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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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