[libcamera-devel] [PATCH 12/13] libcamera: pipeline: simple: Don't disable links carrying other streams

[Jacopo Mondi]

Hi Laurent,

On Mon, Aug 01, 2022 at 03:05:42AM +0300, Laurent Pinchart via libcamera-devel wrote:
> From: Phi-Bang Nguyen <pnguyen at baylibre.com>
>
> If a subdev supports the internal routing API, pads unrelated to the
> pipeline for a given camera sensor may carry streams for other cameras.
> The link setup logic is updated to take this into account, by avoiding
> disabling links to unrelated pads.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/libcamera/pipeline/simple/simple.cpp | 28 +++++++++++++++++++++---
>  1 file changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> index 2a8811183907..c80e462bc449 100644
> --- a/src/libcamera/pipeline/simple/simple.cpp
> +++ b/src/libcamera/pipeline/simple/simple.cpp
> @@ -221,6 +221,11 @@ public:
>  	struct Entity {
>  		/* The media entity, always valid. */
>  		MediaEntity *entity;
> +		/*
> +		 * Whether or not the entity is a subdev that supports the
> +		 * routing API.
> +		 */
> +		bool supportsRouting;
>  		/*
>  		 * The local sink pad connected to the upstream entity, null for
>  		 * the camera sensor at the beginning of the pipeline.
> @@ -404,9 +409,13 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,
>  		 */
>
>  		std::vector<const MediaPad *> pads;
> +		bool supportsRouting = false;
>
> -		if (sinkPad)
> +		if (sinkPad) {
>  			pads = routedSourcePads(sinkPad);
> +			if (!pads.empty())
> +				supportsRouting = true;
> +		}
>
>  		if (pads.empty()) {
>  			for (const MediaPad *pad : entity->pads()) {
> @@ -421,7 +430,9 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,
>  				MediaEntity *next = link->sink()->entity();
>  				if (visited.find(next) == visited.end()) {
>  					queue.push({ next, link->sink() });
> -					parents.insert({ next, { entity, sinkPad, pad, link } });
> +
> +					Entity e{ entity, supportsRouting, sinkPad, pad, link };
> +					parents.insert({ next, e });
>  				}
>  			}
>  		}
> @@ -435,7 +446,7 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,
>  	 * to the sensor. Store all the entities in the pipeline, from the
>  	 * camera sensor to the video node, in entities_.
>  	 */
> -	entities_.push_front({ entity, sinkPad, nullptr, nullptr });
> +	entities_.push_front({ entity, false, sinkPad, nullptr, nullptr });
>
>  	for (auto it = parents.find(entity); it != parents.end();
>  	     it = parents.find(entity)) {
> @@ -617,6 +628,17 @@ int SimpleCameraData::setupLinks()

I would also update the comment at function begin that reports

	/*
	 * Configure all links along the pipeline. Some entities may not allow
	 * multiple sink links to be enabled together, even on different sink
	 * pads. We must thus start by disabling all sink links (but the one we
	 * want to enable) before enabling the pipeline link.
	 */

To mention that this doesn't apply to routed subdevs

>  		}
>
>  		for (MediaPad *pad : e.entity->pads()) {
> +			/*
> +			 * If the entity supports the V4L2 internal routing API,
> +			 * assume that it may carry multiple independent streams
> +			 * concurrently, and only disable links on the sink and
> +			 * source pads used by the pipeline.
> +			 */
> +			if (e.supportsRouting) {
> +				if (pad != e.sink && pad != e.source)

Or
                        if (e.supportsRouting &&
                            (pad != e.sink && pad != e.source))

> +					continue;
> +			}
> +
>  			for (MediaLink *link : pad->links()) {
>  				if (link == sinkLink)
>  					continue;
> --
> Regards,
>
> Laurent Pinchart
>