[libcamera-devel] [PATCH v3 21/33] libcamera: pipeline: rkisp1: Destroy frame information before completing request

[Niklas Söderlund]

It's common for applications to create and queue a new request in a
previous request completion handler. When the new request gets queued to
the RkISP1 pipeline handler it tries to find a parameters and statistic
buffer to be used with the request. The problem is if the pipeline depth
is already filled there are no internal buffers free to be used by the
new request.

This was solved by allocation one more parameters and statistic buffer
then the pipeline depth, this is waste full. Instead free the request
that is about to be completed resources before it is signaled to the
application, this way if the pipeline depth is full it can reuse the
internal resources and the waste full allocation can be removed.

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
---
* Changes since v2
- Rewrote commit message.
- Actually remove the wasteful allocation of extra buffers in this
  commit instead of depending on the switch to FrameBuffer to do it for
  us.
---
 src/libcamera/pipeline/rkisp1/rkisp1.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
index 979b670e4cb75512..607ff85539a22324 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
@@ -671,14 +671,14 @@ int PipelineHandlerRkISP1::allocateBuffers(Camera *camera,
 	if (ret)
 		return ret;
 
-	paramPool_.createBuffers(stream->configuration().bufferCount + 1);
+	paramPool_.createBuffers(stream->configuration().bufferCount);
 	ret = param_->exportBuffers(&paramPool_);
 	if (ret) {
 		video_->releaseBuffers();
 		return ret;
 	}
 
-	statPool_.createBuffers(stream->configuration().bufferCount + 1);
+	statPool_.createBuffers(stream->configuration().bufferCount);
 	ret = stat_->exportBuffers(&statPool_);
 	if (ret) {
 		param_->releaseBuffers();
@@ -686,13 +686,13 @@ int PipelineHandlerRkISP1::allocateBuffers(Camera *camera,
 		return ret;
 	}
 
-	for (unsigned int i = 0; i < stream->configuration().bufferCount + 1; i++) {
+	for (unsigned int i = 0; i < stream->configuration().bufferCount; i++) {
 		data->ipaBuffers_.push_back({ .id = RKISP1_PARAM_BASE | i,
 					      .planes = paramPool_.buffers()[i].planes() });
 		paramBuffers_.push(new Buffer(i));
 	}
 
-	for (unsigned int i = 0; i < stream->configuration().bufferCount + 1; i++) {
+	for (unsigned int i = 0; i < stream->configuration().bufferCount; i++) {
 		data->ipaBuffers_.push_back({ .id = RKISP1_STAT_BASE | i,
 					      .planes = statPool_.buffers()[i].planes() });
 		statBuffers_.push(new Buffer(i));
@@ -981,9 +981,9 @@ void PipelineHandlerRkISP1::tryCompleteRequest(Request *request)
 	if (!info->paramDequeued)
 		return;
 
-	completeRequest(activeCamera_, request);
-
 	data->frameInfo_.destroy(info->frame);
+
+	completeRequest(activeCamera_, request);
 }
 
 void PipelineHandlerRkISP1::bufferReady(Buffer *buffer)
-- 
2.24.1