Commit 26208d87 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gt: Fix hold/unhold recursion 

In eliminating the recursion from walking the tree of signalers/waiters
for processing the hold/unhold operations, a crucial error crept in
where we looked at the parent request and not the list element when
processing the list.

Brown paper bag, much?

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1166


Fixes: 32ff621f ("drm/i915/gt: Allow temporary suspension of inflight requests")
Fixes: 74831738 ("drm/i915/execlists: Offline error capture")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200209131922.180287-1-chris@chris-wilson.co.uk
parent 48d7fb18

drivers/gpu/drm/i915/gt/intel_lrc.c

+8 −5
Original line number Diff line number Diff line
@@ -2374,10 +2374,10 @@ static void __execlists_hold(struct i915_request *rq) 
		if (i915_request_is_active(rq))

			__i915_request_unsubmit(rq);



		RQ_TRACE(rq, "on hold\n");

		clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);

		list_move_tail(&rq->sched.link, &rq->engine->active.hold);

		i915_request_set_hold(rq);

		RQ_TRACE(rq, "on hold\n");



		for_each_waiter(p, rq) {

			struct i915_request *w =
@@ -2393,7 +2393,7 @@ static void __execlists_hold(struct i915_request *rq) 
			if (i915_request_completed(w))

				continue;



			if (i915_request_on_hold(rq))

			if (i915_request_on_hold(w))

				continue;



			list_move_tail(&w->sched.link, &list);
@@ -2451,6 +2451,7 @@ static bool execlists_hold(struct intel_engine_cs *engine, 
	GEM_BUG_ON(i915_request_on_hold(rq));

	GEM_BUG_ON(rq->engine != engine);

	__execlists_hold(rq);

	GEM_BUG_ON(list_empty(&engine->active.hold));



unlock:

	spin_unlock_irq(&engine->active.lock);
@@ -2486,6 +2487,8 @@ static void __execlists_unhold(struct i915_request *rq) 
	do {

		struct i915_dependency *p;



		RQ_TRACE(rq, "hold release\n");



		GEM_BUG_ON(!i915_request_on_hold(rq));

		GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
@@ -2494,7 +2497,6 @@ static void __execlists_unhold(struct i915_request *rq) 
			       i915_sched_lookup_priolist(rq->engine,

							  rq_prio(rq)));

		set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);

		RQ_TRACE(rq, "hold release\n");



		/* Also release any children on this engine that are ready */

		for_each_waiter(p, rq) {
@@ -2504,11 +2506,11 @@ static void __execlists_unhold(struct i915_request *rq) 
			if (w->engine != rq->engine)

				continue;



			if (!i915_request_on_hold(rq))

			if (!i915_request_on_hold(w))

				continue;



			/* Check that no other parents are also on hold */

			if (hold_request(rq))

			if (hold_request(w))

				continue;



			list_move_tail(&w->sched.link, &list);
@@ -2806,6 +2808,7 @@ static void execlists_submit_request(struct i915_request *request) 
	spin_lock_irqsave(&engine->active.lock, flags);



	if (unlikely(ancestor_on_hold(engine, request))) {

		RQ_TRACE(request, "ancestor on hold\n");

		list_add_tail(&request->sched.link, &engine->active.hold);

		i915_request_set_hold(request);

	} else {

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