[PATCH v4 0/4] RCAR-DU, VSP1: Prevent pre-emptive frame flips on VSP1-DRM pipelines

[PATCH v4 0/4] RCAR-DU, VSP1: Prevent pre-emptive frame flips on VSP1-DRM pipelines

[Kieran Bingham]

The RCAR-DU utilises a running VSPD pipeline to perform processing for the
display pipeline. This presents the opportunity for some race conditions to
affect the quality of the display output.

To prevent reporting page flips early, we must track this timing through the
VSP1, and only allow the rcar-du object to report the page-flip completion
event after the VSP1 has processed.

This series ensures that tearing and flicker is prevented, without introducing
any (substantial) performance impact.

These patches have been tested by introducing artificial delays in the commit
code paths and verifying that no visual tearing or flickering occurs.

Extensive testing around the race window has been performed by dynamically
adapting the artificial delay between 15, and 17 seconds in 100uS increments
for periods of 5 seconds on each delay test. These tests have successfully run
for 3 hours.

Manual start/stop testing has also been performed.

Mauro: As this patchset covers two subsystems, and the DRM/DU side is dependant
upon the media/VSP side, If you are happy with these patches, Would it be
possible to get acks from you for integration through the DRM tree please?

Regards

Kieran

Kieran Bingham (3):
  v4l: vsp1: Postpone frame end handling in event of display list race
  v4l: vsp1: Extend VSP1 module API to allow DRM callbacks
  drm: rcar-du: Register a completion callback with VSP1

Laurent Pinchart (1):
  drm: rcar-du: Arm the page flip event after queuing the page flip

 drivers/gpu/drm/rcar-du/rcar_du_crtc.c  | 30 ++++++++++++++------------
 drivers/gpu/drm/rcar-du/rcar_du_crtc.h  |  1 +-
 drivers/gpu/drm/rcar-du/rcar_du_vsp.c   |  9 ++++++++-
 drivers/media/platform/vsp1/vsp1_dl.c   | 19 ++++++++++++++--
 drivers/media/platform/vsp1/vsp1_dl.h   |  2 +-
 drivers/media/platform/vsp1/vsp1_drm.c  | 17 +++++++++++++++-
 drivers/media/platform/vsp1/vsp1_drm.h  | 11 ++++++++++-
 drivers/media/platform/vsp1/vsp1_pipe.c | 13 ++++++++++-
 include/media/vsp1.h                    |  7 ++++++-
 9 files changed, 92 insertions(+), 17 deletions(-)

base-commit: 4df0f635a142c7498d20de9356851fb989c7f653
-- 
git-series 0.9.1

[PATCH v4 1/4] drm: rcar-du: Arm the page flip event after queuing the page flip

[Kieran Bingham]

From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

The page flip event is armed in the atomic begin handler, creating a
race condition with the frame end interrupt that could send the event
before the atomic operation actually completes. To avoid that, arm the
event in the atomic flush handler after queuing the page flip.

This change doesn't fully close the race window, as the frame end
interrupt could be generated before the page flip is committed to
hardware but only handled after the event is armed. However, the race
window is now much smaller.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 4ed6f2340af0..5f0664bcd12d 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -581,17 +581,6 @@ static void rcar_du_crtc_atomic_begin(struct drm_crtc *crtc,
 				      struct drm_crtc_state *old_crtc_state)
 {
 	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
-	struct drm_device *dev = rcrtc->crtc.dev;
-	unsigned long flags;
-
-	if (crtc->state->event) {
-		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
-
-		spin_lock_irqsave(&dev->event_lock, flags);
-		rcrtc->event = crtc->state->event;
-		crtc->state->event = NULL;
-		spin_unlock_irqrestore(&dev->event_lock, flags);
-	}
 
 	if (rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
 		rcar_du_vsp_atomic_begin(rcrtc);
@@ -601,9 +590,20 @@ static void rcar_du_crtc_atomic_flush(struct drm_crtc *crtc,
 				      struct drm_crtc_state *old_crtc_state)
 {
 	struct rcar_du_crtc *rcrtc = to_rcar_crtc(crtc);
+	struct drm_device *dev = rcrtc->crtc.dev;
+	unsigned long flags;
 
 	rcar_du_crtc_update_planes(rcrtc);
 
+	if (crtc->state->event) {
+		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
+
+		spin_lock_irqsave(&dev->event_lock, flags);
+		rcrtc->event = crtc->state->event;
+		crtc->state->event = NULL;
+		spin_unlock_irqrestore(&dev->event_lock, flags);
+	}
+
 	if (rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
 		rcar_du_vsp_atomic_flush(rcrtc);
 }
-- 
git-series 0.9.1

[PATCH v4 2/4] v4l: vsp1: Postpone frame end handling in event of display list race

[Kieran Bingham]

If we try to commit the display list while an update is pending, we have
missed our opportunity. The display list manager will hold the commit
until the next interrupt.

