[PATCH v2 0/3] Add DRM pixel blend mode support to R-Car DU

[PATCH v2 0/3] Add DRM pixel blend mode support to R-Car DU

[Takanari Hayama]

The series of patches adds support for DRM pixel blend mode to R-Car DU
driver. The current R-Car DU implicitly supports "Coverage" only.

Unfortunately, this changes the default blending mode of R-Car DU to
"Pre-multiplied" which is the default when pixel blend mode is
supported.

v2:
 vsp1:
 - Add a premult flag instead of blend mode enum
 rcar-du:
 - Support DRM_MODE_BLEND_PREMULTI via the premult flag
 - Support DRM_MODE_BLEND_PIXEL_NONE via format override [1]

[1] https://lore.kernel.org/linux-renesas-soc/20220704025231.3911138-1-taki@igel.co.jp/T/#m3351cb5965cd5bf2d416fa5ca5007773260205bd

Takanari Hayama (3):
  media: vsp1: add premultiplied alpha support
  drm: rcar-du: Add DRM_MODE_BLEND_PREMULTI support
  drm: rcar-du: Add DRM_MODE_BLEND_PIXEL_NONE support

 drivers/gpu/drm/rcar-du/rcar_du_vsp.c         | 26 ++++++++++++++++++-
 .../media/platform/renesas/vsp1/vsp1_drm.c    |  2 ++
 include/media/vsp1.h                          |  2 ++
 3 files changed, 29 insertions(+), 1 deletion(-)

-- 
2.25.1

[PATCH v2 1/3] media: vsp1: add premultiplied alpha support

[Takanari Hayama]

To support DRM blend mode in R-Car DU driver, we must be able to pass
a plane with the premultiplied alpha. Adding a new property to
vsp1_du_atomic_config allows the R-Car DU driver to pass the
premultiplied alpha plane.

Signed-off-by: Takanari Hayama <taki@igel.co.jp>
---
 drivers/media/platform/renesas/vsp1/vsp1_drm.c | 2 ++
 include/media/vsp1.h                           | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drm.c b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
index 0c2507dc03d6..019e18976bd8 100644
--- a/drivers/media/platform/renesas/vsp1/vsp1_drm.c
+++ b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
@@ -856,6 +856,8 @@ int vsp1_du_atomic_update(struct device *dev, unsigned int pipe_index,
 	rpf->mem.addr[1] = cfg->mem[1];
 	rpf->mem.addr[2] = cfg->mem[2];
 
+	rpf->format.flags = (cfg->premult) ? V4L2_PIX_FMT_FLAG_PREMUL_ALPHA : 0;
+
 	vsp1->drm->inputs[rpf_index].crop = cfg->src;
 	vsp1->drm->inputs[rpf_index].compose = cfg->dst;
 	vsp1->drm->inputs[rpf_index].zpos = cfg->zpos;
diff --git a/include/media/vsp1.h b/include/media/vsp1.h
index cc1b0d42ce95..48f4a5023d81 100644
--- a/include/media/vsp1.h
+++ b/include/media/vsp1.h
@@ -51,6 +51,7 @@ int vsp1_du_setup_lif(struct device *dev, unsigned int pipe_index,
  * @dst: destination rectangle on the display (integer coordinates)
  * @alpha: alpha value (0: fully transparent, 255: fully opaque)
  * @zpos: Z position of the plane (from 0 to number of planes minus 1)
+ * @premult: true for premultiplied alpha
  */
 struct vsp1_du_atomic_config {
 	u32 pixelformat;
@@ -60,6 +61,7 @@ struct vsp1_du_atomic_config {
 	struct v4l2_rect dst;
 	unsigned int alpha;
 	unsigned int zpos;
+	bool premult;
 };
 
 /**
-- 
2.25.1

Re: [PATCH v2 1/3] media: vsp1: add premultiplied alpha support

[Sergey Shtylyov]

Hello!

