diff mbox

[v2,2/3] drm: rcar-du: Fix planes to CRTC assignment when using the VSP

Message ID 20170711222942.27735-3-laurent.pinchart+renesas@ideasonboard.com (mailing list archive)
State New, archived
Headers show

Commit Message

Laurent Pinchart July 11, 2017, 10:29 p.m. UTC
The DU can compose the output of a VSP with other planes on Gen2
hardware, and of two VSPs on Gen3 hardware. Neither of these features
are supported by the driver, and the current implementation always
assigns planes to CRTCs the same way.

Simplify the implementation by configuring plane assignment when setting
up DU groups, instead of recomputing it for every atomic plane update.
This allows skipping the wait for vertical blanking when stopping a
CRTC, as there's no need to reconfigure plane assignment at that point.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c  | 31 ++++++++++++++++---------------
 drivers/gpu/drm/rcar-du/rcar_du_group.c | 12 ++++++++++++
 drivers/gpu/drm/rcar-du/rcar_du_kms.c   | 28 +++++++++++++++++-----------
 drivers/gpu/drm/rcar-du/rcar_du_plane.c | 10 +---------
 drivers/gpu/drm/rcar-du/rcar_du_vsp.c   |  9 ---------
 5 files changed, 46 insertions(+), 44 deletions(-)

Comments

Kieran Bingham July 12, 2017, 10:30 a.m. UTC | #1
Hi Laurent,

Thanks for the patch

Only a minor nit on one comment, but aside from that,

On 11/07/17 23:29, Laurent Pinchart wrote:
> The DU can compose the output of a VSP with other planes on Gen2
> hardware, and of two VSPs on Gen3 hardware. Neither of these features
> are supported by the driver, and the current implementation always
> assigns planes to CRTCs the same way.
> 
> Simplify the implementation by configuring plane assignment when setting
> up DU groups, instead of recomputing it for every atomic plane update.
> This allows skipping the wait for vertical blanking when stopping a
> CRTC, as there's no need to reconfigure plane assignment at that point.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

> ---
>  drivers/gpu/drm/rcar-du/rcar_du_crtc.c  | 31 ++++++++++++++++---------------
>  drivers/gpu/drm/rcar-du/rcar_du_group.c | 12 ++++++++++++
>  drivers/gpu/drm/rcar-du/rcar_du_kms.c   | 28 +++++++++++++++++-----------
>  drivers/gpu/drm/rcar-du/rcar_du_plane.c | 10 +---------
>  drivers/gpu/drm/rcar-du/rcar_du_vsp.c   |  9 ---------
>  5 files changed, 46 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> index 17fd1cd5212c..413ab032afed 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> @@ -315,6 +315,10 @@ static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
>  	unsigned int i;
>  	u32 dspr = 0;
>  
> +	/* Plane assignment is fixed when using the VSP. */
> +	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE))
> +		return;
> +
>  	for (i = 0; i < rcrtc->group->num_planes; ++i) {
>  		struct rcar_du_plane *plane = &rcrtc->group->planes[i];
>  		unsigned int j;
> @@ -351,17 +355,6 @@ static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
>  		}
>  	}
>  
> -	/* If VSP+DU integration is enabled the plane assignment is fixed. */
> -	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
> -		if (rcdu->info->gen < 3) {
> -			dspr = (rcrtc->index % 2) + 1;
> -			hwplanes = 1 << (rcrtc->index % 2);
> -		} else {
> -			dspr = (rcrtc->index % 2) ? 3 : 1;
> -			hwplanes = 1 << ((rcrtc->index % 2) ? 2 : 0);
> -		}
> -	}
> -
>  	/*
>  	 * Update the planes to display timing and dot clock generator
>  	 * associations.
> @@ -462,8 +455,13 @@ static void rcar_du_crtc_setup(struct rcar_du_crtc *rcrtc)
>  	rcar_du_crtc_set_display_timing(rcrtc);
>  	rcar_du_group_set_routing(rcrtc->group);
>  
> -	/* Start with all planes disabled. */
> -	rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR, 0);
> +	/*
> +	 * Start with all planes disabled, except when using the VSP in which
> +	 * case the fixed plane assignment must not be modified.
> +	 */
> +	if (!rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
> +		rcar_du_group_write(rcrtc->group,
> +				    rcrtc->index % 2 ? DS2PR : DS1PR, 0);
>  
>  	/* Enable the VSP compositor. */
>  	if (rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
> @@ -505,8 +503,11 @@ static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc)
>  	 * are stopped in one operation as we now wait for one vblank per CRTC.
>  	 * Whether this can be improved needs to be researched.
>  	 */
> -	rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR, 0);
> -	drm_crtc_wait_one_vblank(crtc);
> +	if (!rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE)) {
> +		rcar_du_group_write(rcrtc->group,
> +				    rcrtc->index % 2 ? DS2PR : DS1PR, 0);
> +		drm_crtc_wait_one_vblank(crtc);
> +	}
>  
>  	/*
>  	 * Disable vertical blanking interrupt reporting. We first need to wait
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c b/drivers/gpu/drm/rcar-du/rcar_du_group.c
> index 00d5f470d377..d26b647207b8 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_group.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
> @@ -126,6 +126,18 @@ static void rcar_du_group_setup(struct rcar_du_group *rgrp)
>  	if (rcdu->info->gen >= 3)
>  		rcar_du_group_write(rgrp, DEFR10, DEFR10_CODE | DEFR10_DEFE10);
>  
> +	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
> +		/*
> +		 * The CRTCs can compose the output of a VSP with other planes
> +		 * on Gen2 hardware, and of two VSPs on Gen3 hardware. Neither
> +		 * of these features are supported by the driver, so we hardcode
> +		 * plane assignment to CRTCs when setting the group up to avoid
> +		 * the need to restart then group when setting planes up.

