Re: [PATCH 12/22] drm/vkms: Introduce config for plane zpos property

["José Expósito" <jose.exposito89@gmail.com>]

On Sat, Oct 18, 2025 at 04:01:12AM +0200, Louis Chauvet wrote:
> VKMS can render plane in any order. Introduce the appropriate
> configuration.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  drivers/gpu/drm/vkms/tests/vkms_config_test.c |   3 +
>  drivers/gpu/drm/vkms/vkms_config.c            |  21 ++++
>  drivers/gpu/drm/vkms/vkms_config.h            | 142 ++++++++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_plane.c             |  11 ++
>  4 files changed, 177 insertions(+)
> 
> diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
> index d75a6252e4d2..f2b38b436252 100644
> --- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
> +++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
> @@ -172,6 +172,9 @@ static void vkms_config_test_default_config(struct kunit *test)
>  			n_possible_crtcs++;
>  		}
>  		KUNIT_EXPECT_EQ(test, n_possible_crtcs, 1);
> +		KUNIT_EXPECT_EQ(test, vkms_config_plane_get_zpos_enabled(plane_cfg), false);
> +		// No need to test the other zpos configurations as they are discarded if
> +		// the zpos property is not created.
>  	}
>  
>  	/* Encoders */
> diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
> index 0b975a0d47aa..5da34a3e8114 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.c
> +++ b/drivers/gpu/drm/vkms/vkms_config.c
> @@ -86,6 +86,7 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
>  	if (IS_ERR(plane_cfg))
>  		goto err_alloc;
>  	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_PRIMARY);
> +	vkms_config_plane_set_zpos_enabled(plane_cfg, false);
>  
>  	crtc_cfg = vkms_config_create_crtc(config);
>  	if (IS_ERR(crtc_cfg))
> @@ -103,6 +104,7 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
>  
>  			vkms_config_plane_set_type(plane_cfg,
>  						   DRM_PLANE_TYPE_OVERLAY);
> +			vkms_config_plane_set_zpos_enabled(plane_cfg, false);
>  
>  			if (vkms_config_plane_attach_crtc(plane_cfg, crtc_cfg))
>  				goto err_alloc;
> @@ -115,6 +117,7 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
>  			goto err_alloc;
>  
>  		vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_CURSOR);
> +		vkms_config_plane_set_zpos_enabled(plane_cfg, false);
>  
>  		if (vkms_config_plane_attach_crtc(plane_cfg, crtc_cfg))
>  			goto err_alloc;
> @@ -206,6 +209,24 @@ static bool valid_plane_properties(const struct vkms_config *config)
>  			drm_info(dev, "Configured default color range is not supported by the plane\n");
>  			return false;
>  		}
> +		if (vkms_config_plane_get_zpos_initial(plane_cfg) >
> +		    vkms_config_plane_get_zpos_max(plane_cfg)) {
> +			drm_info(dev, "Configured initial zpos value bigger than zpos max\n");
> +			return false;
> +		}
> +
> +		if (vkms_config_plane_get_zpos_max(plane_cfg) <
> +		    vkms_config_plane_get_zpos_min(plane_cfg)) {
> +			drm_info(dev, "Configured zpos max value smaller than zpos min\n");
> +			return false;
> +		}
> +
> +		if (vkms_config_plane_get_zpos_initial(plane_cfg) <
> +		    vkms_config_plane_get_zpos_min(plane_cfg)) {
> +			drm_info(dev, "Configured initial zpos value smaller than zpos min\n");
> +			return false;
> +		}
> +

Like I suggested with other validations, it'd be nice to extract this to a
helper to simplify testing.

Also, these properties are not listed in vkms_config_show().

>  	}
>  	return true;
>  }
> diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
> index 0b7067508e5f..267e45f5a617 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.h
> +++ b/drivers/gpu/drm/vkms/vkms_config.h
> @@ -49,6 +49,11 @@ struct vkms_config {
>   * @supported_color_encoding: Color encoding that this plane will support
>   * @default_color_range: Default color range that should be used by this plane
>   * @supported_color_range: Color range that this plane will support
> + * @zpos_enable: Enable or disable the zpos property

@zpos_enabled

> + * @zpos_mutable: Make the zpos property mutable or not (ignored if @zpos_enable is false)
> + * @zpos_initial: Initial value for zpos property (ignored if @zpos_enable is false)
> + * @zpos_min: Minimal value for zpos property (ignored if @zpos_enable is false)
> + * @zpos_max: Maximal value for zpos property (ignored if @zpos_enable is false)

For these 4 as well: "(ignored if @zpos_enabled...".