In this event, we skip the pipeline completion callback handler so that
the pipeline will not mistakenly report frame completion to the user.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/media/platform/vsp1/vsp1_dl.c   | 19 +++++++++++++++++--
 drivers/media/platform/vsp1/vsp1_dl.h   |  2 +-
 drivers/media/platform/vsp1/vsp1_pipe.c | 13 ++++++++++++-
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/vsp1/vsp1_dl.c b/drivers/media/platform/vsp1/vsp1_dl.c
index 7d8f37772b56..85fe2b4ae310 100644
--- a/drivers/media/platform/vsp1/vsp1_dl.c
+++ b/drivers/media/platform/vsp1/vsp1_dl.c
@@ -561,9 +561,19 @@ void vsp1_dlm_irq_display_start(struct vsp1_dl_manager *dlm)
 	spin_unlock(&dlm->lock);
 }
 
-void vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm)
+/**
+ * vsp1_dlm_irq_frame_end - Display list handler for the frame end interrupt
+ * @dlm: the display list manager
+ *
+ * Return true if the previous display list has completed at frame end, or false
+ * if it has been delayed by one frame because the display list commit raced
+ * with the frame end interrupt. The function always returns true in header mode
+ * as display list processing is then not continuous and races never occur.
+ */
+bool vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm)
 {
 	struct vsp1_device *vsp1 = dlm->vsp1;
+	bool completed = false;
 
 	spin_lock(&dlm->lock);
 
@@ -575,8 +585,10 @@ void vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm)
 	 * perform any operation as there can't be any new display list queued
 	 * in that case.
 	 */
-	if (dlm->mode == VSP1_DL_MODE_HEADER)
+	if (dlm->mode == VSP1_DL_MODE_HEADER) {
+		completed = true;
 		goto done;
+	}
 
 	/*
 	 * The UPD bit set indicates that the commit operation raced with the
@@ -594,6 +606,7 @@ void vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm)
 	if (dlm->queued) {
 		dlm->active = dlm->queued;
 		dlm->queued = NULL;
+		completed = true;
 	}
 
 	/*
@@ -614,6 +627,8 @@ void vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm)
 
 done:
 	spin_unlock(&dlm->lock);
+
+	return completed;
 }
 
 /* Hardware Setup */
diff --git a/drivers/media/platform/vsp1/vsp1_dl.h b/drivers/media/platform/vsp1/vsp1_dl.h
index 7131aa3c5978..6ec1380a10af 100644
--- a/drivers/media/platform/vsp1/vsp1_dl.h
+++ b/drivers/media/platform/vsp1/vsp1_dl.h
@@ -28,7 +28,7 @@ struct vsp1_dl_manager *vsp1_dlm_create(struct vsp1_device *vsp1,
 void vsp1_dlm_destroy(struct vsp1_dl_manager *dlm);
 void vsp1_dlm_reset(struct vsp1_dl_manager *dlm);
 void vsp1_dlm_irq_display_start(struct vsp1_dl_manager *dlm);
-void vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm);
+bool vsp1_dlm_irq_frame_end(struct vsp1_dl_manager *dlm);
 
 struct vsp1_dl_list *vsp1_dl_list_get(struct vsp1_dl_manager *dlm);
 void vsp1_dl_list_put(struct vsp1_dl_list *dl);
diff --git a/drivers/media/platform/vsp1/vsp1_pipe.c b/drivers/media/platform/vsp1/vsp1_pipe.c
index edebf3fa926f..e817623b84e0 100644
--- a/drivers/media/platform/vsp1/vsp1_pipe.c
+++ b/drivers/media/platform/vsp1/vsp1_pipe.c
@@ -330,10 +330,21 @@ bool vsp1_pipeline_ready(struct vsp1_pipeline *pipe)
 
 void vsp1_pipeline_frame_end(struct vsp1_pipeline *pipe)
 {
+	bool completed;
+
 	if (pipe == NULL)
 		return;
 
