[PATCH RFC v2 19/20] drm/vkms: Introduce support for post-blend color pipeline

[Louis Chauvet]

Le 18/09/2025 à 02:43, Nícolas F. R. A. Prado a écrit :
> Introduce a post-blend color pipeline with the same colorop blocks as
> the pre-blend color pipeline.
> 
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
> ---
>   drivers/gpu/drm/vkms/vkms_colorop.c  | 98 ++++++++++++++++++++++++++++++++++++
>   drivers/gpu/drm/vkms/vkms_composer.c |  5 +-
>   drivers/gpu/drm/vkms/vkms_crtc.c     |  1 +
>   drivers/gpu/drm/vkms/vkms_drv.h      |  1 +
>   4 files changed, 104 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_colorop.c b/drivers/gpu/drm/vkms/vkms_colorop.c
> index 5924ae2bd40fc904048f99bc9b96308140709e25..54c512db68eef16435d5f79453784f7784d540fb 100644
> --- a/drivers/gpu/drm/vkms/vkms_colorop.c
> +++ b/drivers/gpu/drm/vkms/vkms_colorop.c
> @@ -98,6 +98,86 @@ vkms_initialize_pre_blend_color_pipeline(struct drm_plane *plane,
>   	return ret;
>   }
>   
> +static int
> +vkms_initialize_post_blend_color_pipeline(struct drm_crtc *crtc,
> +					  struct drm_prop_enum_list *list)
> +{
> +	struct drm_colorop *ops[MAX_COLOR_PIPELINE_OPS];
> +	struct drm_device *dev = crtc->dev;
> +	int ret;
> +	int i = 0;
> +
> +	memset(ops, 0, sizeof(ops));
> +
> +	/* 1st op: 1d curve */
> +	ops[i] = kzalloc(sizeof(*ops[i]), GFP_KERNEL);
> +	if (!ops[i]) {
> +		ret = -ENOMEM;
> +		goto cleanup;
> +	}
> +
> +	ret = drm_crtc_colorop_curve_1d_init(dev, ops[i], crtc, supported_tfs,
> +					     DRM_COLOROP_FLAG_ALLOW_BYPASS);
> +	if (ret)
> +		goto cleanup;
> +
> +	list->type = ops[i]->base.id;
> +	list->name = kasprintf(GFP_KERNEL, "Color Pipeline %d", ops[i]->base.id);
> +
> +	i++;
> +
> +	/* 2nd op: 3x4 matrix */
> +	ops[i] = kzalloc(sizeof(*ops[i]), GFP_KERNEL);
> +	if (!ops[i]) {
> +		ret = -ENOMEM;
> +		goto cleanup;
> +	}
> +
> +	ret = drm_crtc_colorop_ctm_3x4_init(dev, ops[i], crtc, DRM_COLOROP_FLAG_ALLOW_BYPASS);
> +	if (ret)
> +		goto cleanup;
> +
> +	drm_colorop_set_next_property(ops[i - 1], ops[i]);
> +
> +	i++;
> +
> +	/* 3rd op: 3x4 matrix */
> +	ops[i] = kzalloc(sizeof(*ops[i]), GFP_KERNEL);
> +	if (!ops[i]) {
> +		ret = -ENOMEM;
> +		goto cleanup;
> +	}
> +
> +	ret = drm_crtc_colorop_ctm_3x4_init(dev, ops[i], crtc, DRM_COLOROP_FLAG_ALLOW_BYPASS);
> +	if (ret)
> +		goto cleanup;
> +
> +	drm_colorop_set_next_property(ops[i - 1], ops[i]);
> +
> +	i++;
> +
> +	/* 4th op: 1d curve */
> +	ops[i] = kzalloc(sizeof(*ops[i]), GFP_KERNEL);
> +	if (!ops[i]) {
> +		ret = -ENOMEM;
> +		goto cleanup;
> +	}
> +
> +	ret = drm_crtc_colorop_curve_1d_init(dev, ops[i], crtc, supported_tfs,
> +					     DRM_COLOROP_FLAG_ALLOW_BYPASS);
> +	if (ret)
> +		goto cleanup;
> +
> +	drm_colorop_set_next_property(ops[i - 1], ops[i]);
> +
> +	return 0;
> +
> +cleanup:
> +	drm_colorop_pipeline_destroy(dev);

Same comment as for pre_blend colorops, it feel strange to destroy all 
the pipelines here.

The suggestion in [1] is better (don't forget to add the kfree).

[1]: 
https://lore.kernel.org/all/73f01810-df2d-4e39-a20b-fc1cec2c5e12@amd.com/

> +	return ret;
> +}
> +
>   int vkms_initialize_pre_blend_colorops(struct drm_plane *plane)
>   {
>   	struct drm_prop_enum_list pipeline;
> @@ -115,3 +195,21 @@ int vkms_initialize_pre_blend_colorops(struct drm_plane *plane)
>   
>   	return 0;
>   }
> +
> +int vkms_initialize_post_blend_colorops(struct drm_crtc *crtc)
> +{
> +	struct drm_prop_enum_list pipeline;
> +	int ret;
> +
> +	/* Add color pipeline */
> +	ret = vkms_initialize_post_blend_color_pipeline(crtc, &pipeline);
> +	if (ret)
> +		return ret;
> +
> +	/* Create COLOR_PIPELINE property and attach */
> +	ret = drm_crtc_create_color_pipeline_property(crtc, &pipeline, 1);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> index 05e1551d6330e4dc14563d3a399b3544d11c6576..efe09538768b01108a305f0ace765246220b487b 100644
> --- a/drivers/gpu/drm/vkms/vkms_composer.c
> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> @@ -495,7 +495,10 @@ static void blend(struct vkms_writeback_job *wb,
>   			blend_line(plane[i], y, crtc_x_limit, stage_buffer, output_buffer);
>   		}
>   
> -		apply_lut(crtc_state, output_buffer);
> +		if (crtc_state->base.color_pipeline_enabled)
> +			color_transform(crtc_state->base.color_pipeline, output_buffer);
> +		else
> +			apply_lut(crtc_state, output_buffer);
>   
>   		*crc32 = crc32_le(*crc32, (void *)output_buffer->pixels, row_size);
>   
> diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> index e60573e0f3e9510252e1f198b00e28bcc7987620..04737c1fb70e4f0aef480a180e57a76fbc279dfa 100644
> --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> @@ -295,6 +295,7 @@ struct vkms_output *vkms_crtc_init(struct drm_device *dev, struct drm_plane *pri
>   	}
>   
>   	drm_crtc_enable_color_mgmt(crtc, 0, false, VKMS_LUT_SIZE);
> +	vkms_initialize_post_blend_colorops(crtc);
>   
>   	spin_lock_init(&vkms_out->lock);
>   	spin_lock_init(&vkms_out->composer_lock);
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index 37ee569474223b2cf01e3cc0e4f119777533ae23..a0308c2263d1858a72906853960ea7d1bbecd03e 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -306,5 +306,6 @@ int vkms_enable_writeback_connector(struct vkms_device *vkmsdev, struct vkms_out
>   
>   /* Colorops */
>   int vkms_initialize_pre_blend_colorops(struct drm_plane *plane);
> +int vkms_initialize_post_blend_colorops(struct drm_crtc *crtc);
>   
>   #endif /* _VKMS_DRV_H_ */
> 

-- 
--
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com