Re: [PATCH v6 2/3] drm/plane: modify create_in_formats to accommodate async

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Feb 19, 2025 at 02:47:24PM +0530, Arun R Murthy wrote:
> create_in_formats creates the list of supported format/modifiers for
> synchronous flips, modify the same function so as to take the
> format_mod_supported as argument and create list of format/modifier for
> async as well.
> 
> v5: create_in_formats can return -ve value in failure case, correct the
> if condition to check the creation of blob <Chaitanya>
> Dont add the modifier for which none of the formats is not supported.
> v6: Remove the code for masking the unsupported modifiers as UMD can
> leave with it. (Naveen/Chaitanya)
> 
> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> Tested-by: Naveen Kumar <naveen1.kumar@intel.com>
> ---
>  drivers/gpu/drm/drm_plane.c | 45 +++++++++++++++++++++++++++++++++------------
>  1 file changed, 33 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> index fe181c1002171acc68d3054c2d178f9b9f501fe2..fc26ef8a6cab346c9491495b57f88f1eb205d22c 100644
> --- a/drivers/gpu/drm/drm_plane.c
> +++ b/drivers/gpu/drm/drm_plane.c
> @@ -193,9 +193,12 @@ modifiers_ptr(struct drm_format_modifier_blob *blob)
>  	return (struct drm_format_modifier *)(((char *)blob) + blob->modifiers_offset);
>  }
>  
> -static int create_in_format_blob(struct drm_device *dev, struct drm_plane *plane)
> +static int create_in_format_blob(struct drm_device *dev, struct drm_plane *plane,
> +				 bool (*format_mod_supported)
> +						(struct drm_plane *plane,
> +						 uint32_t format,
> +						 uint64_t modifier))
>  {
> -	const struct drm_mode_config *config = &dev->mode_config;
>  	struct drm_property_blob *blob;
>  	struct drm_format_modifier *mod;
>  	size_t blob_size, formats_size, modifiers_size;
> @@ -237,13 +240,17 @@ static int create_in_format_blob(struct drm_device *dev, struct drm_plane *plane
>  	mod = modifiers_ptr(blob_data);
>  	for (i = 0; i < plane->modifier_count; i++) {
>  		for (j = 0; j < plane->format_count; j++) {
> -			if (!plane->funcs->format_mod_supported ||
> -			    plane->funcs->format_mod_supported(plane,
> -							       plane->format_types[j],
> -							       plane->modifiers[i])) {
> +			if (!format_mod_supported || format_mod_supported
> +							(plane,
> +							 plane->format_types[j],
> +							 plane->modifiers[i])) {

Weird line breaks.

>  				mod->formats |= 1ULL << j;
>  			}
>  		}
> +		if (!mod->formats) {
> +			blob_data->count_modifiers--;
> +			continue;
> +		}

I hope no userspace rejects the blob if there
is extra data at the end...

Since this can actually change the behaviour 
I think this one needs to be a separate patch
in case we need a revert later.

>  
>  		mod->modifier = plane->modifiers[i];
>  		mod->offset = 0;
> @@ -251,10 +258,7 @@ static int create_in_format_blob(struct drm_device *dev, struct drm_plane *plane
>  		mod++;
>  	}
>  
> -	drm_object_attach_property(&plane->base, config->modifiers_property,
> -				   blob->base.id);
> -
> -	return 0;
> +	return blob->base.id;

The return type is wrong for this.

I think it'd probably be better to return
struct drm_property_blob* instead so we can
return errors properly as well.

>  }
>  
>  /**
> @@ -371,6 +375,7 @@ static int __drm_universal_plane_init(struct drm_device *dev,
>  	};
>  	unsigned int format_modifier_count = 0;
>  	int ret;
> +	int blob_id;
>  
>  	/* plane index is used with 32bit bitmasks */
>  	if (WARN_ON(config->num_total_plane >= 32))
> @@ -477,8 +482,24 @@ static int __drm_universal_plane_init(struct drm_device *dev,
>  		drm_plane_create_hotspot_properties(plane);
>  	}
>  
> -	if (format_modifier_count)
> -		create_in_format_blob(dev, plane);
> +	if (format_modifier_count) {
> +		blob_id = create_in_format_blob(dev, plane,
> +						plane->funcs->format_mod_supported);
> +		if (blob_id > 0)
> +			drm_object_attach_property(&plane->base,
> +						   config->modifiers_property,
> +						   blob_id);
> +	}
> +
> +	if (plane->funcs->format_mod_supported_async) {
> +		blob_id = create_in_format_blob(dev, plane,
> +						plane->funcs->format_mod_supported_async);
> +		if (blob_id > 0)
> +			drm_object_attach_property(&plane->base,
> +						   config->async_modifiers_property,
> +						   blob_id);
> +	}
> +
>  
>  	return 0;
>  }
> 
> -- 
> 2.25.1

-- 
Ville Syrjälä
Intel