Merge tag 'drm-intel-fixes-2017-04-12' of git://anongit.freedesktop.org/git/drm-intel into drm-fixes

drm/i915 fixes for v4.11-rc7

one rcu related fix, and a few GVT fixes.

* tag 'drm-intel-fixes-2017-04-12' of git://anongit.freedesktop.org/git/drm-intel:
  drm/i915: Don't call synchronize_rcu_expedited under struct_mutex
  drm/i915: Suspend GuC prior to GPU Reset during GEM suspend
  drm/i915/gvt: set the correct default value of CTX STATUS PTR
  drm/i915/gvt: Fix firmware loading interface for GVT-g golden HW state
  drm/i915: Use a dummy timeline name for a signaled fence
  drm/i915: Ironlake do_idle_maps w/a may be called w/o struct_mutex
  drm/i915/gvt: remove the redundant info NULL check
  drm/i915/gvt: adjust mem size for low resolution type
  drm/i915: Avoid lock dropping between rescheduling
  drm/i915/gvt: exclude cfg space from failsafe mode
  drm/i915/gvt: Activate/de-activate vGPU in mdev ops.
  drm/i915/execlists: Wrap tail pointer after reset tweaking
  drm/i915/perf: remove user triggerable warn
  drm/i915/perf: destroy stream on sample_flags mismatch
  drm/i915: Align "unfenced" tiled access on gen2, early gen3

18 files changed, 138 insertions, 69 deletions

diff --git a/drivers/gpu/drm/i915/gvt/cfg_space.c b/drivers/gpu/drm/i915/gvt/cfg_space.c
index b7d7721e72fa..40af17ec6312 100644
--- a/drivers/gpu/drm/i915/gvt/cfg_space.c
+++ b/drivers/gpu/drm/i915/gvt/cfg_space.c
@@ -285,9 +285,6 @@ int intel_vgpu_emulate_cfg_write(struct intel_vgpu *vgpu, unsigned int offset,
 {
 	int ret;
 
-	if (vgpu->failsafe)
-		return 0;
-
 	if (WARN_ON(bytes > 4))
 		return -EINVAL;
 
diff --git a/drivers/gpu/drm/i915/gvt/execlist.c b/drivers/gpu/drm/i915/gvt/execlist.c
index f1f426a97aa9..d186c157f65f 100644
--- a/drivers/gpu/drm/i915/gvt/execlist.c
+++ b/drivers/gpu/drm/i915/gvt/execlist.c
@@ -775,7 +775,8 @@ static void init_vgpu_execlist(struct intel_vgpu *vgpu, int ring_id)
 			_EL_OFFSET_STATUS_PTR);
 
 	ctx_status_ptr.dw = vgpu_vreg(vgpu, ctx_status_ptr_reg);
-	ctx_status_ptr.read_ptr = ctx_status_ptr.write_ptr = 0x7;
+	ctx_status_ptr.read_ptr = 0;
+	ctx_status_ptr.write_ptr = 0x7;
 	vgpu_vreg(vgpu, ctx_status_ptr_reg) = ctx_status_ptr.dw;
 }
 
diff --git a/drivers/gpu/drm/i915/gvt/firmware.c b/drivers/gpu/drm/i915/gvt/firmware.c
index 933a7c211a1c..dce8d15f706f 100644
--- a/drivers/gpu/drm/i915/gvt/firmware.c
+++ b/drivers/gpu/drm/i915/gvt/firmware.c
@@ -75,11 +75,11 @@ static int expose_firmware_sysfs(struct intel_gvt *gvt)
 	struct gvt_firmware_header *h;
 	void *firmware;
 	void *p;
-	unsigned long size;
+	unsigned long size, crc32_start;
 	int i;
 	int ret;
 
-	size = sizeof(*h) + info->mmio_size + info->cfg_space_size - 1;
+	size = sizeof(*h) + info->mmio_size + info->cfg_space_size;
 	firmware = vzalloc(size);
 	if (!firmware)
 		return -ENOMEM;
@@ -112,6 +112,9 @@ static int expose_firmware_sysfs(struct intel_gvt *gvt)
 
 	memcpy(gvt->firmware.mmio, p, info->mmio_size);
 
