Merge tag 'drm-intel-fixes-2020-02-20' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

drm/i915 fixes for v5.6-rc3:
- Workaround missing Display Stream Compression (DSC) state readout by
  forcing modeset when its enabled at probe
- Fix EHL port clock voltage level requirements
- Fix queuing retire workers on the virtual engine
- Fix use of partially initialized waiters
- Stop using drm_pci_alloc/drm_pci/free
- Fix rewind of RING_TAIL by forcing a context reload
- Fix locking on resetting ring->head
- Propagate our bug filing URL change to stable kernels

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/87y2sxtsrd.fsf@intel.com

MAINTAINERS

@@ -8392,7 +8392,7 @@ M:	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
 M:	Rodrigo Vivi <rodrigo.vivi@intel.com>
 L:	intel-gfx@lists.freedesktop.org
 W:	https://01.org/linuxgraphics/
-B:	https://01.org/linuxgraphics/documentation/how-report-bugs
+B:	https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs
 C:	irc://chat.freenode.net/intel-gfx
 Q:	http://patchwork.freedesktop.org/project/intel-gfx/
 T:	git git://anongit.freedesktop.org/drm-intel

drivers/gpu/drm/i915/Kconfig

@@ -75,9 +75,8 @@ config DRM_I915_CAPTURE_ERROR
 	help
 	  This option enables capturing the GPU state when a hang is detected.
 	  This information is vital for triaging hangs and assists in debugging.
-	  Please report any hang to
+	  Please report any hang for triaging according to:
-	    https://bugs.freedesktop.org/enter_bug.cgi?product=DRI
+	    https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs
-	  for triaging.
 
 	  If in doubt, say "Y".
 

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -4251,7 +4251,9 @@ static bool intel_ddi_is_audio_enabled(struct drm_i915_private *dev_priv,
 void intel_ddi_compute_min_voltage_level(struct drm_i915_private *dev_priv,
 					 struct intel_crtc_state *crtc_state)
 {
-	if (INTEL_GEN(dev_priv) >= 11 && crtc_state->port_clock > 594000)
+	if (IS_ELKHARTLAKE(dev_priv) && crtc_state->port_clock > 594000)
+		crtc_state->min_voltage_level = 3;
+	else if (INTEL_GEN(dev_priv) >= 11 && crtc_state->port_clock > 594000)
 		crtc_state->min_voltage_level = 1;
 	else if (IS_CANNONLAKE(dev_priv) && crtc_state->port_clock > 594000)
 		crtc_state->min_voltage_level = 2;

drivers/gpu/drm/i915/display/intel_display.c

@@ -11087,7 +11087,7 @@ static u32 intel_cursor_base(const struct intel_plane_state *plane_state)
 	u32 base;
 
 	if (INTEL_INFO(dev_priv)->display.cursor_needs_physical)
-		base = obj->phys_handle->busaddr;
+		base = sg_dma_address(obj->mm.pages->sgl);
 	else
 		base = intel_plane_ggtt_offset(plane_state);
 
@@ -17433,6 +17433,24 @@ static int intel_initial_commit(struct drm_device *dev)
 			 * have readout for pipe gamma enable.
 			 */
 			crtc_state->uapi.color_mgmt_changed = true;
+
+			/*
+			 * FIXME hack to force full modeset when DSC is being
+			 * used.
+			 *
+			 * As long as we do not have full state readout and
+			 * config comparison of crtc_state->dsc, we have no way
+			 * to ensure reliable fastset. Remove once we have
+			 * readout for DSC.
+			 */
+			if (crtc_state->dsc.compression_enable) {
+				ret = drm_atomic_add_affected_connectors(state,
+									 &crtc->base);
+				if (ret)
+					goto out;
+				crtc_state->uapi.mode_changed = true;
+				drm_dbg_kms(dev, "Force full modeset for DSC\n");
+			}
 		}
 	}
 

drivers/gpu/drm/i915/gem/i915_gem_context.c

@@ -565,6 +565,22 @@ static int __context_set_persistence(struct i915_gem_context *ctx, bool state)
 		if (!(ctx->i915->caps.scheduler & I915_SCHEDULER_CAP_PREEMPTION))
 			return -ENODEV;
 
