[PATCH v5 2/5] pipeline: simple: Use proper device for frame start events

[Stanislaw Gruszka]

Currently we use frame start event from video capture device to
apply controls. But the capture device might not generate the events.
Usually CSI-2 receiver is proper device to subscribe for start
frame events.

To fix, loop over devices in the pipeline to find the one that
supports events and use it as start frame emitter.

Co-developed-by: Hans de Goede <hdegoede at redhat.com>
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka at linux.intel.com>
---
 src/libcamera/pipeline/simple/simple.cpp | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index 6e039bf3..063a098f 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -277,6 +277,7 @@ public:
 	std::list<Entity> entities_;
 	std::unique_ptr<CameraSensor> sensor_;
 	V4L2VideoDevice *video_;
+	V4L2Subdevice *frameStartEmitter_;
 
 	std::vector<Configuration> configs_;
 	std::map<PixelFormat, std::vector<const Configuration *>> formats_;
@@ -579,6 +580,19 @@ int SimpleCameraData::init()
 
 	properties_ = sensor_->properties();
 
+	frameStartEmitter_ = nullptr;
+	for (const Entity &entity : entities_) {
+		V4L2Subdevice *sd = pipe->subdev(entity.entity);
+		if (!sd || !sd->supportsFrameStartEvent())
+			continue;
+
+		LOG(SimplePipeline, Debug)
+			<< "Using " << entity.entity->name() << " frameStart signal";
+
+		frameStartEmitter_ = sd;
+		break;
+	}
+
 	return 0;
 }
 
@@ -1215,6 +1229,7 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
 		static_cast<SimpleCameraConfiguration *>(c);
 	SimpleCameraData *data = cameraData(camera);
 	V4L2VideoDevice *video = data->video_;
+	V4L2Subdevice *frameStartEmitter = data->frameStartEmitter_;
 	int ret;
 
 	/*
@@ -1285,8 +1300,9 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
 	data->delayedCtrls_ =
 		std::make_unique<DelayedControls>(data->sensor_->device(),
 						  params);
-	data->video_->frameStart.connect(data->delayedCtrls_.get(),
-					 &DelayedControls::applyControls);
+	if (frameStartEmitter)
+		frameStartEmitter->frameStart.connect(data->delayedCtrls_.get(),
+						      &DelayedControls::applyControls);
 
 	StreamConfiguration inputCfg;
 	inputCfg.pixelFormat = pipeConfig->captureFormat;
-- 
2.43.0