-	vsp1_dlm_irq_frame_end(pipe->output->dlm);
+	completed = vsp1_dlm_irq_frame_end(pipe->output->dlm);
+	if (!completed) {
+		/*
+		 * If the DL commit raced with the frame end interrupt, the
+		 * commit ends up being postponed by one frame. Return
+		 * immediately without calling the pipeline's frame end handler
+		 * or incrementing the sequence number.
+		 */
+		return;
+	}
 
 	if (pipe->hgo)
 		vsp1_hgo_frame_end(pipe->hgo);
-- 
git-series 0.9.1

[PATCH v4 3/4] v4l: vsp1: Extend VSP1 module API to allow DRM callbacks

[Kieran Bingham]

To be able to perform page flips in DRM without flicker we need to be
able to notify the rcar-du module when the VSP has completed its
processing.

We must not have bidirectional dependencies on the two components to
maintain support for loadable modules, thus we extend the API to allow
a callback to be registered within the VSP DRM interface.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/media/platform/vsp1/vsp1_drm.c | 17 +++++++++++++++++
 drivers/media/platform/vsp1/vsp1_drm.h | 11 +++++++++++
 include/media/vsp1.h                   |  7 +++++++
 3 files changed, 35 insertions(+)

diff --git a/drivers/media/platform/vsp1/vsp1_drm.c b/drivers/media/platform/vsp1/vsp1_drm.c
index 9d235e830f5a..84d0418660bf 100644
--- a/drivers/media/platform/vsp1/vsp1_drm.c
+++ b/drivers/media/platform/vsp1/vsp1_drm.c
@@ -36,6 +36,14 @@ void vsp1_drm_display_start(struct vsp1_device *vsp1)
 	vsp1_dlm_irq_display_start(vsp1->drm->pipe.output->dlm);
 }
 
+static void vsp1_du_pipeline_frame_end(struct vsp1_pipeline *pipe)
+{
+	struct vsp1_drm *drm = to_vsp1_drm(pipe);
+
+	if (drm->du_complete)
+		drm->du_complete(drm->du_private);
+}
+
 /* -----------------------------------------------------------------------------
  * DU Driver API
  */
@@ -95,6 +103,7 @@ int vsp1_du_setup_lif(struct device *dev, const struct vsp1_du_lif_config *cfg)
 		}
 
 		pipe->num_inputs = 0;
+		vsp1->drm->du_complete = NULL;
 
 		vsp1_dlm_reset(pipe->output->dlm);
 		vsp1_device_put(vsp1);
@@ -199,6 +208,13 @@ int vsp1_du_setup_lif(struct device *dev, const struct vsp1_du_lif_config *cfg)
 	if (ret < 0)
 		return ret;
 
+	/*
+	 * Register a callback to allow us to notify the DRM driver of frame
+	 * completion events.
+	 */
+	vsp1->drm->du_complete = cfg->callback;
+	vsp1->drm->du_private = cfg->callback_data;
+
 	ret = media_pipeline_start(&pipe->output->entity.subdev.entity,
 					  &pipe->pipe);
 	if (ret < 0) {
@@ -603,6 +619,7 @@ int vsp1_drm_init(struct vsp1_device *vsp1)
 	pipe->lif = &vsp1->lif->entity;
 	pipe->output = vsp1->wpf[0];
 	pipe->output->pipe = pipe;
+	pipe->frame_end = vsp1_du_pipeline_frame_end;
 
 	return 0;
 }
diff --git a/drivers/media/platform/vsp1/vsp1_drm.h b/drivers/media/platform/vsp1/vsp1_drm.h
index c8d2f88fc483..e9f80727ff92 100644
--- a/drivers/media/platform/vsp1/vsp1_drm.h
+++ b/drivers/media/platform/vsp1/vsp1_drm.h
@@ -23,6 +23,8 @@
  * @num_inputs: number of active pipeline inputs at the beginning of an update
  * @inputs: source crop rectangle, destination compose rectangle and z-order
  *	position for every input
+ * @du_complete: frame completion callback for the DU driver (optional)
+ * @du_private: data to be passed to the du_complete callback
  */
 struct vsp1_drm {
 	struct vsp1_pipeline pipe;
@@ -33,8 +35,17 @@ struct vsp1_drm {
 		struct v4l2_rect compose;
 		unsigned int zpos;
 	} inputs[VSP1_MAX_RPF];
+
+	/* Frame synchronisation */
+	void (*du_complete)(void *);
+	void *du_private;
 };
 