On 8/10/22 11:37 AM, Takanari Hayama wrote:

> To support DRM blend mode in R-Car DU driver, we must be able to pass
> a plane with the premultiplied alpha. Adding a new property to
> vsp1_du_atomic_config allows the R-Car DU driver to pass the
> premultiplied alpha plane.
> 
> Signed-off-by: Takanari Hayama <taki@igel.co.jp>
> ---
>  drivers/media/platform/renesas/vsp1/vsp1_drm.c | 2 ++
>  include/media/vsp1.h                           | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drm.c b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> index 0c2507dc03d6..019e18976bd8 100644
> --- a/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> +++ b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> @@ -856,6 +856,8 @@ int vsp1_du_atomic_update(struct device *dev, unsigned int pipe_index,
>  	rpf->mem.addr[1] = cfg->mem[1];
>  	rpf->mem.addr[2] = cfg->mem[2];
>  
> +	rpf->format.flags = (cfg->premult) ? V4L2_PIX_FMT_FLAG_PREMUL_ALPHA : 0;
> +

  Parens are hardly needed here... :-)

[...]

MBR, Sergey

Re: [PATCH v2 1/3] media: vsp1: add premultiplied alpha support

[Takanari Hayama]

Hi,

> 2022/08/11 2:41、Sergey Shtylyov <s.shtylyov@omp.ru>のメール:
> 
> Hello!
> 
> On 8/10/22 11:37 AM, Takanari Hayama wrote:
> 
>> To support DRM blend mode in R-Car DU driver, we must be able to pass
>> a plane with the premultiplied alpha. Adding a new property to
>> vsp1_du_atomic_config allows the R-Car DU driver to pass the
>> premultiplied alpha plane.
>> 
>> Signed-off-by: Takanari Hayama <taki@igel.co.jp>
>> ---
>> drivers/media/platform/renesas/vsp1/vsp1_drm.c | 2 ++
>> include/media/vsp1.h                           | 2 ++
>> 2 files changed, 4 insertions(+)
>> 
>> diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drm.c b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
>> index 0c2507dc03d6..019e18976bd8 100644
>> --- a/drivers/media/platform/renesas/vsp1/vsp1_drm.c
>> +++ b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
>> @@ -856,6 +856,8 @@ int vsp1_du_atomic_update(struct device *dev, unsigned int pipe_index,
>> 	rpf->mem.addr[1] = cfg->mem[1];
>> 	rpf->mem.addr[2] = cfg->mem[2];
>> 
>> +	rpf->format.flags = (cfg->premult) ? V4L2_PIX_FMT_FLAG_PREMUL_ALPHA : 0;
>> +
> 
>  Parens are hardly needed here... :-)

True. :) Thank you.

Cheers,
Takanari Hayama, Ph.D. <taki@igel.co.jp>
IGEL Co., Ltd.
https://www.igel.co.jp/

Re: [PATCH v2 1/3] media: vsp1: add premultiplied alpha support

[Laurent Pinchart]

Hi Hayama-san,

Thank you for the patch.

On Wed, Aug 10, 2022 at 05:37:09PM +0900, Takanari Hayama wrote:
> To support DRM blend mode in R-Car DU driver, we must be able to pass
> a plane with the premultiplied alpha. Adding a new property to
> vsp1_du_atomic_config allows the R-Car DU driver to pass the
> premultiplied alpha plane.
> 
> Signed-off-by: Takanari Hayama <taki@igel.co.jp>
> ---
>  drivers/media/platform/renesas/vsp1/vsp1_drm.c | 2 ++
>  include/media/vsp1.h                           | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drm.c b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> index 0c2507dc03d6..019e18976bd8 100644
> --- a/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> +++ b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> @@ -856,6 +856,8 @@ int vsp1_du_atomic_update(struct device *dev, unsigned int pipe_index,
>  	rpf->mem.addr[1] = cfg->mem[1];
>  	rpf->mem.addr[2] = cfg->mem[2];
>  
> +	rpf->format.flags = (cfg->premult) ? V4L2_PIX_FMT_FLAG_PREMUL_ALPHA : 0;

