[libcamera-devel] [PATCH v2 1/2] libcamera: v4l2_videodevice: Track streaming state
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Tue Jan 12 06:30:56 CET 2021
Hi Umang and Kieran,
Thank you for the patch.
On Tue, Jan 12, 2021 at 10:21:39AM +0530, Umang Jain wrote:
> From: Kieran Bingham <kieran.bingham at ideasonboard.com>
>
> 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.
>
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Signed-off-by: Umang Jain <email at uajain.com>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
> include/libcamera/internal/v4l2_videodevice.h | 2 ++
> src/libcamera/v4l2_videodevice.cpp | 12 +++++++++++-
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
> index 529ca0e3..626dfbcd 100644
> --- a/include/libcamera/internal/v4l2_videodevice.h
> +++ b/include/libcamera/internal/v4l2_videodevice.h
> @@ -249,6 +249,8 @@ private:
> std::map<unsigned int, FrameBuffer *> queuedBuffers_;
>
> EventNotifier *fdBufferNotifier_;
> +
> + bool streaming_;
> };
>
> class V4L2M2MDevice
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index baf683d6..a9509bff 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -481,7 +481,8 @@ 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), cache_(nullptr), fdBufferNotifier_(nullptr)
> + : V4L2Device(deviceNode), cache_(nullptr), fdBufferNotifier_(nullptr),
> + streaming_(false)
> {
> /*
> * We default to an MMAP based CAPTURE video device, however this will
> @@ -1554,6 +1555,8 @@ int V4L2VideoDevice::streamOn()
> return ret;
> }
>
> + streaming_ = true;
> +
> return 0;
> }
>
> @@ -1565,12 +1568,18 @@ int V4L2VideoDevice::streamOn()
> * and the bufferReady signal is emitted for them. The order in which those
> * buffers are dequeued is not specified.
> *
> + * This will be a no-op if the stream is not started in the first place and
> + * has no queued buffers.
> + *
> * \return 0 on success or a negative error code otherwise
> */
> int V4L2VideoDevice::streamOff()
> {
> int ret;
>
> + if (!streaming_ && queuedBuffers_.empty())
> + return 0;
> +
> ret = ioctl(VIDIOC_STREAMOFF, &bufferType_);
> if (ret < 0) {
> LOG(V4L2, Error)
> @@ -1588,6 +1597,7 @@ int V4L2VideoDevice::streamOff()
>
> queuedBuffers_.clear();
> fdBufferNotifier_->setEnabled(false);
> + streaming_ = false;
>
> return 0;
> }
--
Regards,
Laurent Pinchart
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