+	crc32_start = offsetof(struct gvt_firmware_header, crc32) + 4;
+	h->crc32 = crc32_le(0, firmware + crc32_start, size - crc32_start);
+
 	firmware_attr.size = size;
 	firmware_attr.private = firmware;
 
@@ -234,7 +237,7 @@ int intel_gvt_load_firmware(struct intel_gvt *gvt)
 
 	firmware->mmio = mem;
 
-	sprintf(path, "%s/vid_0x%04x_did_0x%04x_rid_0x%04x.golden_hw_state",
+	sprintf(path, "%s/vid_0x%04x_did_0x%04x_rid_0x%02x.golden_hw_state",
 		 GVT_FIRMWARE_PATH, pdev->vendor, pdev->device,
 		 pdev->revision);
 
diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
index 3b9d59e457ba..ef3baa0c4754 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.c
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -52,6 +52,8 @@ static const struct intel_gvt_ops intel_gvt_ops = {
 	.vgpu_create = intel_gvt_create_vgpu,
 	.vgpu_destroy = intel_gvt_destroy_vgpu,
 	.vgpu_reset = intel_gvt_reset_vgpu,
+	.vgpu_activate = intel_gvt_activate_vgpu,
+	.vgpu_deactivate = intel_gvt_deactivate_vgpu,
 };
 
 /**
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index 6dfc48b63b71..becae2fa3b29 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -382,7 +382,8 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu);
 void intel_gvt_reset_vgpu_locked(struct intel_vgpu *vgpu, bool dmlr,
 				 unsigned int engine_mask);
 void intel_gvt_reset_vgpu(struct intel_vgpu *vgpu);
-
+void intel_gvt_activate_vgpu(struct intel_vgpu *vgpu);
+void intel_gvt_deactivate_vgpu(struct intel_vgpu *vgpu);
 
 /* validating GM functions */
 #define vgpu_gmadr_is_aperture(vgpu, gmadr) \
@@ -449,6 +450,8 @@ struct intel_gvt_ops {
 				struct intel_vgpu_type *);
 	void (*vgpu_destroy)(struct intel_vgpu *);
 	void (*vgpu_reset)(struct intel_vgpu *);
+	void (*vgpu_activate)(struct intel_vgpu *);
+	void (*vgpu_deactivate)(struct intel_vgpu *);
 };
 
 
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index d641214578a7..e466259034e2 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -544,6 +544,8 @@ static int intel_vgpu_open(struct mdev_device *mdev)
 	if (ret)
 		goto undo_group;
 
+	intel_gvt_ops->vgpu_activate(vgpu);
+
 	atomic_set(&vgpu->vdev.released, 0);
 	return ret;
 
@@ -569,6 +571,8 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 	if (atomic_cmpxchg(&vgpu->vdev.released, 0, 1))
 		return;
 
+	intel_gvt_ops->vgpu_deactivate(vgpu);
+
 	ret = vfio_unregister_notifier(mdev_dev(vgpu->vdev.mdev), VFIO_IOMMU_NOTIFY,
 					&vgpu->vdev.iommu_notifier);
 	WARN(ret, "vfio_unregister_notifier for iommu failed: %d\n", ret);
@@ -1340,13 +1344,6 @@ static int kvmgt_guest_init(struct mdev_device *mdev)
 
 static bool kvmgt_guest_exit(struct kvmgt_guest_info *info)
 {
-	struct intel_vgpu *vgpu = info->vgpu;
-
-	if (!info) {
-		gvt_vgpu_err("kvmgt_guest_info invalid\n");
-		return false;
-	}
-
 	kvm_page_track_unregister_notifier(info->kvm, &info->track_node);
 	kvm_put_kvm(info->kvm);
 	kvmgt_protect_table_destroy(info);
diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
index 41cfa5ccae84..649ef280cc9a 100644
--- a/drivers/gpu/drm/i915/gvt/vgpu.c
+++ b/drivers/gpu/drm/i915/gvt/vgpu.c
@@ -72,7 +72,7 @@ static struct {
 	char *name;
 } vgpu_types[] = {
 /* Fixed vGPU type table */
-	{ MB_TO_BYTES(64), MB_TO_BYTES(512), 4, GVT_EDID_1024_768, "8" },
+	{ MB_TO_BYTES(64), MB_TO_BYTES(384), 4, GVT_EDID_1024_768, "8" },
 	{ MB_TO_BYTES(128), MB_TO_BYTES(512), 4, GVT_EDID_1920_1200, "4" },
 	{ MB_TO_BYTES(256), MB_TO_BYTES(1024), 4, GVT_EDID_1920_1200, "2" },
 	{ MB_TO_BYTES(512), MB_TO_BYTES(2048), 4, GVT_EDID_1920_1200, "1" },
@@ -179,20 +179,34 @@ static void intel_gvt_update_vgpu_types(struct intel_gvt *gvt)
 }
 
