[libcamera-devel] [PATCH v2 3/6] pipeline: raspberrypi: Free buffers in the RPiCamera destructor and re-configure

[Naushir Patuck]

Currently, all framebuffer allocations get freed and cleared on a stop in
PipelineHandlerRPi::stopDevice(). If PipelineHandlerRPi::start() is then called
without an intermediate PipelineHandlerRPi::configure(), it will re-allocate and
prepare all the buffers again, which is unnecessary.

Fix this by not freeing the buffer in PipelineHandlerRPi::stopDevice(), but
insted doing it in PipelineHandlerRPi::configure(), as the buffers might have
to be resized.

Add a flag to indicate that buffer allocations need to be done on the next
call to PipelineHandlerRPi::start().

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
Tested-by: David Plowman <david.plowman at raspberrypi.com>
---
 .../pipeline/raspberrypi/raspberrypi.cpp      | 33 +++++++++++++------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 2281b43fc3ac..082273828894 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -185,10 +185,15 @@ public:
 	RPiCameraData(PipelineHandler *pipe)
 		: Camera::Private(pipe), state_(State::Stopped),
 		  supportsFlips_(false), flipsAlterBayerOrder_(false),
-		  dropFrameCount_(0), ispOutputCount_(0)
+		  dropFrameCount_(0), reallocate_(true), ispOutputCount_(0)
 	{
 	}
 
+	~RPiCameraData()
+	{
+		freeBuffers();
+	}
+
 	void freeBuffers();
 	void frameStarted(uint32_t sequence);
 
@@ -280,6 +285,9 @@ public:
 	 */
 	std::optional<int32_t> notifyGainsUnity_;
 
+	/* Has this camera been reconfigured? */
+	bool reallocate_;
+
 private:
 	void checkRequestCompleted();
 	void fillRequestMetadata(const ControlList &bufferControls,
@@ -682,7 +690,8 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	RPiCameraData *data = cameraData(camera);
 	int ret;
 
-	/* Start by resetting the Unicam and ISP stream states. */
+	/* Start by freeing all buffers and reset the Unicam and ISP stream states. */
+	data->freeBuffers();
 	for (auto const stream : data->streams_)
 		stream->reset();
 
@@ -982,12 +991,16 @@ int PipelineHandlerRPi::start(Camera *camera, const ControlList *controls)
 	RPiCameraData *data = cameraData(camera);
 	int ret;
 
-	/* Allocate buffers for internal pipeline usage. */
-	ret = prepareBuffers(camera);
-	if (ret) {
-		LOG(RPI, Error) << "Failed to allocate buffers";
-		stop(camera);
-		return ret;
+	if (data->reallocate_) {
+		/* Allocate buffers for internal pipeline usage. */
+		ret = prepareBuffers(camera);
+		if (ret) {
+			LOG(RPI, Error) << "Failed to allocate buffers";
+			data->freeBuffers();
+			stop(camera);
+			return ret;
+		}
+		data->reallocate_ = false;
 	}
 
 	/* Check if a ScalerCrop control was specified. */
@@ -1055,8 +1068,6 @@ void PipelineHandlerRPi::stopDevice(Camera *camera)
 
 	/* Stop the IPA. */
 	data->ipa_->stop();
-
-	data->freeBuffers();
 }
 
 int PipelineHandlerRPi::queueRequestDevice(Camera *camera, Request *request)
@@ -1461,6 +1472,8 @@ void RPiCameraData::freeBuffers()
 
 	for (auto const stream : streams_)
 		stream->releaseBuffers();
+
+	reallocate_ = true;
 }
 
 void RPiCameraData::frameStarted(uint32_t sequence)
-- 
2.25.1