| Message ID | 20231124182747.13956-1-W_Armin@gmx.de (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | hwmon: (acpi_power_meter) Fix 4.29 MW bug | expand |
On Fri, Nov 24, 2023 at 07:27:47PM +0100, Armin Wolf wrote: > The ACPI specification says: > > "If an error occurs while obtaining the meter reading or if the value > is not available then an Integer with all bits set is returned" > > Since the "integer" is 32 bits in case of the ACPI power meter, > userspace will get a power reading of 2^32 * 1000 miliwatts (~4.29 MW) > in case of such an error. This was discovered due to a lm_sensors > bugreport (https://github.com/lm-sensors/lm-sensors/issues/460). > Fix this by returning -ENODATA instead. > > Tested-by: <urbinek@gmail.com> > Fixes: de584afa5e18 ("hwmon driver for ACPI 4.0 power meters") > Signed-off-by: Armin Wolf <W_Armin@gmx.de> Applied. Thanks, Guenter > --- > drivers/hwmon/acpi_power_meter.c | 4 ++++ > 1 file changed, 4 insertions(+) > > -- > 2.39.2 > > diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c > index 8db740214ffd..703666b95bf4 100644 > --- a/drivers/hwmon/acpi_power_meter.c > +++ b/drivers/hwmon/acpi_power_meter.c > @@ -31,6 +31,7 @@ > #define POWER_METER_CAN_NOTIFY (1 << 3) > #define POWER_METER_IS_BATTERY (1 << 8) > #define UNKNOWN_HYSTERESIS 0xFFFFFFFF > +#define UNKNOWN_POWER 0xFFFFFFFF > > #define METER_NOTIFY_CONFIG 0x80 > #define METER_NOTIFY_TRIP 0x81 > @@ -348,6 +349,9 @@ static ssize_t show_power(struct device *dev, > update_meter(resource); > mutex_unlock(&resource->lock); > > + if (resource->power == UNKNOWN_POWER) > + return -ENODATA; > + > return sprintf(buf, "%llu\n", resource->power * 1000); > }
diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c index 8db740214ffd..703666b95bf4 100644 --- a/drivers/hwmon/acpi_power_meter.c +++ b/drivers/hwmon/acpi_power_meter.c @@ -31,6 +31,7 @@ #define POWER_METER_CAN_NOTIFY (1 << 3) #define POWER_METER_IS_BATTERY (1 << 8) #define UNKNOWN_HYSTERESIS 0xFFFFFFFF +#define UNKNOWN_POWER 0xFFFFFFFF #define METER_NOTIFY_CONFIG 0x80 #define METER_NOTIFY_TRIP 0x81 @@ -348,6 +349,9 @@ static ssize_t show_power(struct device *dev, update_meter(resource); mutex_unlock(&resource->lock); + if (resource->power == UNKNOWN_POWER) + return -ENODATA; + return sprintf(buf, "%llu\n", resource->power * 1000); }