[libcamera-devel] [PATCH v4 6/9] libcamera: pipeline: raspberrypi: Rework stream buffer logic for zero-copy

Laurent Pinchart laurent.pinchart at ideasonboard.com
Wed Jul 22 17:48:27 CEST 2020


Hi Naush,

On Wed, Jul 22, 2020 at 04:33:08PM +0100, Naushir Patuck wrote:
> On Wed, 22 Jul 2020 at 16:25, Laurent Pinchart wrote:
> > On Wed, Jul 22, 2020 at 01:21:33PM +0100, Kieran Bingham wrote:
> >> On 22/07/2020 09:04, Naushir Patuck wrote:
> >>> On Tue, 21 Jul 2020 at 16:41, Kieran Bingham wrote:
> >>>> On 20/07/2020 10:13, Naushir Patuck wrote:
> >>>>> Stop using v4l2_videodevice::allocateBuffer() for internal buffers and
> >>>>> instead export/import all buffers. This allows the pipeline to return
> >>>>> any stream buffer requested by the application as zero-copy.
> >>>>>
> >>>>> Advertise the Unicam Image stream as the RAW capture stream now.
> >>>>>
> >>>>> The RPiStream object now maintains a new list of buffers that are
> >>>>> available to queue into a device. This is needed to distinguish between
> >>>>> FrameBuffers allocated for internal use vs externally provided buffers.
> >>>>> When a Request comes in, if a buffer is not provided for an exported
> >>>>> stream, we re-use a buffer from this list.
> >>>>>
> >>>>> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> >>>>> Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> >>>>
> >>>> A few small nit fixups below but they could possibly be fixed while
> >>>> applying anyway if you prefer.
> >>>>
> >>>> I've hit review fatigue though, so I'll look at this again tomorrow.
> >>>
> >>> I understand :)
> >>> I will make the necessary fixups based on your review comments, and
> >>> submit a new patch set.  Will wait until you have finished reviewing
> >>> this one before I send the next revision.
> >>
> >> Looking good, I think the only actionable thing remaining here is
> >> potentially to use ASSERT() over assert() :-)
> >>
> >>>>> ---
> >>>>>  .../pipeline/raspberrypi/raspberrypi.cpp      | 228 ++++++++++--------
> >>>>>  .../pipeline/raspberrypi/rpi_stream.cpp       | 122 +++++++---
> >>>>>  .../pipeline/raspberrypi/rpi_stream.h         |  30 ++-
> >>>>>  3 files changed, 226 insertions(+), 154 deletions(-)
> >>>>>
> >>>>> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> >>>>> index 8f6a999b..dbc22521 100644
> >>>>> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> >>>>> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> >>>>> @@ -187,7 +187,8 @@ private:
> >>>>>       void checkRequestCompleted();
> >>>>>       void tryRunPipeline();
> >>>>>       void tryFlushQueues();
> >>>>> -     FrameBuffer *updateQueue(std::queue<FrameBuffer *> &q, uint64_t timestamp, V4L2VideoDevice *dev);
> >>>>> +     FrameBuffer *updateQueue(std::queue<FrameBuffer *> &q, uint64_t timestamp,
> >>>>> +                              RPi::RPiStream *stream);
> >>>>>
> >>>>>       unsigned int ispOutputCount_;
> >>>>>  };
> >>>>> @@ -508,8 +509,15 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
> >>>>>               StreamConfiguration &cfg = config->at(i);
> >>>>>
> >>>>>               if (isRaw(cfg.pixelFormat)) {
> >>>>> -                     cfg.setStream(&data->isp_[Isp::Input]);
> >>>>> -                     data->isp_[Isp::Input].setExternal(true);
> >>>>> +                     cfg.setStream(&data->unicam_[Unicam::Image]);
> >>>>> +                     /*
> >>>>> +                      * We must set both Unicam streams as external, even
> >>>>> +                      * though the application may only request RAW frames.
> >>>>> +                      * This is because we match timestamps on both streams
> >>>>> +                      * to synchronise buffers.
> >>>>> +                      */
> >>>>> +                     data->unicam_[Unicam::Image].setExternal(true);
> >>>>> +                     data->unicam_[Unicam::Embedded].setExternal(true);
> >>>>>                       continue;
> >>>>>               }
> >>>>>
