1 files changed, 401 insertions, 93 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 0cf0f6fae675..31455eceeb0c 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -237,7 +237,8 @@ static void execlists_init_reg_state(u32 *reg_state,
 				     bool close);
 static void
 __execlists_update_reg_state(const struct intel_context *ce,
-			     const struct intel_engine_cs *engine);
+			     const struct intel_engine_cs *engine,
+			     u32 head);
 
 static void mark_eio(struct i915_request *rq)
 {
@@ -985,6 +986,8 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine)
 			GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
 
 			list_move(&rq->sched.link, pl);
+			set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
+
 			active = rq;
 		} else {
 			struct intel_engine_cs *owner = rq->context->engine;
@@ -1184,12 +1187,11 @@ static void reset_active(struct i915_request *rq,
 		head = rq->tail;
 	else
 		head = active_request(ce->timeline, rq)->head;
-	ce->ring->head = intel_ring_wrap(ce->ring, head);
-	intel_ring_update_space(ce->ring);
+	head = intel_ring_wrap(ce->ring, head);
 
 	/* Scrub the context image to prevent replaying the previous batch */
 	restore_default_state(ce, engine);
-	__execlists_update_reg_state(ce, engine);
+	__execlists_update_reg_state(ce, engine, head);
 
 	/* We've switched away, so this should be a no-op, but intent matters */
 	ce->lrc_desc |= CTX_DESC_FORCE_RESTORE;
@@ -1319,7 +1321,7 @@ static u64 execlists_update_context(struct i915_request *rq)
 {
 	struct intel_context *ce = rq->context;
 	u64 desc = ce->lrc_desc;
-	u32 tail;
+	u32 tail, prev;
 
 	/*
 	 * WaIdleLiteRestore:bdw,skl
@@ -1332,9 +1334,15 @@ static u64 execlists_update_context(struct i915_request *rq)
 	 * subsequent resubmissions (for lite restore). Should that fail us,
 	 * and we try and submit the same tail again, force the context
 	 * reload.
+	 *
+	 * If we need to return to a preempted context, we need to skip the
+	 * lite-restore and force it to reload the RING_TAIL. Otherwise, the
+	 * HW has a tendency to ignore us rewinding the TAIL to the end of
+	 * an earlier request.
 	 */
 	tail = intel_ring_set_tail(rq->ring, rq->tail);
-	if (unlikely(ce->lrc_reg_state[CTX_RING_TAIL] == tail))
+	prev = ce->lrc_reg_state[CTX_RING_TAIL];
+	if (unlikely(intel_ring_direction(rq->ring, tail, prev) <= 0))
 		desc |= CTX_DESC_FORCE_RESTORE;
 	ce->lrc_reg_state[CTX_RING_TAIL] = tail;
 	rq->tail = rq->wa_tail;
@@ -1535,7 +1543,8 @@ static bool can_merge_rq(const struct i915_request *prev,
 		return true;
 
 	if (unlikely((prev->fence.flags ^ next->fence.flags) &
-		     (I915_FENCE_FLAG_NOPREEMPT | I915_FENCE_FLAG_SENTINEL)))
+		     (BIT(I915_FENCE_FLAG_NOPREEMPT) |
+		      BIT(I915_FENCE_FLAG_SENTINEL))))
 		return false;
 
 	if (!can_merge_ctx(prev->context, next->context))
@@ -1591,16 +1600,10 @@ static void virtual_xfer_breadcrumbs(struct virtual_engine *ve,
 	spin_unlock(&old->breadcrumbs.irq_lock);
 }
 
-static struct i915_request *
-last_active(const struct intel_engine_execlists *execlists)
-{
-	struct i915_request * const *last = READ_ONCE(execlists->active);
-
-	while (*last && i915_request_completed(*last))
-		last++;
-
-	return *last;
-}
+#define for_each_waiter(p__, rq__) \
+	list_for_each_entry_lockless(p__, \
+				     &(rq__)->sched.waiters_list, \
+				     wait_link)
 
 static void defer_request(struct i915_request *rq, struct list_head * const pl)
 {
@@ -1619,7 +1622,7 @@ static void defer_request(struct i915_request *rq, struct list_head * const pl)
 		GEM_BUG_ON(i915_request_is_active(rq));
 		list_move_tail(&rq->sched.link, pl);
 
