Re: [PATCH v3 20/33] drm/vkms: Introduce config for plane zpos property

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> VKMS can render plane in any order. Introduce the appropriate
> configuration.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>

> @@ -253,6 +256,33 @@ bool vkms_config_valid_plane_color_range(const struct vkms_config *config,
>  }
>  EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_color_range);
>
> +VISIBLE_IF_KUNIT
> +bool vkms_config_valid_plane_zpos(const struct vkms_config *config,
> +				  const struct vkms_config_plane *plane_cfg)
> +{
> +	struct drm_device *dev = config->dev ? &config->dev->drm : NULL;
> +
> +	if (!vkms_config_plane_get_zpos_enabled(plane_cfg) ||
> +	    !vkms_config_plane_get_zpos_mutable(plane_cfg))
> +		return true;
> +
> +	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) ||
> +	    vkms_config_plane_get_zpos_initial(plane_cfg) <
> +	    vkms_config_plane_get_zpos_min(plane_cfg)) {
> +		drm_info(dev, "Configured zpos value outside (zpos min; zpos max)\n");
> +		return false;
> +	}

Weird grouping. It should rather be:

 if (max < min) {...}

 if (initial > max || initial < min) {...}

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com