 /**
- * intel_gvt_destroy_vgpu - destroy a virtual GPU
+ * intel_gvt_active_vgpu - activate a virtual GPU
  * @vgpu: virtual GPU
  *
- * This function is called when user wants to destroy a virtual GPU.
+ * This function is called when user wants to activate a virtual GPU.
  *
  */
-void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)
+void intel_gvt_activate_vgpu(struct intel_vgpu *vgpu)
+{
+	mutex_lock(&vgpu->gvt->lock);
+	vgpu->active = true;
+	mutex_unlock(&vgpu->gvt->lock);
+}
+
+/**
+ * intel_gvt_deactive_vgpu - deactivate a virtual GPU
+ * @vgpu: virtual GPU
+ *
+ * This function is called when user wants to deactivate a virtual GPU.
+ * All virtual GPU runtime information will be destroyed.
+ *
+ */
+void intel_gvt_deactivate_vgpu(struct intel_vgpu *vgpu)
 {
 	struct intel_gvt *gvt = vgpu->gvt;
 
 	mutex_lock(&gvt->lock);
 
 	vgpu->active = false;
-	idr_remove(&gvt->vgpu_idr, vgpu->id);
 
 	if (atomic_read(&vgpu->running_workload_num)) {
 		mutex_unlock(&gvt->lock);
@@ -201,6 +215,26 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)
 	}
 
 	intel_vgpu_stop_schedule(vgpu);
+
+	mutex_unlock(&gvt->lock);
+}
+
+/**
+ * intel_gvt_destroy_vgpu - destroy a virtual GPU
+ * @vgpu: virtual GPU
+ *
+ * This function is called when user wants to destroy a virtual GPU.
+ *
+ */
+void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)
+{
+	struct intel_gvt *gvt = vgpu->gvt;
+
+	mutex_lock(&gvt->lock);
+
+	WARN(vgpu->active, "vGPU is still active!\n");
+
+	idr_remove(&gvt->vgpu_idr, vgpu->id);
 	intel_vgpu_clean_sched_policy(vgpu);
 	intel_vgpu_clean_gvt_context(vgpu);
 	intel_vgpu_clean_execlist(vgpu);
@@ -277,7 +311,6 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
 	if (ret)
 		goto out_clean_shadow_ctx;
 
-	vgpu->active = true;
 	mutex_unlock(&gvt->lock);
 
 	return vgpu;
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 1c75402a59c1..5c089b3c2a7e 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1434,8 +1434,6 @@ static int i915_drm_suspend(struct drm_device *dev)
 		goto out;
 	}
 
-	intel_guc_suspend(dev_priv);
-
 	intel_display_suspend(dev);
 
 	intel_dp_mst_suspend(dev);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1e53c31b6826..46fcd8b7080a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -806,6 +806,7 @@ struct intel_csr {
 	func(has_resource_streamer); \
 	func(has_runtime_pm); \
 	func(has_snoop); \
+	func(unfenced_needs_alignment); \
 	func(cursor_needs_physical); \
 	func(hws_needs_physical); \
 	func(overlay_needs_physical); \
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 67b1fc5a0331..fe531f904062 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4348,6 +4348,8 @@ int i915_gem_suspend(struct drm_i915_private *dev_priv)
 	i915_gem_context_lost(dev_priv);
 	mutex_unlock(&dev->struct_mutex);
 
+	intel_guc_suspend(dev_priv);
+
 	cancel_delayed_work_sync(&dev_priv->gpu_error.hangcheck_work);
 	cancel_delayed_work_sync(&dev_priv->gt.retire_work);
 
