Commit 0178297c authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

iio: hrtimer-trigger: Mark hrtimer to expire in hard interrupt context 



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: f5c2f021 ("hrtimer: Move unmarked hrtimers to soft interrupt expiry on RT")
Reported-by: default avatarChristian Eggers <ceggers@arri.de>
Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Acked-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20201117103751.16131-1-lars@metafoo.de


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 8a067200

drivers/iio/trigger/iio-trig-hrtimer.c

+2 −2
Original line number Diff line number Diff line
@@ -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;