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Commit 330bdf62 authored by Ben Skeggs's avatar Ben Skeggs
Browse files

drm/nouveau/tmr: avoid processing completed alarms when adding a new one 



The idea here was to avoid having to "manually" program the HW if there's
a new earliest alarm.  This was lazy and bad, as it leads to loads of fun
races between inter-related callers (ie. therm).

Turns out, it's not so difficult after all.  Go figure ;)

Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org
parent 9fc64667

drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c

+13 −3
Original line number Diff line number Diff line
@@ -86,12 +86,22 @@ nvkm_timer_alarm(struct nvkm_timer *tmr, u32 nsec, struct nvkm_alarm *alarm) 
			if (list->timestamp > alarm->timestamp)

				break;

		}



		list_add_tail(&alarm->head, &list->head);



		/* Update HW if this is now the earliest alarm. */

		list = list_first_entry(&tmr->alarms, typeof(*list), head);

		if (list == alarm) {

			tmr->func->alarm_init(tmr, alarm->timestamp);

			/* This shouldn't happen if callers aren't stupid.

			 *

			 * Worst case scenario is that it'll take roughly

			 * 4 seconds for the next alarm to trigger.

			 */

			WARN_ON(alarm->timestamp <= nvkm_timer_read(tmr));

		}

	}

	spin_unlock_irqrestore(&tmr->lock, flags);



	/* process pending alarms */

	nvkm_timer_alarm_trigger(tmr);

}



void