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 30e0675fd7da..15a15d00a6bf 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -888,6 +888,7 @@ i915_gem_execbuffer_reserve(struct intel_engine_cs *engine,
 	struct list_head ordered_vmas;
 	struct list_head pinned_vmas;
 	bool has_fenced_gpu_access = INTEL_GEN(engine->i915) < 4;
+	bool needs_unfenced_map = INTEL_INFO(engine->i915)->unfenced_needs_alignment;
 	int retry;
 
 	vm = list_first_entry(vmas, struct i915_vma, exec_list)->vm;
@@ -908,7 +909,8 @@ i915_gem_execbuffer_reserve(struct intel_engine_cs *engine,
 		if (!has_fenced_gpu_access)
 			entry->flags &= ~EXEC_OBJECT_NEEDS_FENCE;
 		need_fence =
-			entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
+			(entry->flags & EXEC_OBJECT_NEEDS_FENCE ||
+			 needs_unfenced_map) &&
 			i915_gem_object_is_tiled(obj);
 		need_mappable = need_fence || need_reloc_mappable(vma);
 
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 2801a4d56324..96e45a4d5441 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2704,7 +2704,7 @@ void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj,
 	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 
 	if (unlikely(ggtt->do_idle_maps)) {
-		if (i915_gem_wait_for_idle(dev_priv, I915_WAIT_LOCKED)) {
+		if (i915_gem_wait_for_idle(dev_priv, 0)) {
 			DRM_ERROR("Failed to wait for idle; VT'd may hang.\n");
 			/* Wait a bit, in hopes it avoids the hang */
 			udelay(10);
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index e7c3c0318ff6..da70bfe97ec5 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -37,6 +37,17 @@ static const char *i915_fence_get_driver_name(struct dma_fence *fence)
 
 static const char *i915_fence_get_timeline_name(struct dma_fence *fence)
 {
+	/* The timeline struct (as part of the ppgtt underneath a context)
+	 * may be freed when the request is no longer in use by the GPU.
+	 * We could extend the life of a context to beyond that of all
+	 * fences, possibly keeping the hw resource around indefinitely,
+	 * or we just give them a false name. Since
+	 * dma_fence_ops.get_timeline_name is a debug feature, the occasional
+	 * lie seems justifiable.
+	 */
+	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+		return "signaled";
+
 	return to_request(fence)->timeline->common->name;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index d5d2b4c6ed38..70b3832a79dd 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -53,6 +53,17 @@ static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
 	BUG();
 }
 
+static void i915_gem_shrinker_unlock(struct drm_device *dev, bool unlock)
+{
+	if (!unlock)
+		return;
+
+	mutex_unlock(&dev->struct_mutex);
+
+	/* expedite the RCU grace period to free some request slabs */
+	synchronize_rcu_expedited();
+}
+
 static bool any_vma_pinned(struct drm_i915_gem_object *obj)
 {
 	struct i915_vma *vma;
@@ -232,11 +243,8 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
 		intel_runtime_pm_put(dev_priv);
 
 	i915_gem_retire_requests(dev_priv);
-	if (unlock)
-		mutex_unlock(&dev_priv->drm.struct_mutex);
 
-	/* expedite the RCU grace period to free some request slabs */
-	synchronize_rcu_expedited();
+	i915_gem_shrinker_unlock(&dev_priv->drm, unlock);
 
 	return count;
 }
@@ -293,8 +301,7 @@ i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 			count += obj->base.size >> PAGE_SHIFT;
 	}
 
-	if (unlock)
-		mutex_unlock(&dev->struct_mutex);
+	i915_gem_shrinker_unlock(dev, unlock);
 
 	return count;
 }
@@ -321,8 +328,8 @@ i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 					 sc->nr_to_scan - freed,
 					 I915_SHRINK_BOUND |
 					 I915_SHRINK_UNBOUND);
-	if (unlock)
-		mutex_unlock(&dev->struct_mutex);
+
+	i915_gem_shrinker_unlock(dev, unlock);
 
 	return freed;
 }
@@ -364,8 +371,7 @@ i915_gem_shrinker_unlock_uninterruptible(struct drm_i915_private *dev_priv,
 					 struct shrinker_lock_uninterruptible *slu)
 {
 	dev_priv->mm.interruptible = slu->was_interruptible;
-	if (slu->unlock)
-		mutex_unlock(&dev_priv->drm.struct_mutex);
+	i915_gem_shrinker_unlock(&dev_priv->drm, slu->unlock);
 }
 
