return -ENODEV
for properties with unknown values (-ENODEV is returned, because
power_supply_uevent() returns with error for any other error code
returned by power_supply_show_property()).

Reported-and-tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 27 insertions, 8 deletions

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 98417201e9ce..ac74a7ddaaa4 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -186,6 +186,7 @@ static int acpi_battery_get_property(struct power_supply *psy,
                                      enum power_supply_property psp,
                                      union power_supply_propval *val)
 {
+        int ret = 0;
         struct acpi_battery *battery = to_acpi_battery(psy);
 
         if (acpi_battery_present(battery)) {
@@ -214,26 +215,44 @@ static int acpi_battery_get_property(struct power_supply *psy,
                 val->intval = battery->cycle_count;
                 break;
         case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
-                val->intval = battery->design_voltage * 1000;
+                if (battery->design_voltage == ACPI_BATTERY_VALUE_UNKNOWN)
+                        ret = -ENODEV;
+                else
+                        val->intval = battery->design_voltage * 1000;
                 break;
         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
-                val->intval = battery->voltage_now * 1000;
+                if (battery->voltage_now == ACPI_BATTERY_VALUE_UNKNOWN)
+                        ret = -ENODEV;
+                else
+                        val->intval = battery->voltage_now * 1000;
                 break;
         case POWER_SUPPLY_PROP_CURRENT_NOW:
         case POWER_SUPPLY_PROP_POWER_NOW:
-                val->intval = battery->rate_now * 1000;
+                if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN)
+                        ret = -ENODEV;
+                else
+                        val->intval = battery->rate_now * 1000;
                 break;
         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
         case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
-                val->intval = battery->design_capacity * 1000;
+                if (battery->design_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
+                        ret = -ENODEV;
+                else
+                        val->intval = battery->design_capacity * 1000;
                 break;
         case POWER_SUPPLY_PROP_CHARGE_FULL:
         case POWER_SUPPLY_PROP_ENERGY_FULL:
-                val->intval = battery->full_charge_capacity * 1000;
+                if (battery->full_charge_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
+                        ret = -ENODEV;
+                else
+                        val->intval = battery->full_charge_capacity * 1000;
                 break;
         case POWER_SUPPLY_PROP_CHARGE_NOW:
         case POWER_SUPPLY_PROP_ENERGY_NOW:
-                val->intval = battery->capacity_now * 1000;
+                if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN)
+                        ret = -ENODEV;
+                else
+                        val->intval = battery->capacity_now * 1000;
                 break;
         case POWER_SUPPLY_PROP_MODEL_NAME:
                 val->strval = battery->model_number;
@@ -245,9 +264,9 @@ static int acpi_battery_get_property(struct power_supply *psy,
                 val->strval = battery->serial_number;
                 break;
         default:
-                return -EINVAL;
+                ret = -EINVAL;
         }
-        return 0;
+        return ret;
 }
 
 static enum power_supply_property charge_battery_props[] = {