-		list_for_each_entry(p, &rq->sched.waiters_list, wait_link) {
+		for_each_waiter(p, rq) {
 			struct i915_request *w =
 				container_of(p->waiter, typeof(*w), sched);
 
@@ -1632,8 +1635,8 @@ static void defer_request(struct i915_request *rq, struct list_head * const pl)
 				   !i915_request_completed(rq));
 
 			GEM_BUG_ON(i915_request_is_active(w));
-			if (list_empty(&w->sched.link))
-				continue; /* Not yet submitted; unready */
+			if (!i915_request_is_ready(w))
+				continue;
 
 			if (rq_prio(w) < rq_prio(rq))
 				continue;
@@ -1665,11 +1668,9 @@ need_timeslice(struct intel_engine_cs *engine, const struct i915_request *rq)
 	if (!intel_engine_has_timeslices(engine))
 		return false;
 
-	if (list_is_last(&rq->sched.link, &engine->active.requests))
-		return false;
-
-	hint = max(rq_prio(list_next_entry(rq, sched.link)),
-		   engine->execlists.queue_priority_hint);
+	hint = engine->execlists.queue_priority_hint;
+	if (!list_is_last(&rq->sched.link, &engine->active.requests))
+		hint = max(hint, rq_prio(list_next_entry(rq, sched.link)));
 
 	return hint >= effective_prio(rq);
 }
@@ -1711,16 +1712,26 @@ static void set_timeslice(struct intel_engine_cs *engine)
 	set_timer_ms(&engine->execlists.timer, active_timeslice(engine));
 }
 
+static void start_timeslice(struct intel_engine_cs *engine)
+{
+	struct intel_engine_execlists *execlists = &engine->execlists;
+
+	execlists->switch_priority_hint = execlists->queue_priority_hint;
+
+	if (timer_pending(&execlists->timer))
+		return;
+
+	set_timer_ms(&execlists->timer, timeslice(engine));
+}
+
 static void record_preemption(struct intel_engine_execlists *execlists)
 {
 	(void)I915_SELFTEST_ONLY(execlists->preempt_hang.count++);
 }
 
-static unsigned long active_preempt_timeout(struct intel_engine_cs *engine)
+static unsigned long active_preempt_timeout(struct intel_engine_cs *engine,
+					    const struct i915_request *rq)
 {
-	struct i915_request *rq;
-
-	rq = last_active(&engine->execlists);
 	if (!rq)
 		return 0;
 
@@ -1731,13 +1742,14 @@ static unsigned long active_preempt_timeout(struct intel_engine_cs *engine)
 	return READ_ONCE(engine->props.preempt_timeout_ms);
 }
 
-static void set_preempt_timeout(struct intel_engine_cs *engine)
+static void set_preempt_timeout(struct intel_engine_cs *engine,
+				const struct i915_request *rq)
 {
 	if (!intel_engine_has_preempt_reset(engine))
 		return;
 
 	set_timer_ms(&engine->execlists.preempt,
-		     active_preempt_timeout(engine));
+		     active_preempt_timeout(engine, rq));
 }
 
 static inline void clear_ports(struct i915_request **ports, int count)
@@ -1750,6 +1762,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 	struct intel_engine_execlists * const execlists = &engine->execlists;
 	struct i915_request **port = execlists->pending;
 	struct i915_request ** const last_port = port + execlists->port_mask;
+	struct i915_request * const *active;
 	struct i915_request *last;
 	struct rb_node *rb;
 	bool submit = false;
@@ -1804,7 +1817,10 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 	 * i.e. we will retrigger preemption following the ack in case
 	 * of trouble.
 	 */
-	last = last_active(execlists);
+	active = READ_ONCE(execlists->active);
+	while ((last = *active) && i915_request_completed(last))
+		active++;
+
 	if (last) {
 		if (need_preempt(engine, last, rb)) {
 			ENGINE_TRACE(engine,
@@ -1831,14 +1847,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 			 */
 			__unwind_incomplete_requests(engine);
 
