[libcamera-devel] [PATCH v2 05/16] libcamera: v4l2_videodevice: Add helper to queue all buffers

Laurent Pinchart laurent.pinchart at ideasonboard.com
Sun Jul 14 12:43:07 CEST 2019


Hi Niklas,

On Sun, Jul 14, 2019 at 07:33:06PM +0900, Niklas Söderlund wrote:
> On 2019-07-13 20:23:40 +0300, Laurent Pinchart wrote:
> > When starting the stream on a capture video device it is often needed to
> > queue all the allocated buffers. Add a helper method to do so, and
> > refactor the existing queueBuffer() method to make it clearer.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  src/libcamera/include/v4l2_videodevice.h |  1 +
> >  src/libcamera/pipeline/ipu3/ipu3.cpp     | 13 ++---
> >  src/libcamera/v4l2_videodevice.cpp       | 63 +++++++++++++++++++++---
> >  test/v4l2_videodevice/buffer_sharing.cpp |  8 ++-
> >  test/v4l2_videodevice/capture_async.cpp  |  8 ++-
> >  5 files changed, 69 insertions(+), 24 deletions(-)
> > 
> > diff --git a/src/libcamera/include/v4l2_videodevice.h b/src/libcamera/include/v4l2_videodevice.h
> > index b92df882568f..f948a41fb8c1 100644
> > --- a/src/libcamera/include/v4l2_videodevice.h
> > +++ b/src/libcamera/include/v4l2_videodevice.h
> > @@ -139,6 +139,7 @@ public:
> >  	int releaseBuffers();
> >  
> >  	int queueBuffer(Buffer *buffer);
> > +	int queueAllBuffers(std::vector<std::unique_ptr<Buffer>> *buffers);
> 
> Could this function return the vector instead of taking it as an 
> argument? I think that would make sens as the queueAllBuffers() is an 
> "output" while queueBuffer() is an "input".

I'll do that.

> >  	Signal<Buffer *> bufferReady;
> >  
> >  	int streamOn();
> > diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> > index 1abd20e5fee5..50457891e288 100644
> > --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> > +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> > @@ -131,6 +131,7 @@ public:
> >  	CameraSensor *sensor_;
> >  
> >  	BufferPool pool_;
> > +	std::vector<std::unique_ptr<Buffer>> buffers_;
> >  };
> >  
> >  class IPU3Stream : public Stream
> > @@ -1430,11 +1431,9 @@ int CIO2Device::start()
> >  {
> >  	int ret;
> >  
> > -	for (Buffer &buffer : pool_.buffers()) {
> > -		ret = output_->queueBuffer(&buffer);
> > -		if (ret)
> > -			return ret;
> > -	}
> > +	ret = output_->queueAllBuffers(&buffers_);
> > +	if (ret)
> > +		return ret;
> >  
> >  	ret = output_->streamOn();
> >  	if (ret)
> > @@ -1445,7 +1444,9 @@ int CIO2Device::start()
> >  
> >  int CIO2Device::stop()
> >  {
> > -	return output_->streamOff();
> > +	int ret = output_->streamOff();
> > +	buffers_.clear();
> > +	return ret;
> >  }
> >  
> >  int CIO2Device::mediaBusToFormat(unsigned int code)
> > diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> > index 2d1e87a76c6f..af5ba803de45 100644
> > --- a/src/libcamera/v4l2_videodevice.cpp
> > +++ b/src/libcamera/v4l2_videodevice.cpp
> > @@ -894,8 +894,8 @@ int V4L2VideoDevice::releaseBuffers()
> >   */
> >  int V4L2VideoDevice::queueBuffer(Buffer *buffer)
> >  {
> > +	struct v4l2_plane v4l2Planes[VIDEO_MAX_PLANES] = {};
> >  	struct v4l2_buffer buf = {};
> > -	struct v4l2_plane planes[VIDEO_MAX_PLANES] = {};
> >  	int ret;
> >  
> >  	buf.index = buffer->index();
> > @@ -904,21 +904,20 @@ int V4L2VideoDevice::queueBuffer(Buffer *buffer)
> >  	buf.field = V4L2_FIELD_NONE;
> >  
> >  	bool multiPlanar = V4L2_TYPE_IS_MULTIPLANAR(buf.type);
> > +	const std::vector<Plane> &planes = buffer->planes();
> >  
> >  	if (buf.memory == V4L2_MEMORY_DMABUF) {
> >  		if (multiPlanar) {
> > -			for (unsigned int p = 0;
> > -			     p < buffer->planes().size();
> > -			     p++)
> > -				planes[p].m.fd = buffer->planes()[p].dmabuf();
> > +			for (unsigned int p = 0; p < planes.size(); ++p)
> > +				v4l2Planes[p].m.fd = planes[p].dmabuf();
> >  		} else {
> > -			buf.m.fd = buffer->planes()[0].dmabuf();
> > +			buf.m.fd = planes[0].dmabuf();
> >  		}
> >  	}
> >  
> >  	if (multiPlanar) {
> > -		buf.length = buffer->planes().size();
> > -		buf.m.planes = planes;
> > +		buf.length = planes.size();
> > +		buf.m.planes = v4l2Planes;
> >  	}
> 
> Hum, this seems like an unrelated change which could be in its own 
> commit ;-)