+		/*
+		 * If the cancel fails, we then need to reset, cleanly!
+		 *
+		 * If the per-engine reset fails, all hope is lost! We resort
+		 * to a full GPU reset in that unlikely case, but realistically
+		 * if the engine could not reset, the full reset does not fare
+		 * much better. The damage has been done.
+		 *
+		 * However, if we cannot reset an engine by itself, we cannot
+		 * cleanup a hanging persistent context without causing
+		 * colateral damage, and we should not pretend we can by
+		 * exposing the interface.
+		 */
+		if (!intel_has_reset_engine(&ctx->i915->gt))
+			return -ENODEV;
+
 		i915_gem_context_clear_persistence(ctx);
 	}
 

drivers/gpu/drm/i915/gem/i915_gem_object_types.h

@@ -285,9 +285,6 @@ struct drm_i915_gem_object {
 
 		void *gvt_info;
 	};
-
-	/** for phys allocated objects */
-	struct drm_dma_handle *phys_handle;
 };
 
 static inline struct drm_i915_gem_object *

drivers/gpu/drm/i915/gem/i915_gem_phys.c

@@ -22,88 +22,87 @@
 static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
 {
 	struct address_space *mapping = obj->base.filp->f_mapping;
-	struct drm_dma_handle *phys;
-	struct sg_table *st;
 	struct scatterlist *sg;
-	char *vaddr;
+	struct sg_table *st;
+	dma_addr_t dma;
+	void *vaddr;
+	void *dst;
 	int i;
-	int err;
 
 	if (WARN_ON(i915_gem_object_needs_bit17_swizzle(obj)))
 		return -EINVAL;
 
-	/* Always aligning to the object size, allows a single allocation
+	/*
+	 * Always aligning to the object size, allows a single allocation
 	 * to handle all possible callers, and given typical object sizes,
 	 * the alignment of the buddy allocation will naturally match.
 	 */
-	phys = drm_pci_alloc(obj->base.dev,
+	vaddr = dma_alloc_coherent(&obj->base.dev->pdev->dev,
-			     roundup_pow_of_two(obj->base.size),
+				   roundup_pow_of_two(obj->base.size),
-			     roundup_pow_of_two(obj->base.size));
+				   &dma, GFP_KERNEL);
-	if (!phys)
+	if (!vaddr)
 		return -ENOMEM;
 
-	vaddr = phys->vaddr;
-	for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
-		struct page *page;
-		char *src;
-
-		page = shmem_read_mapping_page(mapping, i);
-		if (IS_ERR(page)) {
-			err = PTR_ERR(page);
-			goto err_phys;
-		}
-
-		src = kmap_atomic(page);
-		memcpy(vaddr, src, PAGE_SIZE);
-		drm_clflush_virt_range(vaddr, PAGE_SIZE);
-		kunmap_atomic(src);
-
-		put_page(page);
-		vaddr += PAGE_SIZE;
-	}
-
-	intel_gt_chipset_flush(&to_i915(obj->base.dev)->gt);
-
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
-	if (!st) {
+	if (!st)
-		err = -ENOMEM;
+		goto err_pci;
-		goto err_phys;
-	}
 
-	if (sg_alloc_table(st, 1, GFP_KERNEL)) {
+	if (sg_alloc_table(st, 1, GFP_KERNEL))
-		kfree(st);
+		goto err_st;
-		err = -ENOMEM;
-		goto err_phys;
-	}
 
 	sg = st->sgl;
 	sg->offset = 0;
 	sg->length = obj->base.size;
 
-	sg_dma_address(sg) = phys->busaddr;
+	sg_assign_page(sg, (struct page *)vaddr);
+	sg_dma_address(sg) = dma;
 	sg_dma_len(sg) = obj->base.size;
 
-	obj->phys_handle = phys;
+	dst = vaddr;
+	for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
+		struct page *page;
+		void *src;
+
+		page = shmem_read_mapping_page(mapping, i);
+		if (IS_ERR(page))
+			goto err_st;
+
+		src = kmap_atomic(page);
+		memcpy(dst, src, PAGE_SIZE);
+		drm_clflush_virt_range(dst, PAGE_SIZE);
+		kunmap_atomic(src);
+
+		put_page(page);
+		dst += PAGE_SIZE;
+	}
+
+	intel_gt_chipset_flush(&to_i915(obj->base.dev)->gt);
 
