After enabling/disabling interrupts on the vcnl4040 chip the als and/or
ps sensor is powered on or off depending on the interrupt enable bits.
This is made as a last step in write_event_config.
But there is no reason to do this as the runtime PM handles the power
state of the sensors. Interfering with this may impact sensor readings.
Consider the following:
1. Userspace makes sensor data reading which triggers 2000ms RPM resume
(sensor powered on) timeout
2. Userspace disables interrupts => powers sensor off
3. Userspace reads sensor data = 0 because sensor is off and RPM didn't
power on the sensor as resume timeout is still active
4. RPM resume timeout passed
Powering sensor off in (2) risks a time window of close to 2000ms where
sensor data readings are disabled as in (3).
Skip setting power state when writing new event config.
Signed-off-by: Mårten Lindahl <marten.lindahl@xxxxxxxx>
---
drivers/iio/light/vcnl4000.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
index 3a52b09c2823..fdf763a04b0b 100644
--- a/drivers/iio/light/vcnl4000.c
+++ b/drivers/iio/light/vcnl4000.c
@@ -1513,7 +1513,6 @@ static int vcnl4040_write_event_config(struct iio_dev *indio_dev,
out:
mutex_unlock(&data->vcnl4000_lock);
- data->chip_spec->set_power_state(data, data->ps_int || data->als_int);
return ret;
}
---
base-commit: 7ba2090ca64ea1aa435744884124387db1fac70f
change-id: 20230907-vcnl4000-pm-fix-b58dc0dffb5c
Best regards,
--
Mårten Lindahl <marten.lindahl@xxxxxxxx>
