[libcamera-devel] [PATCH v2 1/2] pipeline: ipu3: Store requests in the case a buffer shortage

[Hirokazu Honda]

PipelineHandlerIPU3 returns -ENOBUFS and -ENOMEM on queueing a
request when there are not sufficient buffers for the request.
Since the request will be successful if it is queued later when
enough buffers are available. The requests failed due to a buffer
shortage should be stored and retried later in the FIFO order.
This introduces the queue in IPU3CameraData to do that.

Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
---
 src/libcamera/pipeline/ipu3/ipu3.cpp | 58 ++++++++++++++++++----------
 1 file changed, 37 insertions(+), 21 deletions(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 519cad4f..c73e4f7c 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -66,6 +66,7 @@ public:
 	void cio2BufferReady(FrameBuffer *buffer);
 	void paramBufferReady(FrameBuffer *buffer);
 	void statBufferReady(FrameBuffer *buffer);
+	int queuePendingRequests();
 
 	CIO2Device cio2_;
 	ImgUDevice *imgu_;
@@ -84,6 +85,7 @@ public:
 
 	std::unique_ptr<ipa::ipu3::IPAProxyIPU3> ipa_;
 
+	std::queue<Request *> pendingRequests_;
 private:
 	void queueFrameAction(unsigned int id,
 			      const ipa::ipu3::IPU3Action &action);
@@ -764,6 +766,8 @@ void PipelineHandlerIPU3::stop(Camera *camera)
 	IPU3CameraData *data = cameraData(camera);
 	int ret = 0;
 
+	data->pendingRequests_ = {};
+
 	data->ipa_->stop();
 
 	ret |= data->imgu_->stop();
@@ -774,36 +778,48 @@ void PipelineHandlerIPU3::stop(Camera *camera)
 	freeBuffers(camera);
 }
 
-int PipelineHandlerIPU3::queueRequestDevice(Camera *camera, Request *request)
+int IPU3CameraData::queuePendingRequests()
 {
-	IPU3CameraData *data = cameraData(camera);
+	while (!pendingRequests_.empty()) {
+		Request *request = pendingRequests_.front();
 
-	IPU3Frames::Info *info = data->frameInfos_.create(request);
-	if (!info)
-		return -ENOBUFS;
+		IPU3Frames::Info *info = frameInfos_.create(request);
+		if (!info)
+			break;
 
-	/*
-	 * Queue a buffer on the CIO2, using the raw stream buffer provided in
-	 * the request, if any, or a CIO2 internal buffer otherwise.
-	 */
-	FrameBuffer *reqRawBuffer = request->findBuffer(&data->rawStream_);
-	FrameBuffer *rawBuffer = data->cio2_.queueBuffer(request, reqRawBuffer);
-	if (!rawBuffer) {
-		data->frameInfos_.remove(info);
-		return -ENOMEM;
-	}
+		/*
+		 * Queue a buffer on the CIO2, using the raw stream buffer
+		 * provided in the request, if any, or a CIO2 internal buffer
+		 * otherwise.
+		 */
+		FrameBuffer *reqRawBuffer = request->findBuffer(&rawStream_);
+		FrameBuffer *rawBuffer = cio2_.queueBuffer(request, reqRawBuffer);
+		if (!rawBuffer) {
+			frameInfos_.remove(info);
+			break;
+		}
 
-	info->rawBuffer = rawBuffer;
+		info->rawBuffer = rawBuffer;
 
-	ipa::ipu3::IPU3Event ev;
-	ev.op = ipa::ipu3::EventProcessControls;
-	ev.frame = info->id;
-	ev.controls = request->controls();
-	data->ipa_->processEvent(ev);
+		ipa::ipu3::IPU3Event ev;
+		ev.op = ipa::ipu3::EventProcessControls;
+		ev.frame = info->id;
+		ev.controls = request->controls();
+		ipa_->processEvent(ev);
+
+		pendingRequests_.pop();
+	}
 
 	return 0;
 }
 
+int PipelineHandlerIPU3::queueRequestDevice(Camera *camera, Request *request)
+{
+	IPU3CameraData *data = cameraData(camera);
+	data->pendingRequests_.emplace(request);
+	return data->queuePendingRequests();
+}
+
 bool PipelineHandlerIPU3::match(DeviceEnumerator *enumerator)
 {
 	int ret;
-- 
2.31.0.208.g409f899ff0-goog