> >>>>> @@ -612,7 +620,7 @@ int PipelineHandlerRPi::exportFrameBuffers(Camera *camera, Stream *stream,
> >>>>>       unsigned int count = stream->configuration().bufferCount;
> >>>>>       int ret = s->dev()->exportBuffers(count, buffers);
> >>>>>
> >>>>> -     s->setExternalBuffers(buffers);
> >>>>> +     s->setExportedBuffers(buffers);
> >>>>>
> >>>>>       return ret;
> >>>>>  }
> >>>>> @@ -712,14 +720,23 @@ int PipelineHandlerRPi::queueRequestDevice(Camera *camera, Request *request)
> >>>>>       if (data->state_ == RPiCameraData::State::Stopped)
> >>>>>               return -EINVAL;
> >>>>>
> >>>>> -     /* Ensure all external streams have associated buffers! */
> >>>>> -     for (auto &stream : data->isp_) {
> >>>>> -             if (!stream.isExternal())
> >>>>> -                     continue;
> >>>>> +     LOG(RPI, Debug) << "queueRequestDevice: New request.";
> >>>>>
> >>>>> -             if (!request->findBuffer(&stream)) {
> >>>>> -                     LOG(RPI, Error) << "Attempt to queue request with invalid stream.";
> >>>>> -                     return -ENOENT;
> >>>>> +     /* Push all buffers supplied in the Request to the respective streams. */
> >>>>> +     for (auto stream : data->streams_) {
> >>>>> +             if (stream->isExternal()) {
> >>>>
> >>>> Are all streams now 'external' ?
> >>>
> >>> All streams but the ISP input (which only imports buffers) *can* be
> >>> external.  They are marked external only if the app configures the
> >>> pipeline handler by saying it may request a buffer from the stream.
> >>> In reality, all streams could be marked external all the time, but the
> >>> buffer handling will take a slightly less efficient path, so I kept
> >>> the distinction.
> >>>
> >>>>> +                     FrameBuffer *buffer = request->findBuffer(stream);
> >>>>> +                     /*
> >>>>> +                      * A nullptr in buffer means that we should queue an internally
> >>>>> +                      * allocated buffer.
> >>
> >> Now I understand what's going on here, perhaps this could be expanded a
> >> bit to explain?
> >>
> >> "If no buffer is provided by the request for this stream, we queue a
> >> nullptr to the stream to signify that it must use an internally
> >> allocated buffer for this capture request which will not be given back
> >> to the application, but can be used to support the internal pipeline flow."
> >>
> >> Now I see how this leads towards zero-copy raw support ;-)
> >>
> >>>>> +                      *
> >>>>> +                      * The below queueBuffer() call will do nothing if there are not
> >>>>> +                      * enough internal buffers allocated, but this will be handled by
> >>>>> +                      * queuing the request for buffers in the RPiStream object.
> >>>>> +                      */
> >>>>> +                     int ret = stream->queueBuffer(buffer);
> >>>>> +                     if (ret)
> >>>>> +                             return ret;
> >>>>>               }
> >>>>>       }
> >>>>>
> >>>>> @@ -808,12 +825,10 @@ bool PipelineHandlerRPi::match(DeviceEnumerator *enumerator)
> >>>>>       /* Initialize the camera properties. */
> >>>>>       data->properties_ = data->sensor_->properties();
> >>>>>
> >>>>> -     /*
> >>>>> -      * List the available output streams.
> >>>>> -      * Currently cannot do Unicam streams!
> >>>>> -      */
> >>>>> +     /*List the available streams an application may request. */
> >>>>
> >>>> Minor nit, there's a space missing between /* and List ...
> >>>>
> >>>>>       std::set<Stream *> streams;
> >>>>> -     streams.insert(&data->isp_[Isp::Input]);
> >>>>> +     streams.insert(&data->unicam_[Unicam::Image]);
> >>>>> +     streams.insert(&data->unicam_[Unicam::Embedded]);
> >
> > Can an application request the embedded data ?
> 
> With this change, we can now advertise embedded data as well as isp
> statistics available for the application to request.  The only thing
> missing is a way for the application to do so.

