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Subject[Resend][PATCH] ACPI / Battery: Return -ENODEV for unknown values in get_property()
Date
From: Rafael J. Wysocki <rjw@sisk.pl>

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>
---
drivers/acpi/battery.c | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)
Index: linux-2.6/drivers/acpi/battery.c
===================================================================
--- linux-2.6.orig/drivers/acpi/battery.c
+++ 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[] = {

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