[libcamera-devel] [PATCH v1 5/5] cam: Move request processing to main thread

[Laurent Pinchart]

The request completion handler is invoked in the camera manager thread,
which shouldn't be blocked for large amounts of time. As writing the
frames to disk can be a time-consuming process, move request processing
to the main thread by queueing an event to the event loop.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/cam/capture.cpp | 9 +++++++++
 src/cam/capture.h   | 1 +
 2 files changed, 10 insertions(+)

diff --git a/src/cam/capture.cpp b/src/cam/capture.cpp
index 7580f798288c..43b109d099f6 100644
--- a/src/cam/capture.cpp
+++ b/src/cam/capture.cpp
@@ -157,6 +157,15 @@ void Capture::requestComplete(Request *request)
 	if (request->status() == Request::RequestCancelled)
 		return;
 
+	/*
+	 * Defer processing of the completed request to the event loop, to avoid
+	 * blocking the camera manager thread.
+	 */
+	loop_->callLater(std::bind(&Capture::processRequest, this, request));
+}
+
+void Capture::processRequest(Request *request)
+{
 	const Request::BufferMap &buffers = request->buffers();
 
 	/*
diff --git a/src/cam/capture.h b/src/cam/capture.h
index 45e5e8a9ba27..d21c95a26ce7 100644
--- a/src/cam/capture.h
+++ b/src/cam/capture.h
@@ -33,6 +33,7 @@ private:
 	int capture(libcamera::FrameBufferAllocator *allocator);
 
 	void requestComplete(libcamera::Request *request);
+	void processRequest(libcamera::Request *request);
 
 	std::shared_ptr<libcamera::Camera> camera_;
 	libcamera::CameraConfiguration *config_;
-- 
Regards,

Laurent Pinchart