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libcamera: v4l2_videodevice: Track streaming state

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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@ideasonboard.com>
Signed-off-by: Umang Jain <email@uajain.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
This commit is contained in:
Kieran Bingham 2021-01-12 10:21:39 +05:30
parent 5988661c90
commit c0bad607ce
2 changed files with 13 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

2
include/libcamera/internal/v4l2_videodevice.h
View file

@ -249,6 +249,8 @@ private:
std::map<unsigned int, FrameBuffer *> queuedBuffers_; std::map<unsigned int, FrameBuffer *> queuedBuffers_;
EventNotifier *fdBufferNotifier_; EventNotifier *fdBufferNotifier_;
bool streaming_;
}; };
class V4L2M2MDevice class V4L2M2MDevice

12
src/libcamera/v4l2_videodevice.cpp
View file

@ -481,7 +481,8 @@ const std::string V4L2DeviceFormat::toString() const
* \param[in] deviceNode The file-system path to the video device node * \param[in] deviceNode The file-system path to the video device node
*/ */
V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode) 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 * We default to an MMAP based CAPTURE video device, however this will
@ -1554,6 +1555,8 @@ int V4L2VideoDevice::streamOn()
return ret; return ret;
} }
streaming_ = true;
return 0; return 0;
} }
@ -1565,12 +1568,18 @@ int V4L2VideoDevice::streamOn()
* and the bufferReady signal is emitted for them. The order in which those * and the bufferReady signal is emitted for them. The order in which those
* buffers are dequeued is not specified. * 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 * \return 0 on success or a negative error code otherwise
*/ */
int V4L2VideoDevice::streamOff() int V4L2VideoDevice::streamOff()
{ {
int ret; int ret;
if (!streaming_ && queuedBuffers_.empty())
return 0;
ret = ioctl(VIDIOC_STREAMOFF, &bufferType_); ret = ioctl(VIDIOC_STREAMOFF, &bufferType_);
if (ret < 0) { if (ret < 0) {
LOG(V4L2, Error) LOG(V4L2, Error)
@ -1588,6 +1597,7 @@ int V4L2VideoDevice::streamOff()
queuedBuffers_.clear(); queuedBuffers_.clear();
fdBufferNotifier_->setEnabled(false); fdBufferNotifier_->setEnabled(false);
streaming_ = false;
return 0; return 0;
} }