4.9-stable review patch. If anyone has any objections, please let me know.
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From: Martin Kelly martin@martingkelly.com
commit fe5192ac81ad0d4dfe1395d11f393f0513c15f7f upstream.
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@martingkelly.com Tested-by: Denis Ciocca denis.ciocca@st.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/iio/magnetometer/st_magn_buffer.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)
--- 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_tr 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(str 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(str 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 @@ st_magn_buffer_predisable_error: }
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, };