test: v4l2_videodevice: Verify the Dequeue Watchdog

Add a test that captures 5 frames, with a short (5ms) watchdog.
The default framerate of the VIMC pipeline should ensure that
we never meet this watchdog, and the timeout should activate.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

test/v4l2_videodevice/dequeue_watchdog.cpp

@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2022, Ideas on Board Oy.
+ *
+ * libcamera V4L2 dequeue watchdog test
+ */
+
+#include <iostream>
+
+#include <libcamera/base/event_dispatcher.h>
+#include <libcamera/base/thread.h>
+#include <libcamera/base/timer.h>
+
+#include <libcamera/framebuffer.h>
+
+#include "v4l2_videodevice_test.h"
+
+using namespace libcamera;
+using namespace std::chrono_literals;
+
+class DequeueWatchdogTest : public V4L2VideoDeviceTest
+{
+public:
+	DequeueWatchdogTest()
+		: V4L2VideoDeviceTest("vimc", "Raw Capture 0"), frames_(0), barks_(0) {}
+
+protected:
+	int run()
+	{
+		constexpr unsigned int bufferCount = 8;
+
+		EventDispatcher *dispatcher = Thread::current()->eventDispatcher();
+		Timer timeout;
+
+		int ret = capture_->allocateBuffers(bufferCount, &buffers_);
+		if (ret < 0)
+			return TestFail;
+
+		capture_->dequeueTimeout.connect(this, &DequeueWatchdogTest::barkCounter);
+		capture_->setDequeueTimeout(5ms);
+
+		capture_->bufferReady.connect(this, &DequeueWatchdogTest::receiveBuffer);
+
+		for (const std::unique_ptr<FrameBuffer> &buffer : buffers_) {
+			if (capture_->queueBuffer(buffer.get())) {
+				std::cout << "Failed to queue buffer" << std::endl;
+				return TestFail;
+			}
+		}
+
+		capture_->streamOn();
+
+		timeout.start(5s);
+		while (timeout.isRunning()) {
+			dispatcher->processEvents();
+			if (frames_ > 5)
+				break;
+		}
+
+		std::cout << "Processed " << frames_ << " frames_ and heard "
+			  << barks_ << " barks_" << std::endl;
+
+		if (!barks_) {
+			std::cout << "Failed to hear any barks_." << std::endl;
+			return TestFail;
+		}
+
+		capture_->streamOff();
+
+		return TestPass;
+	}
+
+private:
+	void receiveBuffer(FrameBuffer *buffer)
+	{
+		if (buffer->metadata().status == FrameMetadata::FrameCancelled)
+			return;
+
+		std::cout << "Buffer received" << std::endl;
+		frames_++;
+
+		/* Requeue the buffer for further use. */
+		capture_->queueBuffer(buffer);
+	}
+
+	void barkCounter()
+	{
+		std::cout << "Watchdog is barking" << std::endl;
+		barks_++;
+	}
+
+	unsigned int frames_;
+	unsigned int barks_;
+};
+
+TEST_REGISTER(DequeueWatchdogTest)

test/v4l2_videodevice/meson.build

@@ -6,6 +6,7 @@ v4l2_videodevice_tests = [
     ['double_open',         'double_open.cpp'],
     ['controls',            'controls.cpp'],
     ['formats',             'formats.cpp'],
+    ['dequeue_watchdog',    'dequeue_watchdog.cpp'],
     ['request_buffers',     'request_buffers.cpp'],
     ['buffer_cache',        'buffer_cache.cpp'],
     ['stream_on_off',       'stream_on_off.cpp'],