[libcamera-devel] [PATCH] libcamera: v4l2_videodevice: Track streaming state

[Kieran Bingham]

Track the state of streamon/streamoff calls to simplify error paths.

Ensuring that streamOff() can be called on non-streaming streams
facilitates simpler error code paths, where a set of devices can all
call streamOff regardless of their initialisation state.

Acked-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---

Since RFC:
 - Rebased to master.

 src/libcamera/include/v4l2_videodevice.h |  2 ++
 src/libcamera/v4l2_videodevice.cpp       | 10 +++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/libcamera/include/v4l2_videodevice.h b/src/libcamera/include/v4l2_videodevice.h
index 4b8cf9394eb9..caf36bf9c1aa 100644
--- a/src/libcamera/include/v4l2_videodevice.h
+++ b/src/libcamera/include/v4l2_videodevice.h
@@ -187,6 +187,8 @@ private:
 	std::map<unsigned int, Buffer *> queuedBuffers_;
 
 	EventNotifier *fdEvent_;
+
+	bool streaming_;
 };
 
 class V4L2M2MDevice
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index 208ab54199b1..c0b3a79f76da 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -272,7 +272,8 @@ const std::string V4L2DeviceFormat::toString() const
  * \param[in] deviceNode The file-system path to the video device node
  */
 V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
-	: V4L2Device(deviceNode), bufferPool_(nullptr), fdEvent_(nullptr)
+	: V4L2Device(deviceNode), bufferPool_(nullptr), fdEvent_(nullptr),
+	  streaming_(false)
 {
 	/*
 	 * We default to an MMAP based CAPTURE video device, however this will
@@ -1173,6 +1174,8 @@ int V4L2VideoDevice::streamOn()
 		return ret;
 	}
 
+	streaming_ = true;
+
 	return 0;
 }
 
@@ -1190,6 +1193,9 @@ int V4L2VideoDevice::streamOff()
 {
 	int ret;
 
+	if (!streaming_)
+		return 0;
+
 	ret = ioctl(VIDIOC_STREAMOFF, &bufferType_);
 	if (ret < 0) {
 		LOG(V4L2, Error)
@@ -1210,6 +1216,8 @@ int V4L2VideoDevice::streamOff()
 	queuedBuffers_.clear();
 	fdEvent_->setEnabled(false);
 
+	streaming_ = false;
+
 	return 0;
 }
 
-- 
2.20.1