Message-ID: <de8388d2-5625-2737-3997-4fa23baa3693@linaro.org>
Date:   Mon, 31 Jul 2023 07:01:30 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Jessica Zhang <quic_jesszhan@...cinc.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>
Cc:     quic_abhinavk@...cinc.com, ppaalanen@...il.com,
        contact@...rsion.fr, laurent.pinchart@...asonboard.com,
        sebastian.wick@...hat.com, ville.syrjala@...ux.intel.com,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, freedreno@...ts.freedesktop.org,
        wayland-devel@...ts.freedesktop.org
Subject: Re: [PATCH RFC v5 02/10] drm: Introduce solid fill DRM plane property

On 28/07/2023 20:02, Jessica Zhang wrote:
> Document and add support for solid_fill property to drm_plane. In
> addition, add support for setting and getting the values for solid_fill.
> 
> To enable solid fill planes, userspace must assign a property blob to
> the "solid_fill" plane property containing the following information:
> 
> struct drm_mode_solid_fill {
> 	u32 version;
> 	u32 r, g, b;
> };
> 
> Signed-off-by: Jessica Zhang <quic_jesszhan@...cinc.com>
> ---
>   drivers/gpu/drm/drm_atomic_state_helper.c |  9 +++++
>   drivers/gpu/drm/drm_atomic_uapi.c         | 55 +++++++++++++++++++++++++++++++
>   drivers/gpu/drm/drm_blend.c               | 30 +++++++++++++++++
>   include/drm/drm_blend.h                   |  1 +
>   include/drm/drm_plane.h                   | 35 ++++++++++++++++++++
>   include/uapi/drm/drm_mode.h               | 24 ++++++++++++++
>   6 files changed, 154 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
> index 01638c51ce0a..86fb876efbe6 100644
> --- a/drivers/gpu/drm/drm_atomic_state_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
> @@ -254,6 +254,11 @@ void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *plane_state,
>   	plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
>   	plane_state->pixel_source = DRM_PLANE_PIXEL_SOURCE_FB;
>   
> +	if (plane_state->solid_fill_blob) {
> +		drm_property_blob_put(plane_state->solid_fill_blob);
> +		plane_state->solid_fill_blob = NULL;
> +	}
> +
>   	if (plane->color_encoding_property) {
>   		if (!drm_object_property_get_default_value(&plane->base,
>   							   plane->color_encoding_property,
> @@ -336,6 +341,9 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
>   	if (state->fb)
>   		drm_framebuffer_get(state->fb);
>   
> +	if (state->solid_fill_blob)
> +		drm_property_blob_get(state->solid_fill_blob);
> +
>   	state->fence = NULL;
>   	state->commit = NULL;
>   	state->fb_damage_clips = NULL;
> @@ -385,6 +393,7 @@ void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state)
>   		drm_crtc_commit_put(state->commit);
>   
>   	drm_property_blob_put(state->fb_damage_clips);
> +	drm_property_blob_put(state->solid_fill_blob);
>   }
>   EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);
>   
> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
> index 454f980e16c9..039686c78c2a 100644
> --- a/drivers/gpu/drm/drm_atomic_uapi.c
> +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> @@ -316,6 +316,51 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
>   }
>   EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector);
>   
> +static int drm_atomic_set_solid_fill_prop(struct drm_plane_state *state,
> +		struct drm_property_blob *blob)
> +{
> +	int blob_version;
> +
> +	if (blob == state->solid_fill_blob)
> +		return 0;
> +
> +	if (blob) {
> +		struct drm_mode_solid_fill *user_info = (struct drm_mode_solid_fill *)blob->data;
> +
> +		if (blob->length != sizeof(struct drm_mode_solid_fill)) {
> +			drm_dbg_atomic(state->plane->dev,
> +				       "[PLANE:%d:%s] bad solid fill blob length: %zu\n",
> +				       state->plane->base.id, state->plane->name,
> +				       blob->length);
> +			return -EINVAL;
> +		}
> +
> +		blob_version = user_info->version;

I remember that we had versioning for quite some time. However it stroke 
me while reviewing that we do not a way to negotiate supported 
SOLID_FILL versions. However as we now have support for different 
pixel_source properties, maybe we can drop version completely. If at 
some point a driver needs to support different kind of SOLID_FILL 
property (consider v2), we can add new pixel source to the enum.

