[libcamera-devel] [PATCH v4 4/6] libcamera: pipeline: ipu3: Cancel unused buffers

[Kieran Bingham]

When the CIO2 returns a cancelled buffer, we will not queue buffers
to the IMGU.

These buffers should be explicitly marked as cancelled to ensure
the application knows there is no valid metadata or frame data
provided in the buffer.

Provide a cancel() method on the FrameBuffer to allow explicitly
cancelling a buffer.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 include/libcamera/buffer.h           | 2 ++
 src/libcamera/buffer.cpp             | 8 ++++++++
 src/libcamera/pipeline/ipu3/ipu3.cpp | 7 +++++--
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/libcamera/buffer.h b/include/libcamera/buffer.h
index 620f8a66f6a2..e0af00900409 100644
--- a/include/libcamera/buffer.h
+++ b/include/libcamera/buffer.h
@@ -53,6 +53,8 @@ public:
 	unsigned int cookie() const { return cookie_; }
 	void setCookie(unsigned int cookie) { cookie_ = cookie; }
 
+	void cancel() { metadata_.status = FrameMetadata::FrameCancelled; }
+
 private:
 	LIBCAMERA_DISABLE_COPY_AND_MOVE(FrameBuffer)
 
diff --git a/src/libcamera/buffer.cpp b/src/libcamera/buffer.cpp
index 75b2693281a7..7635226b9045 100644
--- a/src/libcamera/buffer.cpp
+++ b/src/libcamera/buffer.cpp
@@ -226,6 +226,14 @@ FrameBuffer::FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie)
  * core never modifies the buffer cookie.
  */
 
+/**
+ * \fn FrameBuffer::cancel()
+ * \brief Marks the buffer as cancelled
+ *
+ * If a buffer is not used by a request, it shall be marked as cancelled to
+ * indicate that the metadata is invalid.
+ */
+
 /**
  * \class MappedBuffer
  * \brief Provide an interface to support managing memory mapped buffers
diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 51446fcf5bc1..73306cea6b37 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -1257,8 +1257,11 @@ void IPU3CameraData::cio2BufferReady(FrameBuffer *buffer)
 
 	/* If the buffer is cancelled force a complete of the whole request. */
 	if (buffer->metadata().status == FrameMetadata::FrameCancelled) {
-		for (auto it : request->buffers())
-			pipe_->completeBuffer(request, it.second);
+		for (auto it : request->buffers()) {
+			FrameBuffer *b = it.second;
+			b->cancel();
+			pipe_->completeBuffer(request, b);
+		}
 
 		frameInfos_.remove(info);
 		pipe_->completeRequest(request);
-- 
2.25.1