>   */
>  struct vkms_config_plane {
>  	struct list_head link;
> @@ -65,6 +70,11 @@ struct vkms_config_plane {
>  	u32 *supported_formats;
>  	unsigned int supported_formats_count;
>  	struct xarray possible_crtcs;
> +	bool zpos_enabled;
> +	bool zpos_mutable;
> +	unsigned int zpos_initial;
> +	unsigned int zpos_min;
> +	unsigned int zpos_max;
>  
>  	/* Internal usage */
>  	struct vkms_plane *plane;
> @@ -477,6 +487,138 @@ vkms_config_plane_get_name(struct vkms_config_plane *plane_cfg)
>  	return plane_cfg->name;
>  }
>  
> +/**
> + * vkms_config_plane_set_zpos_enabled() - Enable or disable zpos property for a plane
> + * @plane_cfg: Plane configuration to modify
> + * @zpos_enabled: Whether to enable the zpos property
> + */
> +static inline
> +void vkms_config_plane_set_zpos_enabled(struct vkms_config_plane *plane_cfg,
> +					bool zpos_enabled)
> +{
> +	plane_cfg->zpos_enabled = zpos_enabled;
> +}
> +
> +/**
> + * vkms_config_plane_set_zpos_mutable() - Set whether zpos property is mutable
> + * @plane_cfg: Plane configuration to modify
> + * @zpos_mutable: Whether the zpos property should be mutable
> + */
> +static inline
> +void vkms_config_plane_set_zpos_mutable(struct vkms_config_plane *plane_cfg,
> +					bool zpos_mutable)
> +{
> +	plane_cfg->zpos_mutable = zpos_mutable;
> +}
> +
> +/**
> + * vkms_config_plane_set_zpos_initial() - Set the initial zpos value
> + * @plane_cfg: Plane configuration to modify
> + * @zpos_initial: Initial zpos value
> + */
> +static inline
> +void vkms_config_plane_set_zpos_initial(struct vkms_config_plane *plane_cfg,
> +					unsigned int zpos_initial)
> +{
> +	plane_cfg->zpos_initial = zpos_initial;
> +}
> +
> +/**
> + * vkms_config_plane_set_zpos_min() - Set the minimum zpos value
> + * @plane_cfg: Plane configuration to modify
> + * @zpos_min: Minimum zpos value
> + */
> +static inline
> +void vkms_config_plane_set_zpos_min(struct vkms_config_plane *plane_cfg,
> +				    unsigned int zpos_min)
> +{
> +	plane_cfg->zpos_min = zpos_min;
> +}
> +
> +/**
> + * vkms_config_plane_set_zpos_max() - Set the maximum zpos value
> + * @plane_cfg: Plane configuration to modify
> + * @zpos_max: Maximum zpos value
> + *
> + * Sets the maximum allowed value for the zpos property. This setting is
> + * ignored if zpos is disabled.
> + */
> +static inline
> +void vkms_config_plane_set_zpos_max(struct vkms_config_plane *plane_cfg,
> +				    unsigned int zpos_max)
> +{
> +	plane_cfg->zpos_max = zpos_max;
> +}
> +
> +/**
> + * vkms_config_plane_get_zpos_enabled() - Check if zpos property is enabled
> + * @plane_cfg: Plane configuration to check
> + *
> + * Returns:
> + * True if the zpos property is enabled for this plane, false otherwise.
> + */
> +static inline
> +bool vkms_config_plane_get_zpos_enabled(struct vkms_config_plane *plane_cfg)
> +{
> +	return plane_cfg->zpos_enabled;
> +}
> +
> +/**
> + * vkms_config_plane_get_zpos_mutable() - Check if zpos property is mutable
> + * @plane_cfg: Plane configuration to check
> + *
> + * Returns:
> + * True if the zpos property is mutable for this plane, false otherwise.
> + * Returns false if zpos is disabled.
> + */
> +static inline
> +bool vkms_config_plane_get_zpos_mutable(struct vkms_config_plane *plane_cfg)
> +{
> +	return plane_cfg->zpos_mutable;
> +}
> +
> +/**
> + * vkms_config_plane_get_zpos_initial() - Get the initial zpos value
> + * @plane_cfg: Plane configuration to check
> + *
> + * Returns:
> + * The initial zpos value for this plane. The return value is undefined if
> + * zpos is disabled.
> + */
> +static inline
> +unsigned int vkms_config_plane_get_zpos_initial(struct vkms_config_plane *plane_cfg)
> +{
> +	return plane_cfg->zpos_initial;
> +}
> +
> +/**
> + * vkms_config_plane_get_zpos_min() - Get the minimum zpos value
> + * @plane_cfg: Plane configuration to check
> + *
> + * Returns:
> + * The minimum allowed zpos value for this plane. The return value is undefined
> + * if zpos is disabled.
> + */
> +static inline
> +unsigned int vkms_config_plane_get_zpos_min(struct vkms_config_plane *plane_cfg)
> +{
> +	return plane_cfg->zpos_min;
> +}
> +
> +/**
> + * vkms_config_plane_get_zpos_max() - Get the maximum zpos value
> + * @plane_cfg: Plane configuration to check
> + *
> + * Returns:
> + * The maximum allowed zpos value for this plane. The return value is undefined
> + * if zpos is disabled.
> + */
> +static inline
> +unsigned int vkms_config_plane_get_zpos_max(struct vkms_config_plane *plane_cfg)
> +{
> +	return plane_cfg->zpos_max;
> +}
> +
>  /**
>   * vkms_config_plane_attach_crtc - Attach a plane to a CRTC
>   * @plane_cfg: Plane to attach
> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> index 0414865915d8..51f6372a6f72 100644
> --- a/drivers/gpu/drm/vkms/vkms_plane.c
> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> @@ -209,5 +209,16 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
>  					  vkms_config_plane_get_default_color_encoding(config),
>  					  vkms_config_plane_get_default_color_range(config));
>  
> +	if (vkms_config_plane_get_zpos_enabled(config)) {
> +		if (vkms_config_plane_get_zpos_mutable(config))
> +			drm_plane_create_zpos_property(&plane->base,
> +						       vkms_config_plane_get_zpos_initial(config),
> +						       vkms_config_plane_get_zpos_min(config),
> +						       vkms_config_plane_get_zpos_max(config));
> +		else
> +			drm_plane_create_zpos_immutable_property(&plane->base,
> +								 vkms_config_plane_get_zpos_initial(config));
> +	}
> +
>  	return plane;
>  }
> 
> -- 
> 2.51.0
>