> +
> +		/* Add more versions if necessary */
> +		if (blob_version == 1) {
> +			state->solid_fill.r = user_info->r;
> +			state->solid_fill.g = user_info->g;
> +			state->solid_fill.b = user_info->b;
> +		} else {
> +			drm_dbg_atomic(state->plane->dev,
> +				       "[PLANE:%d:%s] unsupported solid fill version (version=%d)\n",
> +				       state->plane->base.id, state->plane->name,
> +				       blob_version);
> +			return -EINVAL;
> +		}
> +	}
> +
> +	drm_property_blob_put(state->solid_fill_blob);
> +
> +	if (blob)
> +		state->solid_fill_blob = drm_property_blob_get(blob);
> +	else
> +		state->solid_fill_blob = NULL;
> +
> +	return 0;
> +}
> +
>   static void set_out_fence_for_crtc(struct drm_atomic_state *state,
>   				   struct drm_crtc *crtc, s32 __user *fence_ptr)
>   {
> @@ -546,6 +591,13 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane,
>   		state->src_h = val;
>   	} else if (property == plane->pixel_source_property) {
>   		state->pixel_source = val;
> +	} else if (property == plane->solid_fill_property) {
> +		struct drm_property_blob *solid_fill = drm_property_lookup_blob(dev, val);
> +
> +		ret = drm_atomic_set_solid_fill_prop(state, solid_fill);
> +		drm_property_blob_put(solid_fill);
> +
> +		return ret;

Bonus point: dropping version from SOLID_FILL would allow us to use 
drm_atomic_replace_property_blob_from_id() here.