Minor nits in comment:

  /restart then group/restart the group/

I would also possibly swap the final 'planes up' as 'up planes' if you update
here anyway:

* so we hardcode plane assignment to CRTCs when setting the group up to avoid
* the need to restart the group when setting up planes.

Up to you of course :)


> +		 */
> +		rcar_du_group_write(rgrp, DS1PR, 1);
> +		rcar_du_group_write(rgrp, DS2PR, rcdu->info->gen >= 3 ? 3 : 2);

whew ... that DS2PR indexing change from g2 to g3 looks annoying ... I had to
write out the logic tables on paper to verify the change here from the previous
code.

> +	}
> +
>  	/*
>  	 * Use DS1PR and DS2PR to configure planes priorities and connects the
>  	 * superposition 0 to DU0 pins. DU1 pins will be configured dynamically.
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> index 0e4e839afc97..13186a5684f1 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> @@ -562,17 +562,23 @@ int rcar_du_modeset_init(struct rcar_du_device *rcdu)
>  		rgrp->index = i;
>  		rgrp->num_crtcs = min(rcdu->num_crtcs - 2 * i, 2U);
>  
> -		/*
> -		 * If we have more than one CRTCs in this group pre-associate
> -		 * the low-order planes with CRTC 0 and the high-order planes
> -		 * with CRTC 1 to minimize flicker occurring when the
> -		 * association is changed.
> -		 */
> -		rgrp->dptsr_planes = rgrp->num_crtcs > 1
> -				   ? (rcdu->info->gen >= 3 ? 0x04 : 0xf0)
> -				   : 0;
> -
> -		if (!rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
> +		if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
> +			/*
> +			 * When using the VSP plane assignment to CRTCs is
> +			 * fixed. The first VSP is connected to plane 1, and the
> +			 * second VSP to plane 2 on Gen2 hardware and to plane 3
> +			 * on Gen3 hardware.
> +			 */
> +			rgrp->dptsr_planes = rgrp->num_crtcs > 1
> +					   ? (rcdu->info->gen >= 3 ? 4 : 2)
> +					   : 0;
> +		} else {
> +			/*
> +			 * Pre-associate the planes with the CRTCs if we have
> +			 * more than one CRTC in this group to minimize flicker
> +			 * when plane association is changed.
> +			 */
> +			rgrp->dptsr_planes = rgrp->num_crtcs > 1 ? 0xf0 : 0x00;
>  			ret = rcar_du_planes_init(rgrp);
>  			if (ret < 0)
>  				return ret;
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_plane.c b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
> index b0040478a3db..787f036b18fb 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_plane.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
> @@ -548,17 +548,9 @@ void __rcar_du_plane_setup(struct rcar_du_group *rgrp,
>  		rcar_du_plane_setup_format(rgrp, (state->hwindex + 1) % 8,
>  					   state);
>  
> +	/* On Gen3 planes have no scanout data. */
>  	if (rcdu->info->gen < 3)
>  		rcar_du_plane_setup_scanout(rgrp, state);
> -
> -	if (state->source == RCAR_DU_PLANE_VSPD1) {
> -		unsigned int vspd1_sink = rgrp->index ? 2 : 0;
> -
> -		if (rcdu->vspd1_sink != vspd1_sink) {
> -			rcdu->vspd1_sink = vspd1_sink;
> -			rcar_du_set_dpad0_vsp1_routing(rcdu);
> -		}
> -	}
>  }
>  
>  static int rcar_du_plane_atomic_check(struct drm_plane *plane,
