[libcamera-devel] [PATCH 1/9] libcamera: stream: Provide accessors to buffers
Niklas Söderlund
niklas.soderlund at ragnatech.se
Sat Jul 6 13:34:18 CEST 2019
Hi Jacopo,
Thanks for your work.
On 2019-07-05 00:53:26 +0200, Jacopo Mondi wrote:
> All interactions with the Stream's buffers currently go through the
> BufferPool. In order to shorten accessing the buffers array, and
> restrict access to the Stream's internal buffer pool, provide operations
> to access the buffers, create and destroy them.
>
> It is still possible to access the pool for pipeline handlers to
> populate it by exporting buffers from a video device to the pool.
>
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
> include/libcamera/stream.h | 12 ++++++++++
> src/cam/capture.cpp | 4 ++--
> src/libcamera/camera.cpp | 6 ++---
> src/libcamera/pipeline/ipu3/ipu3.cpp | 4 ++--
> src/libcamera/stream.cpp | 35 ++++++++++++++++++++++++++++
> src/qcam/main_window.cpp | 4 +---
> test/camera/capture.cpp | 3 +--
> test/camera/statemachine.cpp | 3 +--
> 8 files changed, 57 insertions(+), 14 deletions(-)
>
> diff --git a/include/libcamera/stream.h b/include/libcamera/stream.h
> index 5b4fea324ce4..fa7d6ba4987c 100644
> --- a/include/libcamera/stream.h
> +++ b/include/libcamera/stream.h
> @@ -66,12 +66,24 @@ class Stream
> {
> public:
> Stream();
> + /*
> + * FIXME:
> + * If I could find a way to export buffers in pipeline handlers
> + * without accessing the pool with
> + * video_->exportBuffers(&stream->bufferPool());
> + * we could remove access to the internal pool completely.
> + */
> BufferPool &bufferPool() { return bufferPool_; }
> + std::vector<Buffer> &buffers() { return bufferPool_.buffers(); }
> + unsigned int bufferCount() const { return bufferPool_.count(); }
I commented on this in v2 and you replied to that and then I dropped the
ball, sorry about. I will cite your reply to v2 here and then reply to
it.
My comment was about the possibility to add to address the FIXME.
int importBuffers(V4L2VideoDevice *video)
{
return video->exportBuffers(&bufferPool());
}
You replied:
int Stream::importBuffers() you mean ? I considered that, but to me
what happen is that "the memory reserved in the video device is made
accessible to the Stream", so I would either use export or even map
as verbs. Import is not nice if you ask me, as it might overlap with the
'importing external buffers' idea. What do you think?
Yes as Stream::importBuffers() :-) I have no strong opinion on the name
of the function. My view however that the function name should try to
describe how it operates on the object it's connected to. So in this
case importBuffers() make sens to me, as the Stream will import buffers
from the V4L2 video device.
> const StreamConfiguration &configuration() const { return configuration_; }
>
> protected:
> friend class Camera;
>
> + void createBuffers(unsigned int count);
> + void destroyBuffers();
> +
> BufferPool bufferPool_;
> StreamConfiguration configuration_;
> };
> diff --git a/src/cam/capture.cpp b/src/cam/capture.cpp
> index 6b842d73390d..1bcc9c7e9cf4 100644
> --- a/src/cam/capture.cpp
> +++ b/src/cam/capture.cpp
> @@ -76,7 +76,7 @@ int Capture::capture(EventLoop *loop)
> unsigned int nbuffers = UINT_MAX;
> for (StreamConfiguration &cfg : *config_) {
> Stream *stream = cfg.stream();
> - nbuffers = std::min(nbuffers, stream->bufferPool().count());
> + nbuffers = std::min(nbuffers, stream->bufferCount());
> }
>
> /*
> @@ -95,7 +95,7 @@ int Capture::capture(EventLoop *loop)
> std::map<Stream *, Buffer *> map;
> for (StreamConfiguration &cfg : *config_) {
> Stream *stream = cfg.stream();
> - map[stream] = &stream->bufferPool().buffers()[i];
> + map[stream] = &stream->buffers()[i];
> }
>
> ret = request->setBuffers(map);
> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> index 592dfd39eacc..088a39623e36 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -683,7 +683,7 @@ int Camera::configure(CameraConfiguration *config)
> * Allocate buffer objects in the pool.
> * Memory will be allocated and assigned later.