I'll drop the parentheses when applying.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +
>  	vsp1->drm->inputs[rpf_index].crop = cfg->src;
>  	vsp1->drm->inputs[rpf_index].compose = cfg->dst;
>  	vsp1->drm->inputs[rpf_index].zpos = cfg->zpos;
> diff --git a/include/media/vsp1.h b/include/media/vsp1.h
> index cc1b0d42ce95..48f4a5023d81 100644
> --- a/include/media/vsp1.h
> +++ b/include/media/vsp1.h
> @@ -51,6 +51,7 @@ int vsp1_du_setup_lif(struct device *dev, unsigned int pipe_index,
>   * @dst: destination rectangle on the display (integer coordinates)
>   * @alpha: alpha value (0: fully transparent, 255: fully opaque)
>   * @zpos: Z position of the plane (from 0 to number of planes minus 1)
> + * @premult: true for premultiplied alpha
>   */
>  struct vsp1_du_atomic_config {
>  	u32 pixelformat;
> @@ -60,6 +61,7 @@ struct vsp1_du_atomic_config {
>  	struct v4l2_rect dst;
>  	unsigned int alpha;
>  	unsigned int zpos;
> +	bool premult;
>  };
>  
>  /**

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2 1/3] media: vsp1: add premultiplied alpha support

[Takanari Hayama]

Hi Laurent,

> 2022/08/19 11:01、Laurent Pinchart <laurent.pinchart@ideasonboard.com>のメール:
> 
> Hi Hayama-san,
> 
> Thank you for the patch.
> 
> On Wed, Aug 10, 2022 at 05:37:09PM +0900, Takanari Hayama wrote:
>> To support DRM blend mode in R-Car DU driver, we must be able to pass
>> a plane with the premultiplied alpha. Adding a new property to
>> vsp1_du_atomic_config allows the R-Car DU driver to pass the
>> premultiplied alpha plane.
>> 
>> Signed-off-by: Takanari Hayama <taki@igel.co.jp>
>> ---
>> drivers/media/platform/renesas/vsp1/vsp1_drm.c | 2 ++
>> include/media/vsp1.h                           | 2 ++
>> 2 files changed, 4 insertions(+)
>> 
>> diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drm.c b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
>> index 0c2507dc03d6..019e18976bd8 100644
>> --- a/drivers/media/platform/renesas/vsp1/vsp1_drm.c
>> +++ b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
>> @@ -856,6 +856,8 @@ int vsp1_du_atomic_update(struct device *dev, unsigned int pipe_index,
>> 	rpf->mem.addr[1] = cfg->mem[1];
>> 	rpf->mem.addr[2] = cfg->mem[2];
>> 
>> +	rpf->format.flags = (cfg->premult) ? V4L2_PIX_FMT_FLAG_PREMUL_ALPHA : 0;
> 
> I'll drop the parentheses when applying.

Thank you!

> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
>> +
>> 	vsp1->drm->inputs[rpf_index].crop = cfg->src;
>> 	vsp1->drm->inputs[rpf_index].compose = cfg->dst;
>> 	vsp1->drm->inputs[rpf_index].zpos = cfg->zpos;
>> diff --git a/include/media/vsp1.h b/include/media/vsp1.h
>> index cc1b0d42ce95..48f4a5023d81 100644
>> --- a/include/media/vsp1.h
>> +++ b/include/media/vsp1.h
>> @@ -51,6 +51,7 @@ int vsp1_du_setup_lif(struct device *dev, unsigned int pipe_index,
>>  * @dst: destination rectangle on the display (integer coordinates)
>>  * @alpha: alpha value (0: fully transparent, 255: fully opaque)
>>  * @zpos: Z position of the plane (from 0 to number of planes minus 1)
>> + * @premult: true for premultiplied alpha
>>  */
>> struct vsp1_du_atomic_config {
>> 	u32 pixelformat;
>> @@ -60,6 +61,7 @@ struct vsp1_du_atomic_config {
>> 	struct v4l2_rect dst;
>> 	unsigned int alpha;
>> 	unsigned int zpos;
>> +	bool premult;
>> };
>> 
>> /**
> 
> -- 
> Regards,
> 
> Laurent Pinchart

Cheers,
Takanari Hayama, Ph.D. <taki@igel.co.jp>
IGEL Co., Ltd.
https://www.igel.co.jp/

Re: [PATCH v2 1/3] media: vsp1: add premultiplied alpha support

[Laurent Pinchart]

Mauro, would you be fine with this patch going through the DRM tree for
v6.1 ? I don't foresee any risk of conflict with other changes to the
VSP driver scheduled for the next kernel version. If that's fine with
you, could you give an Acked-by ? Otherwise I can send you a pull
request to create an immutable branch and base the rest on it in my pull
request for DRM, but given how small this change is, it seems a bit
overkill.