-			/*
-			 * If we need to return to the preempted context, we
-			 * need to skip the lite-restore and force it to
-			 * reload the RING_TAIL. Otherwise, the HW has a
-			 * tendency to ignore us rewinding the TAIL to the
-			 * end of an earlier request.
-			 */
-			last->context->lrc_desc |= CTX_DESC_FORCE_RESTORE;
 			last = NULL;
 		} else if (need_timeslice(engine, last) &&
 			   timer_expired(&engine->execlists.timer)) {
@@ -1882,11 +1890,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 				 * Even if ELSP[1] is occupied and not worthy
 				 * of timeslices, our queue might be.
 				 */
-				if (!execlists->timer.expires &&
-				    need_timeslice(engine, last))
-					set_timer_ms(&execlists->timer,
-						     timeslice(engine));
-
+				start_timeslice(engine);
 				return;
 			}
 		}
@@ -1921,7 +1925,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 
 			if (last && !can_merge_rq(last, rq)) {
 				spin_unlock(&ve->base.active.lock);
-				return; /* leave this for another */
+				start_timeslice(engine);
+				return; /* leave this for another sibling */
 			}
 
 			ENGINE_TRACE(engine,
@@ -2097,7 +2102,7 @@ done:
 		 * Skip if we ended up with exactly the same set of requests,
 		 * e.g. trying to timeslice a pair of ordered contexts
 		 */
-		if (!memcmp(execlists->active, execlists->pending,
+		if (!memcmp(active, execlists->pending,
 			    (port - execlists->pending + 1) * sizeof(*port))) {
 			do
 				execlists_schedule_out(fetch_and_zero(port));
@@ -2108,7 +2113,7 @@ done:
 		clear_ports(port + 1, last_port - port);
 
 		execlists_submit_ports(engine);
-		set_preempt_timeout(engine);
+		set_preempt_timeout(engine, *active);
 	} else {
 skip_submit:
 		ring_set_paused(engine, 0);
@@ -2351,6 +2356,310 @@ static void __execlists_submission_tasklet(struct intel_engine_cs *const engine)
 	}
 }
 