 static int
diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index ecb487b5356f..9bbbd4e83e3c 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -60,6 +60,7 @@
 	.has_overlay = 1, .overlay_needs_physical = 1, \
 	.has_gmch_display = 1, \
 	.hws_needs_physical = 1, \
+	.unfenced_needs_alignment = 1, \
 	.ring_mask = RENDER_RING, \
 	GEN_DEFAULT_PIPEOFFSETS, \
 	CURSOR_OFFSETS
@@ -101,6 +102,7 @@ static const struct intel_device_info intel_i915g_info = {
 	.platform = INTEL_I915G, .cursor_needs_physical = 1,
 	.has_overlay = 1, .overlay_needs_physical = 1,
 	.hws_needs_physical = 1,
+	.unfenced_needs_alignment = 1,
 };
 
 static const struct intel_device_info intel_i915gm_info = {
@@ -112,6 +114,7 @@ static const struct intel_device_info intel_i915gm_info = {
 	.supports_tv = 1,
 	.has_fbc = 1,
 	.hws_needs_physical = 1,
+	.unfenced_needs_alignment = 1,
 };
 
 static const struct intel_device_info intel_i945g_info = {
@@ -120,6 +123,7 @@ static const struct intel_device_info intel_i945g_info = {
 	.has_hotplug = 1, .cursor_needs_physical = 1,
 	.has_overlay = 1, .overlay_needs_physical = 1,
 	.hws_needs_physical = 1,
+	.unfenced_needs_alignment = 1,
 };
 
 static const struct intel_device_info intel_i945gm_info = {
@@ -130,6 +134,7 @@ static const struct intel_device_info intel_i945gm_info = {
 	.supports_tv = 1,
 	.has_fbc = 1,
 	.hws_needs_physical = 1,
+	.unfenced_needs_alignment = 1,
 };
 
 static const struct intel_device_info intel_g33_info = {
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index a1b7eec58be2..70964ca9251e 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -1705,7 +1705,7 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
 	 */
 	if (WARN_ON(stream->sample_flags != props->sample_flags)) {
 		ret = -ENODEV;
-		goto err_alloc;
+		goto err_flags;
 	}
 
 	list_add(&stream->link, &dev_priv->perf.streams);
@@ -1728,6 +1728,7 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
 
 err_open:
 	list_del(&stream->link);
+err_flags:
 	if (stream->ops->destroy)
 		stream->ops->destroy(stream);
 err_alloc:
@@ -1793,6 +1794,11 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv,
 		if (ret)
 			return ret;
 
+		if (id == 0 || id >= DRM_I915_PERF_PROP_MAX) {
+			DRM_DEBUG("Unknown i915 perf property ID\n");
+			return -EINVAL;
+		}
+
 		switch ((enum drm_i915_perf_property_id)id) {
 		case DRM_I915_PERF_PROP_CTX_HANDLE:
 			props->single_context = 1;
@@ -1862,9 +1868,8 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv,
 			props->oa_periodic = true;
 			props->oa_period_exponent = value;
 			break;
-		default:
+		case DRM_I915_PERF_PROP_MAX:
 			MISSING_CASE(id);
-			DRM_DEBUG("Unknown i915 perf property ID\n");
 			return -EINVAL;
 		}
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 471af3b480ad..47517a02f0a4 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -670,15 +670,14 @@ static void execlists_submit_request(struct drm_i915_gem_request *request)
 static struct intel_engine_cs *
 pt_lock_engine(struct i915_priotree *pt, struct intel_engine_cs *locked)
 {
-	struct intel_engine_cs *engine;
+	struct intel_engine_cs *engine =
+		container_of(pt, struct drm_i915_gem_request, priotree)->engine;
+
+	GEM_BUG_ON(!locked);
 
