[libcamera-devel] [PATCH v2 4/6] pipeline: raspberrypi: Repurpose RPi::Stream::reset()

[Naushir Patuck]

The original use of RPi::Stream::reset() was to clear the external flag state
and free/clear out the framebuffers for the stream. However, the latter is now
done through PipelineHandlerRPi::configure(). Rework
PipelineHandlerRPi::configure() to call RPi::Stream::setExternal() instead of
RPi::Stream::reset() to achieve the same thing.

Repurpose RPi::Stream::reset() to instead reset the state of the buffer handling
logic, where all internally allocated buffers are put back into the queue of
available buffers. As such, rename the function to RPi::Stream::resetbuffers()
This resetbuffers() is now called from PipelineHandlerRPi::start(), allowing the
pipeline handler to correctly deal with start()/stop()/start() sequences and
reusing the buffers allocated on the first 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>
---
 src/libcamera/pipeline/raspberrypi/raspberrypi.cpp |  7 +++++--
 src/libcamera/pipeline/raspberrypi/rpi_stream.cpp  | 13 ++++++-------
 src/libcamera/pipeline/raspberrypi/rpi_stream.h    |  2 +-
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 082273828894..d3212b193ced 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -693,7 +693,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	/* Start by freeing all buffers and reset the Unicam and ISP stream states. */
 	data->freeBuffers();
 	for (auto const stream : data->streams_)
-		stream->reset();
+		stream->setExternal(false);
 
 	BayerFormat::Packing packing = BayerFormat::Packing::CSI2;
 	Size maxSize, sensorSize;
@@ -991,6 +991,9 @@ int PipelineHandlerRPi::start(Camera *camera, const ControlList *controls)
 	RPiCameraData *data = cameraData(camera);
 	int ret;
 
+	for (auto const stream : data->streams_)
+		stream->resetBuffers();
+
 	if (data->reallocate_) {
 		/* Allocate buffers for internal pipeline usage. */
 		ret = prepareBuffers(camera);
@@ -1031,7 +1034,7 @@ int PipelineHandlerRPi::start(Camera *camera, const ControlList *controls)
 	data->unicam_[Unicam::Image].dev()->setFrameStartEnabled(true);
 
 	/*
-	 * Reset the delayed controls with the gain and exposure values set by
+	 * resetBuffers the delayed controls with the gain and exposure values set by
 	 * the IPA.
 	 */
 	data->delayedCtrls_->reset();
diff --git a/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp b/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
index f446e1ce66c7..7a93efaa29da 100644
--- a/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
+++ b/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
@@ -26,10 +26,12 @@ std::string Stream::name() const
 	return name_;
 }
 
-void Stream::reset()
+void Stream::resetBuffers()
 {
-	external_ = false;
-	clearBuffers();
+	/* Add all internal buffers to the queue of usable buffers. */
+	availableBuffers_ = {};
+	for (auto const &buffer : internalBuffers_)
+		availableBuffers_.push(buffer.get());
 }
 
 void Stream::setExternal(bool external)
@@ -97,10 +99,7 @@ int Stream::prepareBuffers(unsigned int count)
 
 			/* Add these exported buffers to the internal/external buffer list. */
 			setExportedBuffers(&internalBuffers_);
-
-			/* Add these buffers to the queue of internal usable buffers. */
-			for (auto const &buffer : internalBuffers_)
-				availableBuffers_.push(buffer.get());
+			resetBuffers();
 		}
 
 		/* We must import all internal/external exported buffers. */
diff --git a/src/libcamera/pipeline/raspberrypi/rpi_stream.h b/src/libcamera/pipeline/raspberrypi/rpi_stream.h
index d6f49d34f8c8..c37f7e82eef6 100644
--- a/src/libcamera/pipeline/raspberrypi/rpi_stream.h
+++ b/src/libcamera/pipeline/raspberrypi/rpi_stream.h
@@ -45,7 +45,7 @@ public:
 	V4L2VideoDevice *dev() const;
 	std::string name() const;
 	bool isImporter() const;
-	void reset();
+	void resetBuffers();
 
 	void setExternal(bool external);
 	bool isExternal() const;
-- 
2.25.1