+static void __execlists_hold(struct i915_request *rq)
+{
+	LIST_HEAD(list);
+
+	do {
+		struct i915_dependency *p;
+
+		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);
+
+		list_for_each_entry(p, &rq->sched.waiters_list, wait_link) {
+			struct i915_request *w =
+				container_of(p->waiter, typeof(*w), sched);
+
+			/* Leave semaphores spinning on the other engines */
+			if (w->engine != rq->engine)
+				continue;
+
+			if (!i915_request_is_ready(w))
+				continue;
+
+			if (i915_request_completed(w))
+				continue;
+
+			if (i915_request_on_hold(rq))
+				continue;
+
+			list_move_tail(&w->sched.link, &list);
+		}
+
+		rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
+	} while (rq);
+}
+
+static bool execlists_hold(struct intel_engine_cs *engine,
+			   struct i915_request *rq)
+{
+	spin_lock_irq(&engine->active.lock);
+
+	if (i915_request_completed(rq)) { /* too late! */
+		rq = NULL;
+		goto unlock;
+	}
+
+	if (rq->engine != engine) { /* preempted virtual engine */
+		struct virtual_engine *ve = to_virtual_engine(rq->engine);
+
+		/*
+		 * intel_context_inflight() is only protected by virtue
+		 * of process_csb() being called only by the tasklet (or
+		 * directly from inside reset while the tasklet is suspended).
+		 * Assert that neither of those are allowed to run while we
+		 * poke at the request queues.
+		 */
+		GEM_BUG_ON(!reset_in_progress(&engine->execlists));
+
+		/*
+		 * An unsubmitted request along a virtual engine will
+		 * remain on the active (this) engine until we are able
+		 * to process the context switch away (and so mark the
+		 * context as no longer in flight). That cannot have happened
+		 * yet, otherwise we would not be hanging!
+		 */
+		spin_lock(&ve->base.active.lock);
+		GEM_BUG_ON(intel_context_inflight(rq->context) != engine);
+		GEM_BUG_ON(ve->request != rq);
+		ve->request = NULL;
+		spin_unlock(&ve->base.active.lock);
+		i915_request_put(rq);
+
+		rq->engine = engine;
+	}
+
+	/*
+	 * Transfer this request onto the hold queue to prevent it
+	 * being resumbitted to HW (and potentially completed) before we have
+	 * released it. Since we may have already submitted following
+	 * requests, we need to remove those as well.
+	 */
+	GEM_BUG_ON(i915_request_on_hold(rq));
+	GEM_BUG_ON(rq->engine != engine);
+	__execlists_hold(rq);
+
+unlock:
+	spin_unlock_irq(&engine->active.lock);
+	return rq;
+}
+
+static bool hold_request(const struct i915_request *rq)
+{
+	struct i915_dependency *p;
+
+	/*
+	 * If one of our ancestors is on hold, we must also be on hold,
+	 * otherwise we will bypass it and execute before it.
+	 */
+	list_for_each_entry(p, &rq->sched.signalers_list, signal_link) {
+		const struct i915_request *s =
+			container_of(p->signaler, typeof(*s), sched);
+
+		if (s->engine != rq->engine)
+			continue;
+
+		if (i915_request_on_hold(s))
+			return true;
+	}
+
+	return false;
+}
+
+static void __execlists_unhold(struct i915_request *rq)
+{
+	LIST_HEAD(list);
+
+	do {
+		struct i915_dependency *p;
+
+		GEM_BUG_ON(!i915_request_on_hold(rq));
+		GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
+
+		i915_request_clear_hold(rq);
+		list_move_tail(&rq->sched.link,
+			       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 */
+		list_for_each_entry(p, &rq->sched.waiters_list, wait_link) {
+			struct i915_request *w =
+				container_of(p->waiter, typeof(*w), sched);
+
+			if (w->engine != rq->engine)
+				continue;
+
+			if (!i915_request_on_hold(rq))
+				continue;
+
+			/* Check that no other parents are also on hold */
+			if (hold_request(rq))
+				continue;
+
+			list_move_tail(&w->sched.link, &list);
+		}
+
+		rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
+	} while (rq);
+}
+
+static void execlists_unhold(struct intel_engine_cs *engine,
+			     struct i915_request *rq)
+{
+	spin_lock_irq(&engine->active.lock);
+
+	/*
+	 * Move this request back to the priority queue, and all of its
+	 * children and grandchildren that were suspended along with it.
+	 */
+	__execlists_unhold(rq);
+
+	if (rq_prio(rq) > engine->execlists.queue_priority_hint) {
+		engine->execlists.queue_priority_hint = rq_prio(rq);
+		tasklet_hi_schedule(&engine->execlists.tasklet);
+	}
+
+	spin_unlock_irq(&engine->active.lock);
+}
+
+struct execlists_capture {
+	struct work_struct work;
+	struct i915_request *rq;
+	struct i915_gpu_coredump *error;
+};
+