+static inline struct vsp1_drm *to_vsp1_drm(struct vsp1_pipeline *pipe)
+{
+	return container_of(pipe, struct vsp1_drm, pipe);
+}
+
 int vsp1_drm_init(struct vsp1_device *vsp1);
 void vsp1_drm_cleanup(struct vsp1_device *vsp1);
 int vsp1_drm_create_links(struct vsp1_device *vsp1);
diff --git a/include/media/vsp1.h b/include/media/vsp1.h
index 38aac554dbba..c135c47b4641 100644
--- a/include/media/vsp1.h
+++ b/include/media/vsp1.h
@@ -24,10 +24,17 @@ int vsp1_du_init(struct device *dev);
  * struct vsp1_du_lif_config - VSP LIF configuration
  * @width: output frame width
  * @height: output frame height
+ * @callback: frame completion callback function (optional). When a callback
+ *	      is provided, the VSP driver guarantees that it will be called once
+ *	      and only once for each vsp1_du_atomic_flush() call.
+ * @callback_data: data to be passed to the frame completion callback
  */
 struct vsp1_du_lif_config {
 	unsigned int width;
 	unsigned int height;
+
+	void (*callback)(void *);
+	void *callback_data;
 };
 
 int vsp1_du_setup_lif(struct device *dev, const struct vsp1_du_lif_config *cfg);
-- 
git-series 0.9.1

[PATCH v4 4/4] drm: rcar-du: Register a completion callback with VSP1

[Kieran Bingham]

Currently we process page flip events on every display interrupt,
however this does not take into consideration the processing time needed
by the VSP1 utilised in the pipeline.

Register a callback with the VSP driver to obtain completion events, and
track them so that we only perform page flips when the full display
pipeline has completed for the frame.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c |  8 ++++++--
 drivers/gpu/drm/rcar-du/rcar_du_crtc.h |  1 +
 drivers/gpu/drm/rcar-du/rcar_du_vsp.c  |  9 +++++++++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 5f0664bcd12d..345eff72f581 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -378,7 +378,7 @@ static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
  * Page Flip
  */
 
-static void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc)
+void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc)
 {
 	struct drm_pending_vblank_event *event;
 	struct drm_device *dev = rcrtc->crtc.dev;
@@ -650,6 +650,7 @@ static const struct drm_crtc_funcs crtc_funcs = {
 static irqreturn_t rcar_du_crtc_irq(int irq, void *arg)
 {
 	struct rcar_du_crtc *rcrtc = arg;
+	struct rcar_du_device *rcdu = rcrtc->group->dev;
 	irqreturn_t ret = IRQ_NONE;
 	u32 status;
 
@@ -658,7 +659,10 @@ static irqreturn_t rcar_du_crtc_irq(int irq, void *arg)
 
 	if (status & DSSR_FRM) {
 		drm_crtc_handle_vblank(&rcrtc->crtc);
-		rcar_du_crtc_finish_page_flip(rcrtc);
+
+		if (rcdu->info->gen < 3)
+			rcar_du_crtc_finish_page_flip(rcrtc);
+
 		ret = IRQ_HANDLED;
 	}
 
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
index 15871fae7445..b199ed5adf36 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
@@ -73,5 +73,6 @@ void rcar_du_crtc_resume(struct rcar_du_crtc *rcrtc);
 
 void rcar_du_crtc_route_output(struct drm_crtc *crtc,
 			       enum rcar_du_output output);
+void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc);
 
 #endif /* __RCAR_DU_CRTC_H__ */
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
index b0ff304ce3dc..c7bb96fbfab1 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
@@ -28,6 +28,13 @@
 #include "rcar_du_kms.h"
 #include "rcar_du_vsp.h"
 