-	engine = container_of(pt,
-			      struct drm_i915_gem_request,
-			      priotree)->engine;
 	if (engine != locked) {
-		if (locked)
-			spin_unlock_irq(&locked->timeline->lock);
-		spin_lock_irq(&engine->timeline->lock);
+		spin_unlock(&locked->timeline->lock);
+		spin_lock(&engine->timeline->lock);
 	}
 
 	return engine;
@@ -686,7 +685,7 @@ pt_lock_engine(struct i915_priotree *pt, struct intel_engine_cs *locked)
 
 static void execlists_schedule(struct drm_i915_gem_request *request, int prio)
 {
-	struct intel_engine_cs *engine = NULL;
+	struct intel_engine_cs *engine;
 	struct i915_dependency *dep, *p;
 	struct i915_dependency stack;
 	LIST_HEAD(dfs);
@@ -720,26 +719,23 @@ static void execlists_schedule(struct drm_i915_gem_request *request, int prio)
 	list_for_each_entry_safe(dep, p, &dfs, dfs_link) {
 		struct i915_priotree *pt = dep->signaler;
 
-		list_for_each_entry(p, &pt->signalers_list, signal_link)
+		/* Within an engine, there can be no cycle, but we may
+		 * refer to the same dependency chain multiple times
+		 * (redundant dependencies are not eliminated) and across
+		 * engines.
+		 */
+		list_for_each_entry(p, &pt->signalers_list, signal_link) {
+			GEM_BUG_ON(p->signaler->priority < pt->priority);
 			if (prio > READ_ONCE(p->signaler->priority))
 				list_move_tail(&p->dfs_link, &dfs);
+		}
 
 		list_safe_reset_next(dep, p, dfs_link);
-		if (!RB_EMPTY_NODE(&pt->node))
-			continue;
-
-		engine = pt_lock_engine(pt, engine);
-
-		/* If it is not already in the rbtree, we can update the
-		 * priority inplace and skip over it (and its dependencies)
-		 * if it is referenced *again* as we descend the dfs.
-		 */
-		if (prio > pt->priority && RB_EMPTY_NODE(&pt->node)) {
-			pt->priority = prio;
-			list_del_init(&dep->dfs_link);
-		}
 	}
 
+	engine = request->engine;
+	spin_lock_irq(&engine->timeline->lock);
+
 	/* Fifo and depth-first replacement ensure our deps execute before us */
 	list_for_each_entry_safe_reverse(dep, p, &dfs, dfs_link) {
 		struct i915_priotree *pt = dep->signaler;
@@ -751,16 +747,15 @@ static void execlists_schedule(struct drm_i915_gem_request *request, int prio)
 		if (prio <= pt->priority)
 			continue;
 
-		GEM_BUG_ON(RB_EMPTY_NODE(&pt->node));
-
 		pt->priority = prio;
-		rb_erase(&pt->node, &engine->execlist_queue);
-		if (insert_request(pt, &engine->execlist_queue))
-			engine->execlist_first = &pt->node;
+		if (!RB_EMPTY_NODE(&pt->node)) {
+			rb_erase(&pt->node, &engine->execlist_queue);
+			if (insert_request(pt, &engine->execlist_queue))
+				engine->execlist_first = &pt->node;
+		}
 	}
 
-	if (engine)
-		spin_unlock_irq(&engine->timeline->lock);
+	spin_unlock_irq(&engine->timeline->lock);
 
 	/* XXX Do we need to preempt to make room for us and our deps? */
 }
@@ -1440,7 +1435,9 @@ static void reset_common_ring(struct intel_engine_cs *engine,
 	GEM_BUG_ON(request->ctx != port[0].request->ctx);
 
 	/* Reset WaIdleLiteRestore:bdw,skl as well */
-	request->tail = request->wa_tail - WA_TAIL_DWORDS * sizeof(u32);
+	request->tail =
+		intel_ring_wrap(request->ring,
+				request->wa_tail - WA_TAIL_DWORDS*sizeof(u32));
 }
 
 static int intel_logical_ring_emit_pdps(struct drm_i915_gem_request *req)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 13dccb18cd43..8cb2078c5bfc 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -521,11 +521,17 @@ static inline void intel_ring_advance(struct intel_ring *ring)
 	 */
 }
 
+static inline u32
+intel_ring_wrap(const struct intel_ring *ring, u32 pos)
+{
+	return pos & (ring->size - 1);
+}
+
 static inline u32 intel_ring_offset(struct intel_ring *ring, void *addr)
 {
 	/* Don't write ring->size (equivalent to 0) as that hangs some GPUs. */
 	u32 offset = addr - ring->vaddr;
-	return offset & (ring->size - 1);
+	return intel_ring_wrap(ring, offset);
 }
 
 int __intel_ring_space(int head, int tail, int size);