+static void execlists_capture_work(struct work_struct *work)
+{
+	struct execlists_capture *cap = container_of(work, typeof(*cap), work);
+	const gfp_t gfp = GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
+	struct intel_engine_cs *engine = cap->rq->engine;
+	struct intel_gt_coredump *gt = cap->error->gt;
+	struct intel_engine_capture_vma *vma;
+
+	/* Compress all the objects attached to the request, slow! */
+	vma = intel_engine_coredump_add_request(gt->engine, cap->rq, gfp);
+	if (vma) {
+		struct i915_vma_compress *compress =
+			i915_vma_capture_prepare(gt);
+
+		intel_engine_coredump_add_vma(gt->engine, vma, compress);
+		i915_vma_capture_finish(gt, compress);
+	}
+
+	gt->simulated = gt->engine->simulated;
+	cap->error->simulated = gt->simulated;
+
+	/* Publish the error state, and announce it to the world */
+	i915_error_state_store(cap->error);
+	i915_gpu_coredump_put(cap->error);
+
+	/* Return this request and all that depend upon it for signaling */
+	execlists_unhold(engine, cap->rq);
+	i915_request_put(cap->rq);
+
+	kfree(cap);
+}
+
+static struct execlists_capture *capture_regs(struct intel_engine_cs *engine)
+{
+	const gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN;
+	struct execlists_capture *cap;
+
+	cap = kmalloc(sizeof(*cap), gfp);
+	if (!cap)
+		return NULL;
+
+	cap->error = i915_gpu_coredump_alloc(engine->i915, gfp);
+	if (!cap->error)
+		goto err_cap;
+
+	cap->error->gt = intel_gt_coredump_alloc(engine->gt, gfp);
+	if (!cap->error->gt)
+		goto err_gpu;
+
+	cap->error->gt->engine = intel_engine_coredump_alloc(engine, gfp);
+	if (!cap->error->gt->engine)
+		goto err_gt;
+
+	return cap;
+
+err_gt:
+	kfree(cap->error->gt);
+err_gpu:
+	kfree(cap->error);
+err_cap:
+	kfree(cap);
+	return NULL;
+}
+
+static bool execlists_capture(struct intel_engine_cs *engine)
+{
+	struct execlists_capture *cap;
+
+	if (!IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR))
+		return true;
+
+	/*
+	 * We need to _quickly_ capture the engine state before we reset.
+	 * We are inside an atomic section (softirq) here and we are delaying
+	 * the forced preemption event.
+	 */
+	cap = capture_regs(engine);
+	if (!cap)
+		return true;
+
+	cap->rq = execlists_active(&engine->execlists);
+	GEM_BUG_ON(!cap->rq);
+
+	rcu_read_lock();
+	cap->rq = active_request(cap->rq->context->timeline, cap->rq);
+	cap->rq = i915_request_get_rcu(cap->rq);
+	rcu_read_unlock();
+	if (!cap->rq)
+		goto err_free;
+
+	/*
+	 * Remove the request from the execlists queue, and take ownership
+	 * of the request. We pass it to our worker who will _slowly_ compress
+	 * all the pages the _user_ requested for debugging their batch, after
+	 * which we return it to the queue for signaling.
+	 *
+	 * By removing them from the execlists queue, we also remove the
+	 * requests from being processed by __unwind_incomplete_requests()
+	 * during the intel_engine_reset(), and so they will *not* be replayed
+	 * afterwards.
+	 *
+	 * Note that because we have not yet reset the engine at this point,
+	 * it is possible for the request that we have identified as being
+	 * guilty, did in fact complete and we will then hit an arbitration
+	 * point allowing the outstanding preemption to succeed. The likelihood
+	 * of that is very low (as capturing of the engine registers should be
+	 * fast enough to run inside an irq-off atomic section!), so we will
+	 * simply hold that request accountable for being non-preemptible
+	 * long enough to force the reset.
+	 */
+	if (!execlists_hold(engine, cap->rq))
+		goto err_rq;
+
+	INIT_WORK(&cap->work, execlists_capture_work);
+	schedule_work(&cap->work);
+	return true;
+
+err_rq:
+	i915_request_put(cap->rq);
+err_free:
+	i915_gpu_coredump_put(cap->error);
+	kfree(cap);
+	return false;
+}
+
 static noinline void preempt_reset(struct intel_engine_cs *engine)
 {
 	const unsigned int bit = I915_RESET_ENGINE + engine->id;
@@ -2368,7 +2677,12 @@ static noinline void preempt_reset(struct intel_engine_cs *engine)
 	ENGINE_TRACE(engine, "preempt timeout %lu+%ums\n",
 		     READ_ONCE(engine->props.preempt_timeout_ms),
 		     jiffies_to_msecs(jiffies - engine->execlists.preempt.expires));
-	intel_engine_reset(engine, "preemption time out");
+
+	ring_set_paused(engine, 1); /* Freeze the current request in place */
+	if (execlists_capture(engine))
+		intel_engine_reset(engine, "preemption time out");
+	else
+		ring_set_paused(engine, 0);
 