Could we avoid exposing non-image streams to applications in the
meantime though ?

> In a separate discussion we talked about libcamera::PixelFormat not
> being the right place as these are data formats, not image formats.
> No conclusion has been reached yet, but I will resurrect that
> discussion shortly :-)

Take your time :-) Jokes aside, I'm working on support for
memory-to-memory processing (a.k.a. reprocessing), and I think that
should be merged first as a base to provide statistics to applications.
I expect it will take at least a couple of months until the reprocessing
API is ready, so there's no hurry at all.

> >>>>>       streams.insert(&data->isp_[Isp::Output0]);
> >>>>>       streams.insert(&data->isp_[Isp::Output1]);
> >>>>>       streams.insert(&data->isp_[Isp::Stats]);
> >>>>> @@ -831,9 +846,28 @@ int PipelineHandlerRPi::queueAllBuffers(Camera *camera)
> >>>>>       int ret;
> >>>>>
> >>>>>       for (auto const stream : data->streams_) {
> >>>>> -             ret = stream->queueBuffers();
> >>>>> -             if (ret < 0)
> >>>>> -                     return ret;
> >>>>> +             if (!stream->isExternal()) {
> >>>>> +                     ret = stream->queueAllBuffers();
> >>>>> +                     if (ret < 0)
> >>>>> +                             return ret;
> >>>>> +             } else {
> >>>>> +                     /*
> >>>>> +                      * For external streams, we must queue up a set of internal
> >>>>> +                      * buffers to handle the number of drop frames requested by
> >>>>> +                      * the IPA. This is done by passing nullptr in queueBuffer().
> >>>>> +                      *
> >>>>> +                      * The below queueBuffer() call will do nothing if there
> >>>>> +                      * are not enough internal buffers allocated, but this will
> >>>>> +                      * be handled by queuing the request for buffers in the
> >>>>> +                      * RPiStream object.
> >>>>> +                      */
> >>>>> +                     unsigned int i;
> >>>>> +                     for (i = 0; i < data->dropFrameCount_; i++) {
> >>>>> +                             int ret = stream->queueBuffer(nullptr);
> >>>>> +                             if (ret)
> >>>>> +                                     return ret;
> >>>>> +                     }
> >>>>> +             }
> >>>>>       }
> >>>>>
> >>>>>       return 0;
> >>>>> @@ -847,7 +881,8 @@ int PipelineHandlerRPi::prepareBuffers(Camera *camera)
> >>>>>       /*
> >>>>>        * Decide how many internal buffers to allocate. For now, simply look
> >>>>>        * at how many external buffers will be provided. Will need to improve
> >>>>> -      * this logic.
> >>>>> +      * this logic. However, we really must have all stream allocate the same
> >>>>
> >>>> s/stream/streams/
> >>>>
> >>>>> +      * number of buffers to simplify error handling in queueRequestDevice().
> >>>>>        */
> >>>>
> >>>> Does this include Raw streams? I thought that allocates less buffers? Or
> >>>> perhaps it's the same number of internal buffers, and only 2 extra
> >>>> external buffers for that case...
> >>>
> >>> That's correct.  For now all (including Raw) streams allocate the same
> >>> number of internal buffers.  Hence the comment that we could improve
> >>> this logic, it is a bit wasteful on memory.  This bit does need
> >>> refinement at some point.
> >>>
> >>>>>       unsigned int maxBuffers = 0;
> >>>>>       for (const Stream *s : camera->streams())
> >>>>> @@ -855,33 +890,9 @@ int PipelineHandlerRPi::prepareBuffers(Camera *camera)
> >>>>>                       maxBuffers = std::max(maxBuffers, s->configuration().bufferCount);
> >>>>>
> >>>>>       for (auto const stream : data->streams_) {
> >>>>> -             if (stream->isExternal() || stream->isImporter()) {