Didn't the commit message mention refactoring queueBuffer() ? :-)

> >  
> >  	if (V4L2_TYPE_IS_OUTPUT(bufferType_)) {
> > @@ -944,6 +943,54 @@ int V4L2VideoDevice::queueBuffer(Buffer *buffer)
> >  	return 0;
> >  }
> >  
> > +/**
> > + * \brief Queue all buffers into the video device
> > + * \param[out] buffers A vector of queued Buffer instances
> > + *
> > + * When starting video capture users of the video device often need to queue
> > + * all allocated buffers to the device. This helper method simplifies the
> > + * implementation of the user by queuing all buffers and populating the
> > + * \a buffers vector with Buffer instances for each queued buffer.
> > + *
> > + * This method is meant to be used with video capture devices internal to a
> > + * pipeline handler, such as ISP statistics capture devices, or raw CSI-2
> > + * receivers. For video capture devices facing applications, buffers shall
> > + * instead be queued when requests are received, and for video output devices,
> > + * buffers shall be queued when frames are ready to be output.
> > + *
> > + * The caller shall ensure that the \a buffers vector remains valid until all
> > + * the queued buffers are dequeued, either during capture, or by stopping the
> > + * video device.
> > + *
> > + * Calling this method on an output device or on a device that has buffers
> > + * already queued is an error and will return -EINVAL.
> > + *
> > + * \return 0 on success or a negative error code otherwise
> > + */
> > +int V4L2VideoDevice::queueAllBuffers(std::vector<std::unique_ptr<Buffer>> *buffers)
> > +{
> > +	int ret;
> > +
> > +	if (queuedBuffersCount_)
> > +		return -EINVAL;
> > +
> > +	if (V4L2_TYPE_IS_OUTPUT(bufferType_))
> > +		return -EINVAL;
> > +
> > +	buffers->clear();
> > +
> > +	for (unsigned int i = 0; i < bufferPool_->count(); ++i) {
> > +		Buffer *buffer = new Buffer();
> > +		buffer->index_ = i;
> > +		buffers->emplace_back(buffer);
> > +		ret = queueBuffer(buffer);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  /**
> >   * \brief Dequeue the next available buffer from the video device
> >   *
> > diff --git a/test/v4l2_videodevice/buffer_sharing.cpp b/test/v4l2_videodevice/buffer_sharing.cpp
> > index cc724b226619..459bd238fe97 100644
> > --- a/test/v4l2_videodevice/buffer_sharing.cpp
> > +++ b/test/v4l2_videodevice/buffer_sharing.cpp
> > @@ -117,11 +117,9 @@ protected:
> >  		capture_->bufferReady.connect(this, &BufferSharingTest::captureBufferReady);
> >  		output_->bufferReady.connect(this, &BufferSharingTest::outputBufferReady);
> >  
> > -		/* Queue all the buffers to the capture device. */
> > -		for (Buffer &buffer : pool_.buffers()) {
> > -			if (capture_->queueBuffer(&buffer))
> > -				return TestFail;
> > -		}
> > +		std::vector<std::unique_ptr<Buffer>> buffers;
> > +		if (capture_->queueAllBuffers(&buffers))
> > +			return TestFail;
> >  
> >  		ret = capture_->streamOn();
> >  		if (ret) {
> > diff --git a/test/v4l2_videodevice/capture_async.cpp b/test/v4l2_videodevice/capture_async.cpp
> > index cea4fffbf7a5..c6d6ec6b74bd 100644
> > --- a/test/v4l2_videodevice/capture_async.cpp
> > +++ b/test/v4l2_videodevice/capture_async.cpp
> > @@ -46,11 +46,9 @@ protected:
> >  
> >  		capture_->bufferReady.connect(this, &CaptureAsyncTest::receiveBuffer);
> >  
> > -		/* Queue all the buffers to the device. */
> > -		for (Buffer &b : pool_.buffers()) {
> > -			if (capture_->queueBuffer(&b))
> > -				return TestFail;
> > -		}
> > +		std::vector<std::unique_ptr<Buffer>> buffers;
> > +		if (capture_->queueAllBuffers(&buffers))
> > +			return TestFail;
> >  
> >  		ret = capture_->streamOn();
> >  		if (ret)
> > -- 
> > Regards,
> > 
> > Laurent Pinchart
> > 
> > _______________________________________________
> > libcamera-devel mailing list
> > libcamera-devel at lists.libcamera.org
> > https://lists.libcamera.org/listinfo/libcamera-devel
> 
> -- 
> Regards,
> Niklas Söderlund

-- 
Regards,

Laurent Pinchart


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