 	tasklet_enable(&engine->execlists.tasklet);
 	clear_and_wake_up_bit(bit, lock);
@@ -2430,11 +2744,12 @@ static void execlists_preempt(struct timer_list *timer)
 }
 
 static void queue_request(struct intel_engine_cs *engine,
-			  struct i915_sched_node *node,
-			  int prio)
+			  struct i915_request *rq)
 {
-	GEM_BUG_ON(!list_empty(&node->link));
-	list_add_tail(&node->link, i915_sched_lookup_priolist(engine, prio));
+	GEM_BUG_ON(!list_empty(&rq->sched.link));
+	list_add_tail(&rq->sched.link,
+		      i915_sched_lookup_priolist(engine, rq_prio(rq)));
+	set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
 }
 
 static void __submit_queue_imm(struct intel_engine_cs *engine)
@@ -2462,6 +2777,13 @@ static void submit_queue(struct intel_engine_cs *engine,
 	__submit_queue_imm(engine);
 }
 
+static bool ancestor_on_hold(const struct intel_engine_cs *engine,
+			     const struct i915_request *rq)
+{
+	GEM_BUG_ON(i915_request_on_hold(rq));
+	return !list_empty(&engine->active.hold) && hold_request(rq);
+}
+
 static void execlists_submit_request(struct i915_request *request)
 {
 	struct intel_engine_cs *engine = request->engine;
@@ -2470,12 +2792,17 @@ static void execlists_submit_request(struct i915_request *request)
 	/* Will be called from irq-context when using foreign fences. */
 	spin_lock_irqsave(&engine->active.lock, flags);
 
-	queue_request(engine, &request->sched, rq_prio(request));
+	if (unlikely(ancestor_on_hold(engine, request))) {
+		list_add_tail(&request->sched.link, &engine->active.hold);
+		i915_request_set_hold(request);
+	} else {
+		queue_request(engine, request);
 
-	GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
-	GEM_BUG_ON(list_empty(&request->sched.link));
+		GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
+		GEM_BUG_ON(list_empty(&request->sched.link));
 
-	submit_queue(engine, request);
+		submit_queue(engine, request);
+	}
 
 	spin_unlock_irqrestore(&engine->active.lock, flags);
 }
@@ -2531,21 +2858,21 @@ static void execlists_context_unpin(struct intel_context *ce)
 		      ce->engine);
 
 	i915_gem_object_unpin_map(ce->state->obj);
-	intel_ring_reset(ce->ring, ce->ring->tail);
 }
 
 static void
 __execlists_update_reg_state(const struct intel_context *ce,
-			     const struct intel_engine_cs *engine)
+			     const struct intel_engine_cs *engine,
+			     u32 head)
 {
 	struct intel_ring *ring = ce->ring;
 	u32 *regs = ce->lrc_reg_state;
 
-	GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->head));
+	GEM_BUG_ON(!intel_ring_offset_valid(ring, head));
 	GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->tail));
 
 	regs[CTX_RING_START] = i915_ggtt_offset(ring->vma);
-	regs[CTX_RING_HEAD] = ring->head;
+	regs[CTX_RING_HEAD] = head;
 	regs[CTX_RING_TAIL] = ring->tail;
 
 	/* RPCS */
@@ -2574,7 +2901,7 @@ __execlists_context_pin(struct intel_context *ce,
 
 	ce->lrc_desc = lrc_descriptor(ce, engine) | CTX_DESC_FORCE_RESTORE;
 	ce->lrc_reg_state = vaddr + LRC_STATE_PN * PAGE_SIZE;
-	__execlists_update_reg_state(ce, engine);
+	__execlists_update_reg_state(ce, engine, ce->ring->tail);
 
 	return 0;
 }
@@ -2615,7 +2942,7 @@ static void execlists_context_reset(struct intel_context *ce)
 	/* Scrub away the garbage */
 	execlists_init_reg_state(ce->lrc_reg_state,
 				 ce, ce->engine, ce->ring, true);
-	__execlists_update_reg_state(ce, ce->engine);
+	__execlists_update_reg_state(ce, ce->engine, ce->ring->tail);
 
