[libcamera-devel] [PATCH v5 3/9] libcamera: media_device: Handle ancillary links in populateLinks()

[Jean-Michel Hautbois]

Hi !

Thanks for the patch !

On 04/03/2022 00:49, Daniel Scally wrote:
> The populateLinks() function can't currently handle ancillary links
> which causes an error to be thrown in process() when the MediaObject
> cannot be cast to a MediaPad.
> 
> Add explicit handling for the different link types, creating either
> pad-2-pad links or else storing the pointer to the ancillary device
> MediaEntity in the ancillaryEntities_ member of the primary.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Daniel Scally <djrscally at gmail.com>

Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>

> ---
> Changes in v5:
> 	- Fix some formatting and comments (Laurent)
> 
> Changes in v4:
> 
> 	- Added some error checking to confirm that the casts to pad or entity
> 	return valid pointers (Laurent)
> 
> Changes in v3:
> 
> 	- Split out the new macro
> 	- Fixed some style errors and comments
> 	- Added a default case
> 
>   src/libcamera/media_device.cpp | 64 +++++++++++++++++++++++++---------
>   1 file changed, 48 insertions(+), 16 deletions(-)
> 
> diff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp
> index 941f86c2..7c94da9e 100644
> --- a/src/libcamera/media_device.cpp
> +++ b/src/libcamera/media_device.cpp
> @@ -683,40 +683,72 @@ bool MediaDevice::populateLinks(const struct media_v2_topology &topology)
>   					   (topology.ptr_links);
>   
>   	for (unsigned int i = 0; i < topology.num_links; ++i) {
> -		/* We only care about pad-2-pad links here. */
> -		if ((mediaLinks[i].flags & MEDIA_LNK_FL_LINK_TYPE) !=
> -		    MEDIA_LNK_FL_DATA_LINK)
> +		if ((mediaLinks[i].flags & MEDIA_LNK_FL_LINK_TYPE) ==
> +		    MEDIA_LNK_FL_INTERFACE_LINK)
>   			continue;
>   
> -		/* Store references to source and sink pads in the link. */
> +		/* Look up the source and sink objects. */
>   		unsigned int source_id = mediaLinks[i].source_id;
> -		MediaPad *source = dynamic_cast<MediaPad *>
> -				   (object(source_id));
> +		MediaObject *source = object(source_id);
>   		if (!source) {
>   			LOG(MediaDevice, Error)
> -				<< "Failed to find pad with id: "
> +				<< "Failed to find MediaObject with id "
>   				<< source_id;
>   			return false;
>   		}
>   
>   		unsigned int sink_id = mediaLinks[i].sink_id;
> -		MediaPad *sink = dynamic_cast<MediaPad *>
> -				 (object(sink_id));
> +		MediaObject *sink = object(sink_id);
>   		if (!sink) {
>   			LOG(MediaDevice, Error)
> -				<< "Failed to find pad with id: "
> +				<< "Failed to find MediaObject with id "
>   				<< sink_id;
>   			return false;
>   		}
>   
> -		MediaLink *link = new MediaLink(&mediaLinks[i], source, sink);
> -		if (!addObject(link)) {
> -			delete link;
> -			return false;
> +		switch (mediaLinks[i].flags & MEDIA_LNK_FL_LINK_TYPE) {
> +		case MEDIA_LNK_FL_DATA_LINK: {
> +			MediaPad *sourcePad = dynamic_cast<MediaPad *>(source);
> +			MediaPad *sinkPad = dynamic_cast<MediaPad *>(sink);
> +			if (!source || !sink) {
> +				LOG(MediaDevice, Error)
> +					<< "Source or sink is not a pad";
> +				return false;
> +			}
> +
> +			MediaLink *link = new MediaLink(&mediaLinks[i],
> +							sourcePad, sinkPad);
> +			if (!addObject(link)) {
> +				delete link;
> +				return false;
> +			}
> +
> +			link->source()->addLink(link);
> +			link->sink()->addLink(link);
> +
> +			break;
>   		}
>   
> -		source->addLink(link);
> -		sink->addLink(link);
> +		case MEDIA_LNK_FL_ANCILLARY_LINK: {
> +			MediaEntity *primary = dynamic_cast<MediaEntity *>(source);
> +			MediaEntity *ancillary = dynamic_cast<MediaEntity *>(sink);
> +			if (!primary || !ancillary) {
> +				LOG(MediaDevice, Error)
> +					<< "Source or sink is not an entity";
> +				return false;
> +			}
> +
> +			primary->addAncillaryEntity(ancillary);
> +
> +			break;
> +		}
> +
> +		default:
> +			LOG(MediaDevice, Warning)
> +				<< "Unknown media link type";
> +
> +			break;
> +		}
>   	}
>   
>   	return true;