On Fri, Aug 19, 2022 at 05:01:10AM +0300, Laurent Pinchart wrote:
> Hi Hayama-san,
> 
> Thank you for the patch.
> 
> On Wed, Aug 10, 2022 at 05:37:09PM +0900, Takanari Hayama wrote:
> > To support DRM blend mode in R-Car DU driver, we must be able to pass
> > a plane with the premultiplied alpha. Adding a new property to
> > vsp1_du_atomic_config allows the R-Car DU driver to pass the
> > premultiplied alpha plane.
> > 
> > Signed-off-by: Takanari Hayama <taki@igel.co.jp>
> > ---
> >  drivers/media/platform/renesas/vsp1/vsp1_drm.c | 2 ++
> >  include/media/vsp1.h                           | 2 ++
> >  2 files changed, 4 insertions(+)
> > 
> > diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drm.c b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> > index 0c2507dc03d6..019e18976bd8 100644
> > --- a/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> > +++ b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> > @@ -856,6 +856,8 @@ int vsp1_du_atomic_update(struct device *dev, unsigned int pipe_index,
> >  	rpf->mem.addr[1] = cfg->mem[1];
> >  	rpf->mem.addr[2] = cfg->mem[2];
> >  
> > +	rpf->format.flags = (cfg->premult) ? V4L2_PIX_FMT_FLAG_PREMUL_ALPHA : 0;
> 
> I'll drop the parentheses when applying.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> > +
> >  	vsp1->drm->inputs[rpf_index].crop = cfg->src;
> >  	vsp1->drm->inputs[rpf_index].compose = cfg->dst;
> >  	vsp1->drm->inputs[rpf_index].zpos = cfg->zpos;
> > diff --git a/include/media/vsp1.h b/include/media/vsp1.h
> > index cc1b0d42ce95..48f4a5023d81 100644
> > --- a/include/media/vsp1.h
> > +++ b/include/media/vsp1.h
> > @@ -51,6 +51,7 @@ int vsp1_du_setup_lif(struct device *dev, unsigned int pipe_index,
> >   * @dst: destination rectangle on the display (integer coordinates)
> >   * @alpha: alpha value (0: fully transparent, 255: fully opaque)
> >   * @zpos: Z position of the plane (from 0 to number of planes minus 1)
> > + * @premult: true for premultiplied alpha
> >   */
> >  struct vsp1_du_atomic_config {
> >  	u32 pixelformat;
> > @@ -60,6 +61,7 @@ struct vsp1_du_atomic_config {
> >  	struct v4l2_rect dst;
> >  	unsigned int alpha;
> >  	unsigned int zpos;
> > +	bool premult;
> >  };
> >  
> >  /**

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2 1/3] media: vsp1: add premultiplied alpha support

[Mauro Carvalho Chehab]

Em Fri, 19 Aug 2022 05:38:28 +0300
Laurent Pinchart <laurent.pinchart@ideasonboard.com> escreveu:

> Mauro, would you be fine with this patch going through the DRM tree for
> v6.1 ? I don't foresee any risk of conflict with other changes to the
> VSP driver scheduled for the next kernel version. If that's fine with
> you, could you give an Acked-by ? Otherwise I can send you a pull
> request to create an immutable branch and base the rest on it in my pull
> request for DRM, but given how small this change is, it seems a bit
> overkill.

Please, don't top-post.
> 
> On Fri, Aug 19, 2022 at 05:01:10AM +0300, Laurent Pinchart wrote:
> > Hi Hayama-san,
> > 
> > Thank you for the patch.
> > 
> > On Wed, Aug 10, 2022 at 05:37:09PM +0900, Takanari Hayama wrote:  
> > > To support DRM blend mode in R-Car DU driver, we must be able to pass
> > > a plane with the premultiplied alpha. Adding a new property to
> > > vsp1_du_atomic_config allows the R-Car DU driver to pass the
> > > premultiplied alpha plane.
> > > 
> > > Signed-off-by: Takanari Hayama <taki@igel.co.jp>

Sure, this can be merged via DRM tree.