 	ce->lrc_desc |= CTX_DESC_FORCE_RESTORE;
 }
@@ -3170,6 +3497,7 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
 	struct intel_engine_execlists * const execlists = &engine->execlists;
 	struct intel_context *ce;
 	struct i915_request *rq;
+	u32 head;
 
 	mb(); /* paranoia: read the CSB pointers from after the reset */
 	clflush(execlists->csb_write);
@@ -3197,15 +3525,15 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
 
 	if (i915_request_completed(rq)) {
 		/* Idle context; tidy up the ring so we can restart afresh */
-		ce->ring->head = intel_ring_wrap(ce->ring, rq->tail);
+		head = intel_ring_wrap(ce->ring, rq->tail);
 		goto out_replay;
 	}
 
 	/* Context has requests still in-flight; it should not be idle! */
 	GEM_BUG_ON(i915_active_is_idle(&ce->active));
 	rq = active_request(ce->timeline, rq);
-	ce->ring->head = intel_ring_wrap(ce->ring, rq->head);
-	GEM_BUG_ON(ce->ring->head == ce->ring->tail);
+	head = intel_ring_wrap(ce->ring, rq->head);
+	GEM_BUG_ON(head == ce->ring->tail);
 
 	/*
 	 * If this request hasn't started yet, e.g. it is waiting on a
@@ -3250,10 +3578,9 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
 
 out_replay:
 	ENGINE_TRACE(engine, "replay {head:%04x, tail:%04x}\n",
-		     ce->ring->head, ce->ring->tail);
-	intel_ring_update_space(ce->ring);
+		     head, ce->ring->tail);
 	__execlists_reset_reg_state(ce, engine);
-	__execlists_update_reg_state(ce, engine);
+	__execlists_update_reg_state(ce, engine, head);
 	ce->lrc_desc |= CTX_DESC_FORCE_RESTORE; /* paranoid: GPU was reset! */
 
 unwind:
@@ -3325,6 +3652,10 @@ static void execlists_reset_cancel(struct intel_engine_cs *engine)
 		i915_priolist_free(p);
 	}
 
+	/* On-hold requests will be flushed to timeline upon their release */
+	list_for_each_entry(rq, &engine->active.hold, sched.link)
+		mark_eio(rq);
+
 	/* Cancel all attached virtual engines */
 	while ((rb = rb_first_cached(&execlists->virtual))) {
 		struct virtual_engine *ve =
@@ -3669,26 +4000,6 @@ static int gen12_emit_flush_render(struct i915_request *request,
 
 		*cs++ = preparser_disable(false);
 		intel_ring_advance(request, cs);
-
-		/*
-		 * Wa_1604544889:tgl
-		 */
-		if (IS_TGL_REVID(request->i915, TGL_REVID_A0, TGL_REVID_A0)) {
-			flags = 0;
-			flags |= PIPE_CONTROL_CS_STALL;
-			flags |= PIPE_CONTROL_HDC_PIPELINE_FLUSH;
-
-			flags |= PIPE_CONTROL_STORE_DATA_INDEX;
-			flags |= PIPE_CONTROL_QW_WRITE;
-
-			cs = intel_ring_begin(request, 6);
-			if (IS_ERR(cs))
-				return PTR_ERR(cs);
-
-			cs = gen8_emit_pipe_control(cs, flags,
-						    LRC_PPHWSP_SCRATCH_ADDR);
-			intel_ring_advance(request, cs);
-		}
 	}
 
 	return 0;
@@ -4892,10 +5203,7 @@ void intel_lr_context_reset(struct intel_engine_cs *engine,
 		restore_default_state(ce, engine);
 
 	/* Rerun the request; its payload has been neutered (if guilty). */
-	ce->ring->head = head;
-	intel_ring_update_space(ce->ring);
-
-	__execlists_update_reg_state(ce, engine);
+	__execlists_update_reg_state(ce, engine, head);
 }
 
 bool