>   	} else if (property == plane->alpha_property) {
>   		state->alpha = val;
>   	} else if (property == plane->blend_mode_property) {
> @@ -620,6 +672,9 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
>   		*val = state->src_h;
>   	} else if (property == plane->pixel_source_property) {
>   		*val = state->pixel_source;
> +	} else if (property == plane->solid_fill_property) {
> +		*val = state->solid_fill_blob ?
> +			state->solid_fill_blob->base.id : 0;
>   	} else if (property == plane->alpha_property) {
>   		*val = state->alpha;
>   	} else if (property == plane->blend_mode_property) {
> diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
> index c500310a3d09..c632dfcd8a9b 100644
> --- a/drivers/gpu/drm/drm_blend.c
> +++ b/drivers/gpu/drm/drm_blend.c
> @@ -200,6 +200,10 @@
>    *	"FB":
>    *		Framebuffer source set by the "FB_ID" property.
>    *
> + * solid_fill:
> + *	solid_fill is set up with drm_plane_create_solid_fill_property(). It
> + *	contains pixel data that drivers can use to fill a plane.
> + *
>    * Note that all the property extensions described here apply either to the
>    * plane or the CRTC (e.g. for the background color, which currently is not
>    * exposed and assumed to be black).
> @@ -700,3 +704,29 @@ int drm_plane_create_pixel_source_property(struct drm_plane *plane,
>   	return 0;
>   }
>   EXPORT_SYMBOL(drm_plane_create_pixel_source_property);
> +
> +/**
> + * drm_plane_create_solid_fill_property - create a new solid_fill property
> + * @plane: drm plane
> + *
> + * This creates a new property blob that holds pixel data for solid fill planes.
> + * The property is exposed to userspace as a property blob called "solid_fill".
> + *
> + * For information on what the blob contains, see `drm_mode_solid_fill`.
> + */
> +int drm_plane_create_solid_fill_property(struct drm_plane *plane)
> +{
> +	struct drm_property *prop;
> +
> +	prop = drm_property_create(plane->dev,
> +			DRM_MODE_PROP_ATOMIC | DRM_MODE_PROP_BLOB,
> +			"solid_fill", 0);
> +	if (!prop)
> +		return -ENOMEM;
> +
> +	drm_object_attach_property(&plane->base, prop, 0);
> +	plane->solid_fill_property = prop;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_plane_create_solid_fill_property);
> diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h
> index 122bbfbaae33..e7158fbee389 100644
> --- a/include/drm/drm_blend.h
> +++ b/include/drm/drm_blend.h
> @@ -60,4 +60,5 @@ int drm_plane_create_blend_mode_property(struct drm_plane *plane,
>   					 unsigned int supported_modes);
>   int drm_plane_create_pixel_source_property(struct drm_plane *plane,
>   					   unsigned long extra_sources);
> +int drm_plane_create_solid_fill_property(struct drm_plane *plane);
>   #endif
> diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
> index 89508b4dea4a..abf1458fa099 100644
> --- a/include/drm/drm_plane.h
> +++ b/include/drm/drm_plane.h
> @@ -46,6 +46,17 @@ enum drm_plane_pixel_source {
>   	DRM_PLANE_PIXEL_SOURCE_MAX
>   };
>   
> +/**
> + * struct solid_fill_property - RGB values for solid fill plane
> + *
> + * Note: This is the V1 for this feature
> + */
> +struct drm_solid_fill {
> +	uint32_t r;
> +	uint32_t g;
> +	uint32_t b;
> +};
> +
>   /**
>    * struct drm_plane_state - mutable plane state
>    *
> @@ -130,6 +141,23 @@ struct drm_plane_state {
>   	 */
>   	enum drm_plane_pixel_source pixel_source;
>   
> +	/**
> +	 * @solid_fill_blob:
> +	 *
> +	 * Blob containing relevant information for a solid fill plane
> +	 * including pixel format and data. See
> +	 * drm_plane_create_solid_fill_property() for more details.
> +	 */
> +	struct drm_property_blob *solid_fill_blob;
> +
> +	/**
> +	 * @solid_fill:
> +	 *
> +	 * Pixel data for solid fill planes. See
> +	 * drm_plane_create_solid_fill_property() for more details.
> +	 */
> +	struct drm_solid_fill solid_fill;
> +
>   	/**
>   	 * @alpha:
>   	 * Opacity of the plane with 0 as completely transparent and 0xffff as
> @@ -720,6 +748,13 @@ struct drm_plane {
>   	 */
>   	struct drm_property *pixel_source_property;
>   
> +	/**
> +	 * @solid_fill_property:
> +	 * Optional solid_fill property for this plane. See
> +	 * drm_plane_create_solid_fill_property().
> +	 */
> +	struct drm_property *solid_fill_property;
> +
>   	/**
>   	 * @alpha_property:
>   	 * Optional alpha property for this plane. See
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 43691058d28f..53c8efa5ad7f 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -259,6 +259,30 @@ struct drm_mode_modeinfo {
>   	char name[DRM_DISPLAY_MODE_LEN];
>   };
>   
> +/**
> + * struct drm_mode_solid_fill - User info for solid fill planes
> + *
> + * This is the userspace API solid fill information structure.
> + *
> + * Userspace can enable solid fill planes by assigning the plane "solid_fill"
> + * property to a blob containing a single drm_mode_solid_fill struct populated with an RGB323232
> + * color and setting the pixel source to "SOLID_FILL".
> + *
> + * For information on the plane property, see drm_plane_create_solid_fill_property()
> + *
> + * @version: Version of the blob. Currently, there is only support for version == 1
> + * @r: Red color value of single pixel
> + * @g: Green color value of single pixel
> + * @b: Blue color value of single pixel
> + */
> +struct drm_mode_solid_fill {
> +	__u32 version;
> +	__u32 r;
> +	__u32 g;
> +	__u32 b;
> +};
> +
> +
>   struct drm_mode_card_res {
>   	__u64 fb_id_ptr;
>   	__u64 crtc_id_ptr;
> 

-- 
With best wishes
Dmitry

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