 	__i915_gem_object_set_pages(obj, st, sg->length);
 
 	return 0;
 
-err_phys:
+err_st:
-	drm_pci_free(obj->base.dev, phys);
+	kfree(st);
-
+err_pci:
-	return err;
+	dma_free_coherent(&obj->base.dev->pdev->dev,
+			  roundup_pow_of_two(obj->base.size),
+			  vaddr, dma);
+	return -ENOMEM;
 }
 
 static void
 i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
 			       struct sg_table *pages)
 {
+	dma_addr_t dma = sg_dma_address(pages->sgl);
+	void *vaddr = sg_page(pages->sgl);
+
 	__i915_gem_object_release_shmem(obj, pages, false);
 
 	if (obj->mm.dirty) {
 		struct address_space *mapping = obj->base.filp->f_mapping;
-		char *vaddr = obj->phys_handle->vaddr;
+		void *src = vaddr;
 		int i;
 
 		for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
@@ -115,15 +114,16 @@ i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
 				continue;
 
 			dst = kmap_atomic(page);
-			drm_clflush_virt_range(vaddr, PAGE_SIZE);
+			drm_clflush_virt_range(src, PAGE_SIZE);
-			memcpy(dst, vaddr, PAGE_SIZE);
+			memcpy(dst, src, PAGE_SIZE);
 			kunmap_atomic(dst);
 
 			set_page_dirty(page);
 			if (obj->mm.madv == I915_MADV_WILLNEED)
 				mark_page_accessed(page);
 			put_page(page);
-			vaddr += PAGE_SIZE;
+
+			src += PAGE_SIZE;
 		}
 		obj->mm.dirty = false;
 	}
@@ -131,7 +131,9 @@ i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
 	sg_free_table(pages);
 	kfree(pages);
 
-	drm_pci_free(obj->base.dev, obj->phys_handle);
+	dma_free_coherent(&obj->base.dev->pdev->dev,
+			  roundup_pow_of_two(obj->base.size),
+			  vaddr, dma);
 }
 
 static void phys_release(struct drm_i915_gem_object *obj)

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

@@ -136,6 +136,9 @@ static void add_retire(struct intel_breadcrumbs *b, struct intel_timeline *tl)
 	struct intel_engine_cs *engine =
 		container_of(b, struct intel_engine_cs, breadcrumbs);
 
+	if (unlikely(intel_engine_is_virtual(engine)))
+		engine = intel_virtual_engine_get_sibling(engine, 0);
+
 	intel_engine_add_retire(engine, tl);
 }
 

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

@@ -99,6 +99,9 @@ static bool add_retire(struct intel_engine_cs *engine,
 void intel_engine_add_retire(struct intel_engine_cs *engine,
 			     struct intel_timeline *tl)
 {
+	/* We don't deal well with the engine disappearing beneath us */
+	GEM_BUG_ON(intel_engine_is_virtual(engine));
+
 	if (add_retire(engine, tl))
 		schedule_work(&engine->retire_work);
 }

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)
 {
@@ -1186,12 +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);
+	head = intel_ring_wrap(ce->ring, head);
-	intel_ring_update_space(ce->ring);
 
 	/* 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;
@@ -1321,7 +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
@@ -1334,9 +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;
@@ -1605,6 +1611,11 @@ last_active(const struct intel_engine_execlists *execlists)
 	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)
 {
 	LIST_HEAD(list);
@@ -1622,7 +1633,7 @@ 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);
 
@@ -1834,14 +1845,6 @@ 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)) {
@@ -2860,16 +2863,17 @@ static void execlists_context_unpin(struct intel_context *ce)
 
 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 */
@@ -2898,7 +2902,7 @@ __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;
 }
@@ -2939,7 +2943,7 @@ 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;
 }
@@ -3494,6 +3498,7 @@ 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);
@@ -3521,15 +3526,15 @@ 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);
+	head = intel_ring_wrap(ce->ring, rq->head);
-	GEM_BUG_ON(ce->ring->head == ce->ring->tail);
+	GEM_BUG_ON(head == ce->ring->tail);
 