+static void rcar_du_vsp_complete(void *private)
+{
+	struct rcar_du_crtc *crtc = private;
+
+	rcar_du_crtc_finish_page_flip(crtc);
+}
+
 void rcar_du_vsp_enable(struct rcar_du_crtc *crtc)
 {
 	const struct drm_display_mode *mode = &crtc->crtc.state->adjusted_mode;
@@ -35,6 +42,8 @@ void rcar_du_vsp_enable(struct rcar_du_crtc *crtc)
 	struct vsp1_du_lif_config cfg = {
 		.width = mode->hdisplay,
 		.height = mode->vdisplay,
+		.callback = rcar_du_vsp_complete,
+		.callback_data = crtc,
 	};
 	struct rcar_du_plane_state state = {
 		.state = {
-- 
git-series 0.9.1

Re: [PATCH v4 4/4] drm: rcar-du: Register a completion callback with VSP1

[Mauro Carvalho Chehab]

Em Fri,  5 May 2017 16:21:10 +0100
Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> escreveu:

> Currently we process page flip events on every display interrupt,
> however this does not take into consideration the processing time needed
> by the VSP1 utilised in the pipeline.
> 
> Register a callback with the VSP driver to obtain completion events, and
> track them so that we only perform page flips when the full display
> pipeline has completed for the frame.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

For all parts of this series that touch drivers/media:

Acked-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>


> ---
>  drivers/gpu/drm/rcar-du/rcar_du_crtc.c |  8 ++++++--
>  drivers/gpu/drm/rcar-du/rcar_du_crtc.h |  1 +
>  drivers/gpu/drm/rcar-du/rcar_du_vsp.c  |  9 +++++++++
>  3 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> index 5f0664bcd12d..345eff72f581 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> @@ -378,7 +378,7 @@ static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
>   * Page Flip
>   */
>  
> -static void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc)
> +void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc)
>  {
>  	struct drm_pending_vblank_event *event;
>  	struct drm_device *dev = rcrtc->crtc.dev;
> @@ -650,6 +650,7 @@ static const struct drm_crtc_funcs crtc_funcs = {
>  static irqreturn_t rcar_du_crtc_irq(int irq, void *arg)
>  {
>  	struct rcar_du_crtc *rcrtc = arg;
> +	struct rcar_du_device *rcdu = rcrtc->group->dev;
>  	irqreturn_t ret = IRQ_NONE;
>  	u32 status;
>  
> @@ -658,7 +659,10 @@ static irqreturn_t rcar_du_crtc_irq(int irq, void *arg)
>  
>  	if (status & DSSR_FRM) {
>  		drm_crtc_handle_vblank(&rcrtc->crtc);
> -		rcar_du_crtc_finish_page_flip(rcrtc);
> +
> +		if (rcdu->info->gen < 3)
> +			rcar_du_crtc_finish_page_flip(rcrtc);
> +
>  		ret = IRQ_HANDLED;
>  	}
>  
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
> index 15871fae7445..b199ed5adf36 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
> @@ -73,5 +73,6 @@ void rcar_du_crtc_resume(struct rcar_du_crtc *rcrtc);
>  
>  void rcar_du_crtc_route_output(struct drm_crtc *crtc,
>  			       enum rcar_du_output output);
> +void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc);
>  
>  #endif /* __RCAR_DU_CRTC_H__ */
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> index b0ff304ce3dc..c7bb96fbfab1 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> @@ -28,6 +28,13 @@
>  #include "rcar_du_kms.h"
>  #include "rcar_du_vsp.h"
>  
> +static void rcar_du_vsp_complete(void *private)
> +{
> +	struct rcar_du_crtc *crtc = private;
> +
> +	rcar_du_crtc_finish_page_flip(crtc);
> +}
> +
>  void rcar_du_vsp_enable(struct rcar_du_crtc *crtc)
>  {
>  	const struct drm_display_mode *mode = &crtc->crtc.state->adjusted_mode;
> @@ -35,6 +42,8 @@ void rcar_du_vsp_enable(struct rcar_du_crtc *crtc)
>  	struct vsp1_du_lif_config cfg = {
>  		.width = mode->hdisplay,
>  		.height = mode->vdisplay,
> +		.callback = rcar_du_vsp_complete,
> +		.callback_data = crtc,
>  	};
>  	struct rcar_du_plane_state state = {
>  		.state = {



Thanks,
Mauro