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> index e43b065e141a..dba150a20f3d 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> @@ -74,15 +74,6 @@ void rcar_du_vsp_enable(struct rcar_du_crtc *crtc)
>  
>  	__rcar_du_plane_setup(crtc->group, &state);
>  
> -	/*
> -	 * Ensure that the plane source configuration takes effect by requesting
> -	 * a restart of the group. See rcar_du_plane_atomic_update() for a more
> -	 * detailed explanation.
> -	 *
> -	 * TODO: Check whether this is still needed on Gen3.
> -	 */
> -	crtc->group->need_restart = true;
> -
>  	vsp1_du_setup_lif(crtc->vsp->vsp, crtc->vsp_pipe, &cfg);
>  }
>  
>
Laurent Pinchart July 12, 2017, 12:13 p.m. UTC | #2
Hi Kieran,

On Wednesday 12 Jul 2017 11:30:19 Kieran Bingham wrote:
> On 11/07/17 23:29, Laurent Pinchart wrote:
> > The DU can compose the output of a VSP with other planes on Gen2
> > hardware, and of two VSPs on Gen3 hardware. Neither of these features
> > are supported by the driver, and the current implementation always
> > assigns planes to CRTCs the same way.
> > 
> > Simplify the implementation by configuring plane assignment when setting
> > up DU groups, instead of recomputing it for every atomic plane update.
> > This allows skipping the wait for vertical blanking when stopping a
> > CRTC, as there's no need to reconfigure plane assignment at that point.
> > 
> > Signed-off-by: Laurent Pinchart
> > <laurent.pinchart+renesas@ideasonboard.com>
> 
> Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> 
> > ---
> > 
> >  drivers/gpu/drm/rcar-du/rcar_du_crtc.c  | 31 ++++++++++++++-------------
> >  drivers/gpu/drm/rcar-du/rcar_du_group.c | 12 ++++++++++++
> >  drivers/gpu/drm/rcar-du/rcar_du_kms.c   | 28 +++++++++++++++++-----------
> >  drivers/gpu/drm/rcar-du/rcar_du_plane.c | 10 +---------
> >  drivers/gpu/drm/rcar-du/rcar_du_vsp.c   |  9 ---------
> >  5 files changed, 46 insertions(+), 44 deletions(-)

[snip]

> > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c
> > b/drivers/gpu/drm/rcar-du/rcar_du_group.c index
> > 00d5f470d377..d26b647207b8 100644
> > --- a/drivers/gpu/drm/rcar-du/rcar_du_group.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
> > @@ -126,6 +126,18 @@ static void rcar_du_group_setup(struct rcar_du_group
> > *rgrp)> 
> >  	if (rcdu->info->gen >= 3)
> >  		rcar_du_group_write(rgrp, DEFR10, DEFR10_CODE | 
DEFR10_DEFE10);
> > 
> > +	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
> > +		/*
> > +		 * The CRTCs can compose the output of a VSP with other planes
> > +		 * on Gen2 hardware, and of two VSPs on Gen3 hardware. Neither
> > +		 * of these features are supported by the driver, so we 
hardcode
> > +		 * plane assignment to CRTCs when setting the group up to 
avoid
> > +		 * the need to restart then group when setting planes up.
> 
> Minor nits in comment:
> 
>   /restart then group/restart the group/
> 
> I would also possibly swap the final 'planes up' as 'up planes' if you
> update here anyway:
> 
> * so we hardcode plane assignment to CRTCs when setting the group up to
> avoid
> * the need to restart the group when setting up planes.
> 
> Up to you of course :)

