From 26208d876d372566264bb8be76beeb0bbbcdead8 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 9 Feb 2020 13:19:15 +0000 Subject: [PATCH] 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: 32ff621fd744 ("drm/i915/gt: Allow temporary suspension of inflight requests") Fixes: 748317386afb ("drm/i915/execlists: Offline error capture") Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Tvrtko Ursulin Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20200209131922.180287-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/intel_lrc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 4bedc66..2138507 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -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 { -- 2.7.4