From: Lars-Peter Clausen lars@metafoo.de
[ Upstream commit 0178297c1e6898e2197fe169ef3be723e019b971 ]
On PREEMPT_RT enabled kernels unmarked hrtimers are moved into soft interrupt expiry mode by default.
The IIO hrtimer-trigger needs to run in hard interrupt context since it will end up calling generic_handle_irq() which has the requirement to run in hard interrupt context.
Explicitly specify that the timer needs to run in hard interrupt context by using the HRTIMER_MODE_REL_HARD flag.
Fixes: f5c2f0215e36 ("hrtimer: Move unmarked hrtimers to soft interrupt expiry on RT") Reported-by: Christian Eggers ceggers@arri.de Signed-off-by: Lars-Peter Clausen lars@metafoo.de Acked-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Link: https://lore.kernel.org/r/20201117103751.16131-1-lars@metafoo.de Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iio/trigger/iio-trig-hrtimer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/trigger/iio-trig-hrtimer.c b/drivers/iio/trigger/iio-trig-hrtimer.c index f59bf8d585866..410de837d0417 100644 --- a/drivers/iio/trigger/iio-trig-hrtimer.c +++ b/drivers/iio/trigger/iio-trig-hrtimer.c @@ -102,7 +102,7 @@ static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
if (state) hrtimer_start(&trig_info->timer, trig_info->period, - HRTIMER_MODE_REL); + HRTIMER_MODE_REL_HARD); else hrtimer_cancel(&trig_info->timer);
@@ -132,7 +132,7 @@ static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name) trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops; trig_info->swt.trigger->dev.groups = iio_hrtimer_attr_groups;
- hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); trig_info->timer.function = iio_hrtimer_trig_handler;
trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY;