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

PATCH RESEND Applied Rafael J. Wysocki 2 participants 2 messages Oct 23, 2010 ACPI

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Rafael J. Wysocki

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PATCH RESEND 1/1 ACPI / Battery: Return -ENODEV for unknown values in get_property()

From: Rafael J. Wysocki <[email protected]>

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 <[email protected]>
Signed-off-by Rafael J. Wysocki <[email protected]>
---
 drivers/acpi/battery.c |   35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)
drivers/acpi/battery.c +27 -8
Index: linux-2.6/drivers/acpi/battery.c
===================================================================
@@ -186,6 +186,7 @@ static int acpi_battery_get_property(str
 				     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(str
 		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(str
 		val->strval = battery->serial_number;
 		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
 	}
-	return 0;
+	return ret;
 }
 
 static enum power_supply_property charge_battery_props[] = {
reviewer Applied
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applied

thanks,
Len Brown, Intel Open Source Technology Center