Thanks, I've fixed both, and also replaced "setting the group up" with 
"setting up the group".

> > +		 */
> > +		rcar_du_group_write(rgrp, DS1PR, 1);
> > +		rcar_du_group_write(rgrp, DS2PR, rcdu->info->gen >= 3 ? 3 : 
2);
> 
> whew ... that DS2PR indexing change from g2 to g3 looks annoying ... I had
> to write out the logic tables on paper to verify the change here from the
> previous code.

That's also how I wrote the code :-)

> > +	}
> > +
> > 
> >  	/*
> >  	
> >  	 * Use DS1PR and DS2PR to configure planes priorities and connects the
> >  	 * superposition 0 to DU0 pins. DU1 pins will be configured 
dynamically.
diff mbox

Patch

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 17fd1cd5212c..413ab032afed 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -315,6 +315,10 @@  static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
 	unsigned int i;
 	u32 dspr = 0;
 
+	/* Plane assignment is fixed when using the VSP. */
+	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE))
+		return;
+
 	for (i = 0; i < rcrtc->group->num_planes; ++i) {
 		struct rcar_du_plane *plane = &rcrtc->group->planes[i];
 		unsigned int j;
@@ -351,17 +355,6 @@  static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
 		}
 	}
 
-	/* If VSP+DU integration is enabled the plane assignment is fixed. */
-	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
-		if (rcdu->info->gen < 3) {
-			dspr = (rcrtc->index % 2) + 1;
-			hwplanes = 1 << (rcrtc->index % 2);
-		} else {
-			dspr = (rcrtc->index % 2) ? 3 : 1;
-			hwplanes = 1 << ((rcrtc->index % 2) ? 2 : 0);
-		}
-	}
-
 	/*
 	 * Update the planes to display timing and dot clock generator
 	 * associations.
@@ -462,8 +455,13 @@  static void rcar_du_crtc_setup(struct rcar_du_crtc *rcrtc)
 	rcar_du_crtc_set_display_timing(rcrtc);
 	rcar_du_group_set_routing(rcrtc->group);
 
-	/* Start with all planes disabled. */
-	rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR, 0);
+	/*
+	 * Start with all planes disabled, except when using the VSP in which
+	 * case the fixed plane assignment must not be modified.
+	 */
+	if (!rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
+		rcar_du_group_write(rcrtc->group,
+				    rcrtc->index % 2 ? DS2PR : DS1PR, 0);
 
 	/* Enable the VSP compositor. */
 	if (rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE))
@@ -505,8 +503,11 @@  static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc)
 	 * are stopped in one operation as we now wait for one vblank per CRTC.
 	 * Whether this can be improved needs to be researched.
 	 */
-	rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR, 0);
-	drm_crtc_wait_one_vblank(crtc);
+	if (!rcar_du_has(rcrtc->group->dev, RCAR_DU_FEATURE_VSP1_SOURCE)) {
+		rcar_du_group_write(rcrtc->group,
+				    rcrtc->index % 2 ? DS2PR : DS1PR, 0);
+		drm_crtc_wait_one_vblank(crtc);
+	}
 
 	/*
 	 * Disable vertical blanking interrupt reporting. We first need to wait
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_group.c b/drivers/gpu/drm/rcar-du/rcar_du_group.c
index 00d5f470d377..d26b647207b8 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_group.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_group.c
@@ -126,6 +126,18 @@  static void rcar_du_group_setup(struct rcar_du_group *rgrp)
 	if (rcdu->info->gen >= 3)
 		rcar_du_group_write(rgrp, DEFR10, DEFR10_CODE | DEFR10_DEFE10);
 
