android: Remove CameraWorker

The CameraWorker class purpose was to handle acquire fences for incoming
capture requests directed to libcamera.

Now that fences are handled by the core library, it is not required to
handle them in the HAL and the CameraWorker and CaptureRequest classes
can be dropped.

Update the core in CameraDevice class accordingly to queue Requests
directly to the libcamera::Camera and set the release_fence to the
value of the FrameBuffer::fence() for streams of type ::Direct.

While at it make CameraRequest::StreamBuffer::fence a UniqueFD to ease
the management of the fences file descriptor values.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/android/camera_device.cpp

@@ -14,10 +14,12 @@
 #include <vector>
 
 #include <libcamera/base/log.h>
+#include <libcamera/base/unique_fd.h>
 #include <libcamera/base/utils.h>
 
 #include <libcamera/control_ids.h>
 #include <libcamera/controls.h>
+#include <libcamera/fence.h>
 #include <libcamera/formats.h>
 #include <libcamera/property_ids.h>
 
@@ -420,7 +422,6 @@ void CameraDevice::flush()
 		state_ = State::Flushing;
 	}
 
-	worker_.stop();
 	camera_->stop();
 
 	MutexLocker stateLock(stateMutex_);
@@ -433,7 +434,6 @@ void CameraDevice::stop()
 	if (state_ == State::Stopped)
 		return;
 
-	worker_.stop();
 	camera_->stop();
 
 	{
@@ -930,13 +930,10 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 
 		/*
 		 * Inspect the camera stream type, create buffers opportunely
-		 * and add them to the Request if required. Only acquire fences
-		 * for streams of type Direct are handled by the CameraWorker,
-		 * while fences for streams of type Internal and Mapped are
-		 * handled at post-processing time.
+		 * and add them to the Request if required.
 		 */
 		FrameBuffer *frameBuffer = nullptr;
-		int acquireFence = -1;
+		UniqueFD acquireFence;
 
 		MutexLocker lock(descriptor->streamsProcessMutex_);
 
@@ -964,7 +961,7 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 						  cameraStream->configuration().pixelFormat,
 						  cameraStream->configuration().size);
 			frameBuffer = buffer.frameBuffer.get();
-			acquireFence = buffer.fence;
+			acquireFence = std::move(buffer.fence);
 			LOG(HAL, Debug) << ss.str() << " (direct)";
 			break;
 
@@ -990,13 +987,14 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 			return -ENOMEM;
 		}
 
+		auto fence = std::make_unique<Fence>(std::move(acquireFence));
 		descriptor->request_->addBuffer(cameraStream->stream(),
-						frameBuffer, acquireFence);
+						frameBuffer, std::move(fence));
 	}
 
 	/*
 	 * Translate controls from Android to libcamera and queue the request
-	 * to the CameraWorker thread.
+	 * to the camera.
 	 */
 	int ret = processControls(descriptor.get());
 	if (ret)
@@ -1022,26 +1020,23 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
 	}
 
 	if (state_ == State::Stopped) {
-		worker_.start();
-
 		ret = camera_->start();
 		if (ret) {
 			LOG(HAL, Error) << "Failed to start camera";
-			worker_.stop();
 			return ret;
 		}
 
 		state_ = State::Running;
 	}
 
-	CaptureRequest *request = descriptor->request_.get();
+	Request *request = descriptor->request_.get();
 
 	{
 		MutexLocker descriptorsLock(descriptorsMutex_);
 		descriptors_.push(std::move(descriptor));
 	}
 
-	worker_.queueRequest(request);
+	camera_->queueRequest(request);
 
 	return 0;
 }
@@ -1063,16 +1058,17 @@ void CameraDevice::requestComplete(Request *request)
 		/*
 		 * Streams of type Direct have been queued to the
 		 * libcamera::Camera and their acquire fences have
-		 * already been waited on by the CameraWorker.
+		 * already been waited on by the library.
 		 *
 		 * Acquire fences of streams of type Internal and Mapped
 		 * will be handled during post-processing.
-		 *
-		 * \todo Instrument the CameraWorker to set the acquire
-		 * fence to -1 once it has handled it and remove this check.
 		 */
-		if (stream->type() == CameraStream::Type::Direct)
-			buffer.fence = -1;
+		if (stream->type() == CameraStream::Type::Direct) {
+			/* If handling of the fence has failed restore buffer.fence. */
+			std::unique_ptr<Fence> fence = buffer.frameBuffer->releaseFence();
+			if (fence)
+				buffer.fence = fence->release();
+		}
 		buffer.status = Camera3RequestDescriptor::Status::Success;
 	}
 
@@ -1193,7 +1189,7 @@ void CameraDevice::sendCaptureResults()
 		std::vector<camera3_stream_buffer_t> resultBuffers;
 		resultBuffers.reserve(descriptor->buffers_.size());
 
-		for (const auto &buffer : descriptor->buffers_) {
+		for (auto &buffer : descriptor->buffers_) {
 			camera3_buffer_status status = CAMERA3_BUFFER_STATUS_ERROR;
 
 			if (buffer.status == Camera3RequestDescriptor::Status::Success)
@@ -1207,7 +1203,7 @@ void CameraDevice::sendCaptureResults()
 			 */
 			resultBuffers.push_back({ buffer.stream->camera3Stream(),
 						  buffer.camera3Buffer, status,
-						  -1, buffer.fence });
+						  -1, buffer.fence.release() });
 		}
 
 		captureResult.num_output_buffers = resultBuffers.size();