 	/*
 	 * If this request hasn't started yet, e.g. it is waiting on a
@@ -3574,10 +3579,9 @@ 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);
+		     head, ce->ring->tail);
-	intel_ring_update_space(ce->ring);
 	__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:
@@ -5220,10 +5224,7 @@ 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;
+	__execlists_update_reg_state(ce, engine, head);
-	intel_ring_update_space(ce->ring);
-
-	__execlists_update_reg_state(ce, engine);
 }
 
 bool

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

@@ -145,6 +145,7 @@ intel_engine_create_ring(struct intel_engine_cs *engine, int size)
 
 	kref_init(&ring->ref);
 	ring->size = size;
+	ring->wrap = BITS_PER_TYPE(ring->size) - ilog2(size);
 
 	/*
 	 * Workaround an erratum on the i830 which causes a hang if

drivers/gpu/drm/i915/gt/intel_ring.h

@@ -56,6 +56,14 @@ static inline u32 intel_ring_wrap(const struct intel_ring *ring, u32 pos)
 	return pos & (ring->size - 1);
 }
 
+static inline int intel_ring_direction(const struct intel_ring *ring,
+				       u32 next, u32 prev)
+{
+	typecheck(typeof(ring->size), next);
+	typecheck(typeof(ring->size), prev);
+	return (next - prev) << ring->wrap;
+}
+
 static inline bool
 intel_ring_offset_valid(const struct intel_ring *ring,
 			unsigned int pos)

drivers/gpu/drm/i915/gt/intel_ring_types.h

@@ -39,12 +39,13 @@ struct intel_ring {
 	 */
 	atomic_t pin_count;
 
-	u32 head;
+	u32 head; /* updated during retire, loosely tracks RING_HEAD */
-	u32 tail;
+	u32 tail; /* updated on submission, used for RING_TAIL */
-	u32 emit;
+	u32 emit; /* updated during request construction */
 
 	u32 space;
 	u32 size;
+	u32 wrap;
 	u32 effective_size;
 };
 

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

@@ -186,7 +186,7 @@ static int live_unlite_restore(struct intel_gt *gt, int prio)
 		}
 		GEM_BUG_ON(!ce[1]->ring->size);
 		intel_ring_reset(ce[1]->ring, ce[1]->ring->size / 2);
-		__execlists_update_reg_state(ce[1], engine);
+		__execlists_update_reg_state(ce[1], engine, ce[1]->ring->head);
 
 		rq[0] = igt_spinner_create_request(&spin, ce[0], MI_ARB_CHECK);
 		if (IS_ERR(rq[0])) {

drivers/gpu/drm/i915/i915_gem.c

@@ -180,7 +180,7 @@ i915_gem_phys_pwrite(struct drm_i915_gem_object *obj,
 		     struct drm_i915_gem_pwrite *args,
 		     struct drm_file *file)
 {
-	void *vaddr = obj->phys_handle->vaddr + args->offset;
+	void *vaddr = sg_page(obj->mm.pages->sgl) + args->offset;
 	char __user *user_data = u64_to_user_ptr(args->data_ptr);
 
 	/*
@@ -844,10 +844,10 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
 		ret = i915_gem_gtt_pwrite_fast(obj, args);
 
 	if (ret == -EFAULT || ret == -ENOSPC) {
-		if (obj->phys_handle)
+		if (i915_gem_object_has_struct_page(obj))
-			ret = i915_gem_phys_pwrite(obj, args, file);
-		else
 			ret = i915_gem_shmem_pwrite(obj, args);
+		else
+			ret = i915_gem_phys_pwrite(obj, args, file);
 	}
 
 	i915_gem_object_unpin_pages(obj);