> */
> - stream->bufferPool().createBuffers(cfg.bufferCount);
> + stream->createBuffers(cfg.bufferCount);
> }
>
> state_ = CameraConfigured;
> @@ -740,14 +740,14 @@ int Camera::freeBuffers()
> return -EACCES;
>
> for (Stream *stream : activeStreams_) {
> - if (!stream->bufferPool().count())
> + if (!stream->bufferCount())
> continue;
>
> /*
> * All mappings must be destroyed before buffers can be freed
> * by the V4L2 device that has allocated them.
> */
> - stream->bufferPool().destroyBuffers();
> + stream->destroyBuffers();
> }
>
> state_ = CameraConfigured;
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index e4efb9722f76..2de0892138a8 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -634,7 +634,7 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
> * of buffers as the active ones.
> */
> if (!outStream->active_) {
> - bufferCount = vfStream->bufferPool().count();
> + bufferCount = vfStream->bufferCount();
> outStream->device_->pool->createBuffers(bufferCount);
> ret = imgu->exportBuffers(outStream->device_,
> outStream->device_->pool);
> @@ -643,7 +643,7 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
> }
>
> if (!vfStream->active_) {
> - bufferCount = outStream->bufferPool().count();
> + bufferCount = outStream->bufferCount();
> vfStream->device_->pool->createBuffers(bufferCount);
> ret = imgu->exportBuffers(vfStream->device_,
> vfStream->device_->pool);
> diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
> index d8e87c62281c..35197be09c26 100644
> --- a/src/libcamera/stream.cpp
> +++ b/src/libcamera/stream.cpp
> @@ -418,12 +418,47 @@ Stream::Stream()
> * \return A reference to the buffer pool
> */
>
> +/**
> + * \fn Stream::buffers()
> + * \brief Retrieve the stream's buffers
> + * \return The list of stream's buffers
> + */
> +
> +/**
> + * \fn Stream::bufferCount()
> + * \brief Retrieve the number of buffers in the stream
> + * \return The number of stream buffers
> + */
> +
> /**
> * \fn Stream::configuration()
> * \brief Retrieve the active configuration of the stream
> * \return The active configuration of the stream
> */
>
> +/**
> + * \brief Create buffers for the stream
> + * \param count The number of buffers to create
> + *
> + * Create \a count empty buffers in the Stream's buffer pool.
> + */
> +void Stream::createBuffers(unsigned int count)
> +{
> + destroyBuffers();
> + if (count == 0)
> + return;
> +
> + bufferPool_.createBuffers(count);
> +}
> +
> +/**
> + * \brief Destroy buffers in the stream
> + */
> +void Stream::destroyBuffers()
> +{
> + bufferPool_.destroyBuffers();
> +}
> +
> /**
> * \var Stream::bufferPool_
> * \brief The pool of buffers associated with the stream
> diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
> index 16b123132dd9..a0703b322c16 100644
> --- a/src/qcam/main_window.cpp
> +++ b/src/qcam/main_window.cpp
> @@ -122,10 +122,8 @@ int MainWindow::startCapture()
> return ret;
> }
>
> - BufferPool &pool = stream->bufferPool();
> std::vector<Request *> requests;
> -
> - for (Buffer &buffer : pool.buffers()) {
> + for (Buffer &buffer : stream->buffers()) {
> Request *request = camera_->createRequest();
> if (!request) {
> std::cerr << "Can't create request" << std::endl;
> diff --git a/test/camera/capture.cpp b/test/camera/capture.cpp
> index 7ce247cc482d..a0385ec2c74d 100644
> --- a/test/camera/capture.cpp
> +++ b/test/camera/capture.cpp
> @@ -76,9 +76,8 @@ protected:
> }
>
> Stream *stream = cfg.stream();
> - BufferPool &pool = stream->bufferPool();
> std::vector<Request *> requests;
> - for (Buffer &buffer : pool.buffers()) {
> + for (Buffer &buffer : stream->buffers()) {
> Request *request = camera_->createRequest();
> if (!request) {
> cout << "Failed to create request" << endl;
> diff --git a/test/camera/statemachine.cpp b/test/camera/statemachine.cpp
> index 84d2a6fab5f0..c23455b5bb21 100644
> --- a/test/camera/statemachine.cpp
> +++ b/test/camera/statemachine.cpp
> @@ -211,8 +211,7 @@ protected:
> return TestFail;
>
> Stream *stream = *camera_->streams().begin();
> - BufferPool &pool = stream->bufferPool();
> - Buffer &buffer = pool.buffers().front();
> + Buffer &buffer = stream->buffers().front();
> std::map<Stream *, Buffer *> map = { { stream, &buffer } };
> if (request->setBuffers(map))
> return TestFail;
> --
> 2.21.0
>
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--
Regards,
Niklas Söderlund
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