This is a note to let you know that I've just added the patch titled
iio:st_magn: Fix enable device after trigger
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From fe5192ac81ad0d4dfe1395d11f393f0513c15f7f Mon Sep 17 00:00:00 2001
From: Martin Kelly <martin@xxxxxxxxxxxxxxxx>
Date: Sun, 28 Oct 2018 20:18:53 -0700
Subject: iio:st_magn: Fix enable device after trigger
Currently, we enable the device before we enable the device trigger. At
high frequencies, this can cause interrupts that don't yet have a poll
function associated with them and are thus treated as spurious. At high
frequencies with level interrupts, this can even cause an interrupt storm
of repeated spurious interrupts (~100,000 on my Beagleboard with the
LSM9DS1 magnetometer). If these repeat too much, the interrupt will get
disabled and the device will stop functioning.
To prevent these problems, enable the device prior to enabling the device
trigger, and disable the divec prior to disabling the trigger. This means
there's no window of time during which the device creates interrupts but we
have no trigger to answer them.
Fixes: 90efe055629 ("iio: st_sensors: harden interrupt handling")
Signed-off-by: Martin Kelly <martin@xxxxxxxxxxxxxxxx>
Tested-by: Denis Ciocca <denis.ciocca@xxxxxx>
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
drivers/iio/magnetometer/st_magn_buffer.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/iio/magnetometer/st_magn_buffer.c b/drivers/iio/magnetometer/st_magn_buffer.c
index 0a9e8fadfa9d..37ab30566464 100644
--- a/drivers/iio/magnetometer/st_magn_buffer.c
+++ b/drivers/iio/magnetometer/st_magn_buffer.c
@@ -30,11 +30,6 @@ int st_magn_trig_set_state(struct iio_trigger *trig, bool state)
return st_sensors_set_dataready_irq(indio_dev, state);
}
-static int st_magn_buffer_preenable(struct iio_dev *indio_dev)
-{
- return st_sensors_set_enable(indio_dev, true);
-}
-
static int st_magn_buffer_postenable(struct iio_dev *indio_dev)
{
int err;
@@ -50,7 +45,7 @@ static int st_magn_buffer_postenable(struct iio_dev *indio_dev)
if (err < 0)
goto st_magn_buffer_postenable_error;
- return err;
+ return st_sensors_set_enable(indio_dev, true);
st_magn_buffer_postenable_error:
kfree(mdata->buffer_data);
@@ -63,11 +58,11 @@ static int st_magn_buffer_predisable(struct iio_dev *indio_dev)
int err;
struct st_sensor_data *mdata = iio_priv(indio_dev);
- err = iio_triggered_buffer_predisable(indio_dev);
+ err = st_sensors_set_enable(indio_dev, false);
if (err < 0)
goto st_magn_buffer_predisable_error;
- err = st_sensors_set_enable(indio_dev, false);
+ err = iio_triggered_buffer_predisable(indio_dev);
st_magn_buffer_predisable_error:
kfree(mdata->buffer_data);
@@ -75,7 +70,6 @@ static int st_magn_buffer_predisable(struct iio_dev *indio_dev)
}
static const struct iio_buffer_setup_ops st_magn_buffer_setup_ops = {
- .preenable = &st_magn_buffer_preenable,
.postenable = &st_magn_buffer_postenable,
.predisable = &st_magn_buffer_predisable,
};
--
2.19.1