> > > ---
> > >  drivers/media/platform/renesas/vsp1/vsp1_drm.c | 2 ++
> > >  include/media/vsp1.h                           | 2 ++
> > >  2 files changed, 4 insertions(+)
> > > 
> > > diff --git a/drivers/media/platform/renesas/vsp1/vsp1_drm.c b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> > > index 0c2507dc03d6..019e18976bd8 100644
> > > --- a/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> > > +++ b/drivers/media/platform/renesas/vsp1/vsp1_drm.c
> > > @@ -856,6 +856,8 @@ int vsp1_du_atomic_update(struct device *dev, unsigned int pipe_index,
> > >  	rpf->mem.addr[1] = cfg->mem[1];
> > >  	rpf->mem.addr[2] = cfg->mem[2];
> > >  
> > > +	rpf->format.flags = (cfg->premult) ? V4L2_PIX_FMT_FLAG_PREMUL_ALPHA : 0;  
> > 
> > I'll drop the parentheses when applying.
> > 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

With this change:

Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Regards,
Mauro

[PATCH v2 2/3] drm: rcar-du: Add DRM_MODE_BLEND_PREMULTI support

[Takanari Hayama]

R-Car DU driver implicitly supports DRM_MODE_BLEND_COVERAGE only.
This adds a support for DRM_MODE_BLEND_PREMULTI. As a consequence,
DRM_MODE_BLEND_PREMULTI becomes the default. If DRM_MODE_BLEND_COVERAGE
is desired, it should be set explicitly.

This behavior comes from how DRM blend mode is supported.
drm_plane_create_blend_mode_property() creates the blend mode property
with the default value of DRM_MODE_BLEND_PREMULTI. This default value
cannot be modified from the atomic driver.

Signed-off-by: Takanari Hayama <taki@igel.co.jp>
---
 drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
index 8eb9b2b097ae..b9580fcfec7a 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
@@ -167,6 +167,8 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
 		cfg.mem[i] = sg_dma_address(state->sg_tables[i].sgl)
 			   + fb->offsets[i];
 
+	cfg.premult = (state->state.pixel_blend_mode == DRM_MODE_BLEND_PREMULTI);
+
 	format = rcar_du_format_info(state->format->fourcc);
 	cfg.pixelformat = format->v4l2;
 
@@ -444,6 +446,10 @@ int rcar_du_vsp_init(struct rcar_du_vsp *vsp, struct device_node *np,
 						       num_planes - 1);
 		}
 
+		drm_plane_create_blend_mode_property(&plane->plane,
+					BIT(DRM_MODE_BLEND_PREMULTI) |
+					BIT(DRM_MODE_BLEND_COVERAGE));
+
 		vsp->num_planes++;
 	}
 
-- 
2.25.1

Re: [PATCH v2 2/3] drm: rcar-du: Add DRM_MODE_BLEND_PREMULTI support

[Laurent Pinchart]

Hello Hayama-san,

Thank you for the patch.

On Wed, Aug 10, 2022 at 05:37:10PM +0900, Takanari Hayama wrote:
> R-Car DU driver implicitly supports DRM_MODE_BLEND_COVERAGE only.
> This adds a support for DRM_MODE_BLEND_PREMULTI. As a consequence,
> DRM_MODE_BLEND_PREMULTI becomes the default. If DRM_MODE_BLEND_COVERAGE
> is desired, it should be set explicitly.
> 
> This behavior comes from how DRM blend mode is supported.
> drm_plane_create_blend_mode_property() creates the blend mode property
> with the default value of DRM_MODE_BLEND_PREMULTI. This default value
> cannot be modified from the atomic driver.
> 
> Signed-off-by: Takanari Hayama <taki@igel.co.jp>
> ---
>  drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> index 8eb9b2b097ae..b9580fcfec7a 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> @@ -167,6 +167,8 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
>  		cfg.mem[i] = sg_dma_address(state->sg_tables[i].sgl)
>  			   + fb->offsets[i];
>  
> +	cfg.premult = (state->state.pixel_blend_mode == DRM_MODE_BLEND_PREMULTI);

I'll drop the parentheses here too, and if you don't mind, I'll move
this down after setting cfg.pixelformat, as premult qualifies the format
so it's more logical in that reading order (no change on the behaviour
of course).

