v4l2: Remove internal thread

Now that libcamera creates threads internally and doesn't rely on an
application-provided event loop, remove the thread from the V4L2
compatibility layer. The split between the V4L2CameraProxy and
V4L2Camera classes is still kept to separate the V4L2 adaptation from
camera operation. This may be further refactored later.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/v4l2/v4l2_camera.h

@@ -21,7 +21,7 @@
 
 using namespace libcamera;
 
-class V4L2Camera : public Object
+class V4L2Camera
 {
 public:
 	struct Buffer {

src/v4l2/v4l2_camera_proxy.cpp

@@ -41,8 +41,7 @@ int V4L2CameraProxy::open(bool nonBlocking)
 {
 	LOG(V4L2Compat, Debug) << "Servicing open";
 
-	int ret = vcam_->invokeMethod(&V4L2Camera::open,
+	int ret = vcam_->open();
-				      ConnectionTypeBlocking);
 	if (ret < 0) {
 		errno = -ret;
 		return -1;
@@ -50,8 +49,7 @@ int V4L2CameraProxy::open(bool nonBlocking)
 
 	nonBlocking_ = nonBlocking;
 
-	vcam_->invokeMethod(&V4L2Camera::getStreamConfig,
+	vcam_->getStreamConfig(&streamConfig_);
-			    ConnectionTypeBlocking, &streamConfig_);
 	setFmtFromConfig(streamConfig_);
 	sizeimage_ = calculateSizeImage(streamConfig_);
 
@@ -72,7 +70,7 @@ void V4L2CameraProxy::close()
 	if (--refcount_ > 0)
 		return;
 
-	vcam_->invokeMethod(&V4L2Camera::close, ConnectionTypeBlocking);
+	vcam_->close();
 }
 
 void *V4L2CameraProxy::mmap(void *addr, size_t length, int prot, int flags,
@@ -284,11 +282,9 @@ int V4L2CameraProxy::vidioc_s_fmt(struct v4l2_format *arg)
 	tryFormat(arg);
 
 	Size size(arg->fmt.pix.width, arg->fmt.pix.height);
-	int ret = vcam_->invokeMethod(&V4L2Camera::configure,
+	int ret = vcam_->configure(&streamConfig_, size,
-				      ConnectionTypeBlocking,
+				   v4l2ToDrm(arg->fmt.pix.pixelformat),
-				      &streamConfig_, size,
+				   bufferCount_);
-				      v4l2ToDrm(arg->fmt.pix.pixelformat),
-				      bufferCount_);
 	if (ret < 0)
 		return -EINVAL;
 
@@ -319,13 +315,12 @@ int V4L2CameraProxy::freeBuffers()
 {
 	LOG(V4L2Compat, Debug) << "Freeing libcamera bufs";
 
-	int ret = vcam_->invokeMethod(&V4L2Camera::streamOff,
+	int ret = vcam_->streamOff();
-				      ConnectionTypeBlocking);
 	if (ret < 0) {
 		LOG(V4L2Compat, Error) << "Failed to stop stream";
 		return ret;
 	}
-	vcam_->invokeMethod(&V4L2Camera::freeBuffers, ConnectionTypeBlocking);
+	vcam_->freeBuffers();
 	bufferCount_ = 0;
 
 	return 0;
@@ -349,11 +344,9 @@ int V4L2CameraProxy::vidioc_reqbufs(struct v4l2_requestbuffers *arg)
 		return freeBuffers();
 
 	Size size(curV4L2Format_.fmt.pix.width, curV4L2Format_.fmt.pix.height);
-	ret = vcam_->invokeMethod(&V4L2Camera::configure,
+	ret = vcam_->configure(&streamConfig_, size,
-				  ConnectionTypeBlocking,
+			       v4l2ToDrm(curV4L2Format_.fmt.pix.pixelformat),
-				  &streamConfig_, size,
+			       arg->count);
-				  v4l2ToDrm(curV4L2Format_.fmt.pix.pixelformat),
-				  arg->count);
 	if (ret < 0)
 		return -EINVAL;
 
@@ -366,8 +359,7 @@ int V4L2CameraProxy::vidioc_reqbufs(struct v4l2_requestbuffers *arg)
 	arg->count = streamConfig_.bufferCount;
 	bufferCount_ = arg->count;
 
-	ret = vcam_->invokeMethod(&V4L2Camera::allocBuffers,
+	ret = vcam_->allocBuffers(arg->count);
-				  ConnectionTypeBlocking, arg->count);
 	if (ret < 0) {
 		arg->count = 0;
 		return ret;
@@ -415,8 +407,7 @@ int V4L2CameraProxy::vidioc_qbuf(struct v4l2_buffer *arg)
 	    arg->index >= bufferCount_)
 		return -EINVAL;
 
-	int ret = vcam_->invokeMethod(&V4L2Camera::qbuf, ConnectionTypeBlocking,
+	int ret = vcam_->qbuf(arg->index);
-				      arg->index);
 	if (ret < 0)
 		return ret;
 