+	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
+		/*
+		 * The CRTCs can compose the output of a VSP with other planes
+		 * on Gen2 hardware, and of two VSPs on Gen3 hardware. Neither
+		 * of these features are supported by the driver, so we hardcode
+		 * plane assignment to CRTCs when setting the group up to avoid
+		 * the need to restart then group when setting planes up.
+		 */
+		rcar_du_group_write(rgrp, DS1PR, 1);
+		rcar_du_group_write(rgrp, DS2PR, rcdu->info->gen >= 3 ? 3 : 2);
+	}
+
 	/*
 	 * Use DS1PR and DS2PR to configure planes priorities and connects the
 	 * superposition 0 to DU0 pins. DU1 pins will be configured dynamically.
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
index 0e4e839afc97..13186a5684f1 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
@@ -562,17 +562,23 @@  int rcar_du_modeset_init(struct rcar_du_device *rcdu)
 		rgrp->index = i;
 		rgrp->num_crtcs = min(rcdu->num_crtcs - 2 * i, 2U);
 
-		/*
-		 * If we have more than one CRTCs in this group pre-associate
-		 * the low-order planes with CRTC 0 and the high-order planes
-		 * with CRTC 1 to minimize flicker occurring when the
-		 * association is changed.
-		 */
-		rgrp->dptsr_planes = rgrp->num_crtcs > 1
-				   ? (rcdu->info->gen >= 3 ? 0x04 : 0xf0)
-				   : 0;
-
-		if (!rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
+		if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE)) {
+			/*
+			 * When using the VSP plane assignment to CRTCs is
+			 * fixed. The first VSP is connected to plane 1, and the
+			 * second VSP to plane 2 on Gen2 hardware and to plane 3
+			 * on Gen3 hardware.
+			 */
+			rgrp->dptsr_planes = rgrp->num_crtcs > 1
+					   ? (rcdu->info->gen >= 3 ? 4 : 2)
+					   : 0;
+		} else {
+			/*
+			 * Pre-associate the planes with the CRTCs if we have
+			 * more than one CRTC in this group to minimize flicker
+			 * when plane association is changed.
+			 */
+			rgrp->dptsr_planes = rgrp->num_crtcs > 1 ? 0xf0 : 0x00;
 			ret = rcar_du_planes_init(rgrp);
 			if (ret < 0)
 				return ret;
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_plane.c b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
index b0040478a3db..787f036b18fb 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_plane.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_plane.c
@@ -548,17 +548,9 @@  void __rcar_du_plane_setup(struct rcar_du_group *rgrp,
 		rcar_du_plane_setup_format(rgrp, (state->hwindex + 1) % 8,
 					   state);
 
+	/* On Gen3 planes have no scanout data. */
 	if (rcdu->info->gen < 3)
 		rcar_du_plane_setup_scanout(rgrp, state);
-
-	if (state->source == RCAR_DU_PLANE_VSPD1) {
-		unsigned int vspd1_sink = rgrp->index ? 2 : 0;
-
-		if (rcdu->vspd1_sink != vspd1_sink) {
-			rcdu->vspd1_sink = vspd1_sink;
-			rcar_du_set_dpad0_vsp1_routing(rcdu);
-		}
-	}
 }
 
 static int rcar_du_plane_atomic_check(struct drm_plane *plane,
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
index e43b065e141a..dba150a20f3d 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
@@ -74,15 +74,6 @@  void rcar_du_vsp_enable(struct rcar_du_crtc *crtc)
 
 	__rcar_du_plane_setup(crtc->group, &state);
 
-	/*
-	 * Ensure that the plane source configuration takes effect by requesting
-	 * a restart of the group. See rcar_du_plane_atomic_update() for a more
-	 * detailed explanation.
-	 *
-	 * TODO: Check whether this is still needed on Gen3.
-	 */
-	crtc->group->need_restart = true;
-
 	vsp1_du_setup_lif(crtc->vsp->vsp, crtc->vsp_pipe, &cfg);
 }