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +
>  	format = rcar_du_format_info(state->format->fourcc);
>  	cfg.pixelformat = format->v4l2;
>  
> @@ -444,6 +446,10 @@ int rcar_du_vsp_init(struct rcar_du_vsp *vsp, struct device_node *np,
>  						       num_planes - 1);
>  		}
>  
> +		drm_plane_create_blend_mode_property(&plane->plane,
> +					BIT(DRM_MODE_BLEND_PREMULTI) |
> +					BIT(DRM_MODE_BLEND_COVERAGE));
> +
>  		vsp->num_planes++;
>  	}
>  

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2 2/3] drm: rcar-du: Add DRM_MODE_BLEND_PREMULTI support

[Takanari Hayama]

Hi Laurent,

> 2022/08/19 11:08、Laurent Pinchart <laurent.pinchart@ideasonboard.com>のメール:
> 
> Hello Hayama-san,
> 
> Thank you for the patch.
> 
> On Wed, Aug 10, 2022 at 05:37:10PM +0900, Takanari Hayama wrote:
>> R-Car DU driver implicitly supports DRM_MODE_BLEND_COVERAGE only.
>> This adds a support for DRM_MODE_BLEND_PREMULTI. As a consequence,
>> DRM_MODE_BLEND_PREMULTI becomes the default. If DRM_MODE_BLEND_COVERAGE
>> is desired, it should be set explicitly.
>> 
>> This behavior comes from how DRM blend mode is supported.
>> drm_plane_create_blend_mode_property() creates the blend mode property
>> with the default value of DRM_MODE_BLEND_PREMULTI. This default value
>> cannot be modified from the atomic driver.
>> 
>> Signed-off-by: Takanari Hayama <taki@igel.co.jp>
>> ---
>> drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
>> index 8eb9b2b097ae..b9580fcfec7a 100644
>> --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
>> +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
>> @@ -167,6 +167,8 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
>> 		cfg.mem[i] = sg_dma_address(state->sg_tables[i].sgl)
>> 			   + fb->offsets[i];
>> 
>> +	cfg.premult = (state->state.pixel_blend_mode == DRM_MODE_BLEND_PREMULTI);
> 
> I'll drop the parentheses here too, and if you don't mind, I'll move
> this down after setting cfg.pixelformat, as premult qualifies the format
> so it's more logical in that reading order (no change on the behaviour
> of course).

Thank you. I also agree with the proposed change in order.

> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
>> +
>> 	format = rcar_du_format_info(state->format->fourcc);
>> 	cfg.pixelformat = format->v4l2;
>> 
>> @@ -444,6 +446,10 @@ int rcar_du_vsp_init(struct rcar_du_vsp *vsp, struct device_node *np,
>> 						       num_planes - 1);
>> 		}
>> 
>> +		drm_plane_create_blend_mode_property(&plane->plane,
>> +					BIT(DRM_MODE_BLEND_PREMULTI) |
>> +					BIT(DRM_MODE_BLEND_COVERAGE));
>> +
>> 		vsp->num_planes++;
>> 	}
>> 
> 
> -- 
> Regards,
> 
> Laurent Pinchart

Cheers,
Takanari Hayama, Ph.D. <taki@igel.co.jp>
IGEL Co., Ltd.
https://www.igel.co.jp/

[PATCH v2 3/3] drm: rcar-du: Add DRM_MODE_BLEND_PIXEL_NONE support

[Takanari Hayama]

DRM_MODE_BLEND_PIXEL_NONE ignores an alpha channel.