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -1852,7 +1852,8 @@ void i915_error_state_store(struct i915_gpu_coredump *error)
 	if (!xchg(&warned, true) &&
 	    ktime_get_real_seconds() - DRIVER_TIMESTAMP < DAY_AS_SECONDS(180)) {
 		pr_info("GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.\n");
-		pr_info("Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel\n");
+		pr_info("Please file a _new_ bug report at https://gitlab.freedesktop.org/drm/intel/issues/new.\n");
+		pr_info("Please see https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs for details.\n");
 		pr_info("drm/i915 developers can then reassign to the right component if it's not a kernel issue.\n");
 		pr_info("The GPU crash dump is required to analyze GPU hangs, so please always attach it.\n");
 		pr_info("GPU crash dump saved to /sys/class/drm/card%d/error\n",

drivers/gpu/drm/i915/i915_request.c

@@ -595,6 +595,8 @@ static void __i915_request_ctor(void *arg)
 	i915_sw_fence_init(&rq->submit, submit_notify);
 	i915_sw_fence_init(&rq->semaphore, semaphore_notify);
 
+	dma_fence_init(&rq->fence, &i915_fence_ops, &rq->lock, 0, 0);
+
 	rq->file_priv = NULL;
 	rq->capture_list = NULL;
 
@@ -653,25 +655,30 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp)
 		}
 	}
 
-	ret = intel_timeline_get_seqno(tl, rq, &seqno);
-	if (ret)
-		goto err_free;
-
 	rq->i915 = ce->engine->i915;
 	rq->context = ce;
 	rq->engine = ce->engine;
 	rq->ring = ce->ring;
 	rq->execution_mask = ce->engine->mask;
 
+	kref_init(&rq->fence.refcount);
+	rq->fence.flags = 0;
+	rq->fence.error = 0;
+	INIT_LIST_HEAD(&rq->fence.cb_list);
+
+	ret = intel_timeline_get_seqno(tl, rq, &seqno);
+	if (ret)
+		goto err_free;
+
+	rq->fence.context = tl->fence_context;
+	rq->fence.seqno = seqno;
+
 	RCU_INIT_POINTER(rq->timeline, tl);
 	RCU_INIT_POINTER(rq->hwsp_cacheline, tl->hwsp_cacheline);
 	rq->hwsp_seqno = tl->hwsp_seqno;
 
 	rq->rcustate = get_state_synchronize_rcu(); /* acts as smp_mb() */
 
-	dma_fence_init(&rq->fence, &i915_fence_ops, &rq->lock,
-		       tl->fence_context, seqno);
-
 	/* We bump the ref for the fence chain */
 	i915_sw_fence_reinit(&i915_request_get(rq)->submit);
 	i915_sw_fence_reinit(&i915_request_get(rq)->semaphore);

drivers/gpu/drm/i915/i915_scheduler.c

@@ -423,8 +423,6 @@ bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
 
 	if (!node_signaled(signal)) {
 		INIT_LIST_HEAD(&dep->dfs_link);
-		list_add(&dep->wait_link, &signal->waiters_list);
-		list_add(&dep->signal_link, &node->signalers_list);
 		dep->signaler = signal;
 		dep->waiter = node;
 		dep->flags = flags;
@@ -434,6 +432,10 @@ bool __i915_sched_node_add_dependency(struct i915_sched_node *node,
 		    !node_started(signal))
 			node->flags |= I915_SCHED_HAS_SEMAPHORE_CHAIN;
 
+		/* All set, now publish. Beware the lockless walkers. */
+		list_add(&dep->signal_link, &node->signalers_list);
+		list_add_rcu(&dep->wait_link, &signal->waiters_list);
+
 		/*
 		 * As we do not allow WAIT to preempt inflight requests,
 		 * once we have executed a request, along with triggering

drivers/gpu/drm/i915/i915_utils.c

@@ -8,9 +8,8 @@
 #include "i915_drv.h"
 #include "i915_utils.h"
 
-#define FDO_BUG_URL "https://bugs.freedesktop.org/enter_bug.cgi?product=DRI"
+#define FDO_BUG_URL "https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs"
-#define FDO_BUG_MSG "Please file a bug at " FDO_BUG_URL " against DRM/Intel " \
+#define FDO_BUG_MSG "Please file a bug on drm/i915; see " FDO_BUG_URL " for details."
-		    "providing the dmesg log by booting with drm.debug=0xf"
 
 void
 __i915_printk(struct drm_i915_private *dev_priv, const char *level,