core: Reduce the camera manager init calls if possible.

The camera manager may be initialised multiple times depending on the
current and wanted state of the sensor HDR control. Avoid this by
having the camera manager accessable from the Options class and only
re-initialising it if the state of the sensor HDR control has changed.
Do this carefully enough, and there ought to be no change in behaviour
perceived by a application or the user.

Signed-off-by: Naushir Patuck <[email protected]>

core/libcamera_app.cpp

@@ -137,6 +137,8 @@ LibcameraApp::LibcameraApp(std::unique_ptr<Options> opts)
 	if (!options_)
 		options_ = std::make_unique<Options>();
 
+	options_->SetApp(this);
+
 	set_pipeline_configuration(platform);
 }
 
@@ -151,6 +153,15 @@ LibcameraApp::~LibcameraApp()
 	CloseCamera();
 }
 
+void LibcameraApp::initCameraManager()
+{
+	camera_manager_.reset();
+	camera_manager_ = std::make_unique<CameraManager>();
+	int ret = camera_manager_->start();
+	if (ret)
+		throw std::runtime_error("camera manager failed to start, code " + std::to_string(-ret));
+}
+
 std::string const &LibcameraApp::CameraId() const
 {
 	return camera_->id();
@@ -170,14 +181,13 @@ void LibcameraApp::OpenCamera()
 
 	LOG(2, "Opening camera...");
 
-	camera_manager_ = std::make_unique<CameraManager>();
-	int ret = camera_manager_->start();
-	if (ret)
-		throw std::runtime_error("camera manager failed to start, code " + std::to_string(-ret));
+	if (!camera_manager_)
+		initCameraManager();
 
 	std::vector<std::shared_ptr<libcamera::Camera>> cameras = GetCameras();
 	if (cameras.size() == 0)
 		throw std::runtime_error("no cameras available");
+
 	if (options_->camera >= cameras.size())
 		throw std::runtime_error("selected camera is not available");
 

core/libcamera_app.hpp

@@ -179,6 +179,7 @@ class LibcameraApp
 
 	friend class BufferWriteSync;
 	friend class BufferReadSync;
+	friend class Options;
 
 protected:
 	std::unique_ptr<Options> options_;
@@ -229,6 +230,7 @@ class LibcameraApp
 		Stream *stream;
 	};
 
+	void initCameraManager();
 	void setupCapture();
 	void makeRequests();
 	void queueRequest(CompletedRequest *completed_request);
@@ -241,6 +243,7 @@ class LibcameraApp
 	Mode selectMode(const Mode &mode) const;
 
 	std::unique_ptr<CameraManager> camera_manager_;
+	std::vector<std::shared_ptr<libcamera::Camera>> cameras_;
 	std::shared_ptr<Camera> camera_;
 	bool camera_acquired_ = false;
 	std::unique_ptr<CameraConfiguration> configuration_;

core/options.cpp

@@ -104,8 +104,9 @@ static int xioctl(int fd, unsigned long ctl, void *arg)
 	return ret;
 }
 
-static void set_subdev_hdr_ctrl(int en)
+static bool set_subdev_hdr_ctrl(int en)
 {
+	bool changed = false;
 	// Currently this does not exist in libcamera, so go directly to V4L2
 	// XXX it's not obvious which v4l2-subdev to use for which camera!
 	for (int i = 0; i < 8; i++)
@@ -117,9 +118,17 @@ static void set_subdev_hdr_ctrl(int en)
 			continue;
 
 		v4l2_control ctrl { V4L2_CID_WIDE_DYNAMIC_RANGE, en };
-		xioctl(fd, VIDIOC_S_CTRL, &ctrl);
+		xioctl(fd, VIDIOC_G_CTRL, &ctrl);
+		if (ctrl.value != en)
+		{
+			ctrl.value = en;
+			xioctl(fd, VIDIOC_S_CTRL, &ctrl);
+			changed = true;
+		}
 		close(fd);
 	}
+
+	return changed;
 }
 
 bool Options::Parse(int argc, char *argv[])
@@ -164,70 +173,55 @@ bool Options::Parse(int argc, char *argv[])
 	shutter.set(shutter_);
 	flicker_period.set(flicker_period_);
 
+	if (help)
+	{
+		std::cout << options_;
+		return false;
+	}
+
+	if (version)
+	{
+		std::cout << "libcamera-apps build: " << LibcameraAppsVersion() << std::endl;
+		std::cout << "libcamera build: " << libcamera::CameraManager::version() << std::endl;
+		return false;
+	}
+
 	if (hdr != "off" && hdr != "single-exp" && hdr != "sensor" && hdr != "auto")
 		throw std::runtime_error("Invalid HDR option provided: " + hdr);
 
-	logSetTarget(LoggingTargetNone);
+	if (!verbose || list_cameras)
+		libcamera::logSetTarget(libcamera::LoggingTargetNone);
 