Rcar-du driver supports only 3 formats with an alpha channel
(DRM_FORMAT_ARGB1555, DRM_FORMAT_ARGB8888 and DRM_FORMAT_ARGB4444). We
simply override the format passed to VSP1 for blending with the pixel
format without alpha channel.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Takanari Hayama <taki@igel.co.jp>
---
 drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
index b9580fcfec7a..7cce2d414ced 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
@@ -151,6 +151,7 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
 		.alpha = state->state.alpha >> 8,
 		.zpos = state->state.zpos,
 	};
+	u32 fourcc = state->format->fourcc;
 	unsigned int i;
 
 	cfg.src.left = state->state.src.x1 >> 16;
@@ -169,7 +170,23 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
 
 	cfg.premult = (state->state.pixel_blend_mode == DRM_MODE_BLEND_PREMULTI);
 
-	format = rcar_du_format_info(state->format->fourcc);
+	if (state->state.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE) {
+		switch (fourcc) {
+		case DRM_FORMAT_ARGB1555:
+			fourcc = DRM_FORMAT_XRGB1555;
+			break;
+
+		case DRM_FORMAT_ARGB4444:
+			fourcc = DRM_FORMAT_XRGB4444;
+			break;
+
+		case DRM_FORMAT_ARGB8888:
+			fourcc = DRM_FORMAT_XRGB8888;
+			break;
+		}
+	}
+
+	format = rcar_du_format_info(fourcc);
 	cfg.pixelformat = format->v4l2;
 
 	vsp1_du_atomic_update(plane->vsp->vsp, crtc->vsp_pipe,
@@ -447,6 +464,7 @@ int rcar_du_vsp_init(struct rcar_du_vsp *vsp, struct device_node *np,
 		}
 
 		drm_plane_create_blend_mode_property(&plane->plane,
+					BIT(DRM_MODE_BLEND_PIXEL_NONE) |
 					BIT(DRM_MODE_BLEND_PREMULTI) |
 					BIT(DRM_MODE_BLEND_COVERAGE));
 
-- 
2.25.1

Re: [PATCH v2 3/3] drm: rcar-du: Add DRM_MODE_BLEND_PIXEL_NONE support

[Laurent Pinchart]

Hello Hayama-san,

Thank you for the patch.

On Wed, Aug 10, 2022 at 05:37:11PM +0900, Takanari Hayama wrote:
> DRM_MODE_BLEND_PIXEL_NONE ignores an alpha channel.
> 
> Rcar-du driver supports only 3 formats with an alpha channel
> (DRM_FORMAT_ARGB1555, DRM_FORMAT_ARGB8888 and DRM_FORMAT_ARGB4444). We
> simply override the format passed to VSP1 for blending with the pixel
> format without alpha channel.
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Takanari Hayama <taki@igel.co.jp>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> index b9580fcfec7a..7cce2d414ced 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c
> @@ -151,6 +151,7 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
>  		.alpha = state->state.alpha >> 8,
>  		.zpos = state->state.zpos,
>  	};
> +	u32 fourcc = state->format->fourcc;
>  	unsigned int i;
>  
>  	cfg.src.left = state->state.src.x1 >> 16;
> @@ -169,7 +170,23 @@ static void rcar_du_vsp_plane_setup(struct rcar_du_vsp_plane *plane)
>  
>  	cfg.premult = (state->state.pixel_blend_mode == DRM_MODE_BLEND_PREMULTI);
>  
> -	format = rcar_du_format_info(state->format->fourcc);
> +	if (state->state.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE) {
> +		switch (fourcc) {
> +		case DRM_FORMAT_ARGB1555:
> +			fourcc = DRM_FORMAT_XRGB1555;
> +			break;
> +
> +		case DRM_FORMAT_ARGB4444:
> +			fourcc = DRM_FORMAT_XRGB4444;
> +			break;
> +
> +		case DRM_FORMAT_ARGB8888:
> +			fourcc = DRM_FORMAT_XRGB8888;
> +			break;
> +		}
> +	}
> +
> +	format = rcar_du_format_info(fourcc);
>  	cfg.pixelformat = format->v4l2;
>  
>  	vsp1_du_atomic_update(plane->vsp->vsp, crtc->vsp_pipe,
> @@ -447,6 +464,7 @@ int rcar_du_vsp_init(struct rcar_du_vsp *vsp, struct device_node *np,
>  		}
>  
>  		drm_plane_create_blend_mode_property(&plane->plane,
> +					BIT(DRM_MODE_BLEND_PIXEL_NONE) |
>  					BIT(DRM_MODE_BLEND_PREMULTI) |
>  					BIT(DRM_MODE_BLEND_COVERAGE));
>  

-- 
Regards,

Laurent Pinchart