@@ -459,10 +450,7 @@ int V4L2CameraProxy::vidioc_streamon(int *arg)
 	if (!validateBufferType(*arg))
 		return -EINVAL;
 
-	int ret = vcam_->invokeMethod(&V4L2Camera::streamOn,
+	return vcam_->streamOn();
-				      ConnectionTypeBlocking);
-
-	return ret;
 }
 
 int V4L2CameraProxy::vidioc_streamoff(int *arg)
@@ -472,8 +460,7 @@ int V4L2CameraProxy::vidioc_streamoff(int *arg)
 	if (!validateBufferType(*arg))
 		return -EINVAL;
 
-	int ret = vcam_->invokeMethod(&V4L2Camera::streamOff,
+	int ret = vcam_->streamOff();
-				      ConnectionTypeBlocking);
 
 	for (struct v4l2_buffer &buf : buffers_)
 		buf.flags &= ~(V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE);

src/v4l2/v4l2_compat_manager.cpp

@@ -37,7 +37,7 @@ void get_symbol(T &func, const char *name)
 } /* namespace */
 
 V4L2CompatManager::V4L2CompatManager()
-	: cm_(nullptr), initialized_(false)
+	: cm_(nullptr)
 {
 	get_symbol(fops_.openat, "openat");
 	get_symbol(fops_.dup, "dup");
@@ -52,24 +52,15 @@ V4L2CompatManager::~V4L2CompatManager()
 	devices_.clear();
 	mmaps_.clear();
 
-	if (isRunning()) {
+	if (cm_) {
-		exit(0);
+		proxies_.clear();
-		/* \todo Wait with a timeout, just in case. */
+		cm_->stop();
-		wait();
+		delete cm_;
+		cm_ = nullptr;
 	}
 }
 
-int V4L2CompatManager::init()
+int V4L2CompatManager::start()
-{
-	start();
-
-	MutexLocker locker(mutex_);
-	cv_.wait(locker, [&] { return initialized_; });
-
-	return 0;
-}
-
-void V4L2CompatManager::run()
 {
 	cm_ = new CameraManager();
 
@@ -77,7 +68,9 @@ void V4L2CompatManager::run()
 	if (ret) {
 		LOG(V4L2Compat, Error) << "Failed to start camera manager: "
 				       << strerror(-ret);
-		return;
+		delete cm_;
+		cm_ = nullptr;
+		return ret;
 	}
 
 	LOG(V4L2Compat, Debug) << "Started camera manager";
@@ -93,22 +86,7 @@ void V4L2CompatManager::run()
 		++index;
 	}
 
-	/*
+	return 0;
-	 * libcamera has been initialized. Unlock the init() caller as we're
-	 * now ready to handle calls from the framework.
-	 */
-	mutex_.lock();
-	initialized_ = true;
-	mutex_.unlock();
-	cv_.notify_one();
-
-	/* Now start processing events and messages. */
-	exec();
-
-	proxies_.clear();
-	cm_->stop();
-	delete cm_;
-	cm_ = nullptr;
 }
 
 V4L2CompatManager *V4L2CompatManager::instance()
@@ -159,8 +137,8 @@ int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mod
 	    major(statbuf.st_rdev) != 81)
 		return fd;
 
-	if (!isRunning())
+	if (!cm_)
-		init();
+		start();
 
 	ret = getCameraIndex(fd);
 	if (ret < 0) {

src/v4l2/v4l2_compat_manager.h

@@ -8,22 +8,19 @@
 #ifndef __V4L2_COMPAT_MANAGER_H__
 #define __V4L2_COMPAT_MANAGER_H__
 
-#include <condition_variable>
 #include <fcntl.h>
 #include <map>
 #include <memory>
-#include <mutex>
 #include <sys/types.h>
 #include <vector>
 
 #include <libcamera/camera_manager.h>
 
-#include "thread.h"
 #include "v4l2_camera_proxy.h"
 
 using namespace libcamera;
 
-class V4L2CompatManager : public Thread
+class V4L2CompatManager
 {
 public:
 	struct FileOperations {
@@ -46,8 +43,6 @@ public:
 
 	static V4L2CompatManager *instance();
 
-	int init();
-
 	V4L2CameraProxy *getProxy(int fd);
 	const FileOperations &fops() const { return fops_; }
 
@@ -64,17 +59,13 @@ private:
 	V4L2CompatManager();
 	~V4L2CompatManager();
 
-	void run() override;
+	int start();
 	int getCameraIndex(int fd);
 
 	FileOperations fops_;
 
 	CameraManager *cm_;
 
-	std::mutex mutex_;
-	std::condition_variable cv_;
-	bool initialized_;
-
 	std::vector<std::unique_ptr<V4L2CameraProxy>> proxies_;
 	std::map<int, V4L2CameraProxy *> devices_;
 	std::map<void *, V4L2CameraProxy *> mmaps_;