 	// HDR control. Set the sensor control before opening or listing any cameras.
-	// Start by disabling HDR unconditionally.
+	// Start by disabling HDR unconditionally. Reset the camera manager if we have
+	// actually switched the value of the control.
 	set_subdev_hdr_ctrl(0);
+	app_->initCameraManager();
 
-	std::unique_ptr<CameraManager> cm = std::make_unique<CameraManager>();
-	int ret = cm->start();
-	if (ret)
-		throw std::runtime_error("camera manager failed to start, code " + std::to_string(-ret));
+	// Unconditionally disable libcamera logging for a bit.
+	libcamera::logSetTarget(libcamera::LoggingTargetNone);
 
-	std::vector<std::shared_ptr<libcamera::Camera>> cameras = LibcameraApp::GetCameras(cm.get());
+	std::vector<std::shared_ptr<libcamera::Camera>> cameras = app_->GetCameras();
 	std::string const &cam_id = *cameras[camera]->properties().get(libcamera::properties::Model);
-	cameras.clear();
-	cm->stop();
-	cm.reset();
 
 	if ((hdr == "sensor" || hdr == "auto") && cam_id == "imx708")
 	{
-		set_subdev_hdr_ctrl(1);
+		// Turn on sensor HDR.  Reset the camera manager if we have switched the value of the control.
+		if (set_subdev_hdr_ctrl(1))
+		{
+			cameras.clear();
+			app_->initCameraManager();
+			cameras = app_->GetCameras();
+		}
 		hdr = "sensor";
 	}
 
-	logSetTarget(LoggingTargetStream);
-
-	// We have to pass the tuning file name through an environment variable.
-	// Note that we only overwrite the variable if the option was given.
-	if (tuning_file != "-")
-		setenv("LIBCAMERA_RPI_TUNING_FILE", tuning_file.c_str(), 1);
-
-	// Set the verbosity
-	LibcameraApp::verbosity = verbose;
-
-	if (verbose == 0)
-		libcamera::logSetTarget(libcamera::LoggingTargetNone);
-
-	if (help)
-	{
-		std::cout << options_;
-		return false;
-	}
-
-	if (version)
-	{
-		std::cout << "libcamera-apps build: " << LibcameraAppsVersion() << std::endl;
-		std::cout << "libcamera build: " << libcamera::CameraManager::version() << std::endl;
-		return false;
-	}
-
 	if (list_cameras)
 	{
 		// Disable any libcamera logging for this bit.
 		logSetTarget(LoggingTargetNone);
 		LibcameraApp::verbosity = 1;
 
-		std::unique_ptr<CameraManager> cm = std::make_unique<CameraManager>();
-		int ret = cm->start();
-		if (ret)
-			throw std::runtime_error("camera manager failed to start, code " + std::to_string(-ret));
-
-		std::vector<std::shared_ptr<libcamera::Camera>> cameras = LibcameraApp::GetCameras(cm.get());
 		if (cameras.size() != 0)
 		{
 			unsigned int idx = 0;
@@ -341,11 +335,21 @@ bool Options::Parse(int argc, char *argv[])
 			std::cout << "No cameras available!" << std::endl;
 
 		verbose = 1;
-		cameras.clear();
-		cm->stop();
 		return false;
 	}
 
+	// Reset verbosity to the user request.
+	if (verbose)
+		libcamera::logSetTarget(libcamera::LoggingTargetStream);
+
+	// Set the verbosity
+	LibcameraApp::verbosity = verbose;
+
+	// We have to pass the tuning file name through an environment variable.
+	// Note that we only overwrite the variable if the option was given.
+	if (tuning_file != "-")
+		setenv("LIBCAMERA_RPI_TUNING_FILE", tuning_file.c_str(), 1);
+
 	if (sscanf(preview.c_str(), "%u,%u,%u,%u", &preview_x, &preview_y, &preview_width, &preview_height) != 4)
 		preview_x = preview_y = preview_width = preview_height = 0; // use default window
 

core/options.hpp

@@ -94,7 +94,8 @@ struct TimeVal
 
 struct Options
 {
-	Options() : set_default_lens_position(false), af_on_capture(false), options_("Valid options are", 120, 80)
+	Options()
+		: set_default_lens_position(false), af_on_capture(false), options_("Valid options are", 120, 80), app_(nullptr)
 	{
 		using namespace boost::program_options;
 		// clang-format off
@@ -290,6 +291,8 @@ struct Options
 	virtual bool Parse(int argc, char *argv[]);
 	virtual void Print() const;
 
+	void SetApp(LibcameraApp *app) { app_ = app; }
+
 protected:
 	boost::program_options::options_description options_;
 
@@ -302,4 +305,5 @@ struct Options
 	std::string timeout_;
 	std::string shutter_;
 	std::string flicker_period_;
+	LibcameraApp *app_;
 };