> >>>>> -                     /*
> >>>>> -                      * If a stream is marked as external reserve memory to
> >>>>> -                      * prepare to import as many buffers are requested in
> >>>>> -                      * the stream configuration.
> >>>>> -                      *
> >>>>> -                      * If a stream is an internal stream with importer
> >>>>> -                      * role, reserve as many buffers as possible.
> >>>>> -                      */
> >>>>> -                     unsigned int count = stream->isExternal()
> >>>>> -                                                  ? stream->configuration().bufferCount
> >>>>> -                                                  : maxBuffers;
> >>>>> -                     ret = stream->importBuffers(count);
> >>>>> -                     if (ret < 0)
> >>>>> -                             return ret;
> >>>>> -             } else {
> >>>>> -                     /*
> >>>>> -                      * If the stream is an internal exporter allocate and
> >>>>> -                      * export as many buffers as possible to its internal
> >>>>> -                      * pool.
> >>>>> -                      */
> >>>>> -                     ret = stream->allocateBuffers(maxBuffers);
> >>>>> -                     if (ret < 0) {
> >>>>> -                             freeBuffers(camera);
> >>>>> -                             return ret;
> >>>>> -                     }
> >>>>> -             }
> >>>>> +             ret = stream->prepareBuffers(maxBuffers);
> >>>>> +             if (ret < 0)
> >>>>> +                     return ret;
> >
> > This doesn't free buffers anymore on failure, is that an oversight ?
> 
> Oversight.  Will fix.
> 
> >
> >>>>>       }
> >>>>>
> >>>>>       /*
> >>>>> @@ -889,7 +900,7 @@ int PipelineHandlerRPi::prepareBuffers(Camera *camera)
> >>>>>        * the IPA and RPI_IPA_EVENT_SIGNAL_ISP_PREPARE event.
> >>>>>        */
> >>>>>       count = 0;
> >>>>> -     for (auto const &b : *data->unicam_[Unicam::Image].getBuffers()) {
> >>>>> +     for (auto const &b : data->unicam_[Unicam::Image].getBuffers()) {
> >>>>>               b->setCookie(count++);
> >>>>>       }
> >>>>>
> >>>>> @@ -898,14 +909,14 @@ int PipelineHandlerRPi::prepareBuffers(Camera *camera)
> >>>>>        * the IPA.
> >>>>>        */
> >>>>>       count = 0;
> >>>>> -     for (auto const &b : *data->isp_[Isp::Stats].getBuffers()) {
> >>>>> +     for (auto const &b : data->isp_[Isp::Stats].getBuffers()) {
> >>>>>               b->setCookie(count++);
> >>>>>               data->ipaBuffers_.push_back({ .id = RPiIpaMask::STATS | b->cookie(),
> >>>>>                                             .planes = b->planes() });
> >>>>>       }
> >>>>>
> >>>>>       count = 0;
> >>>>> -     for (auto const &b : *data->unicam_[Unicam::Embedded].getBuffers()) {
> >>>>> +     for (auto const &b : data->unicam_[Unicam::Embedded].getBuffers()) {
> >>>>>               b->setCookie(count++);
> >>>>>               data->ipaBuffers_.push_back({ .id = RPiIpaMask::EMBEDDED_DATA | b->cookie(),
> >>>>>                                             .planes = b->planes() });
> >>>>> @@ -1066,7 +1077,7 @@ void RPiCameraData::queueFrameAction(unsigned int frame, const IPAOperationData
> >>>>>       switch (action.operation) {
> >>>>>       case RPI_IPA_ACTION_STATS_METADATA_COMPLETE: {
> >>>>>               unsigned int bufferId = action.data[0];
> >>>>> -             FrameBuffer *buffer = isp_[Isp::Stats].getBuffers()->at(bufferId).get();
> >>>>> +             FrameBuffer *buffer = isp_[Isp::Stats].getBuffers().at(bufferId);
> >>>>>
> >>>>>               handleStreamBuffer(buffer, &isp_[Isp::Stats]);
> >>>>>               /* Fill the Request metadata buffer with what the IPA has provided */
> >>>>> @@ -1077,19 +1088,19 @@ void RPiCameraData::queueFrameAction(unsigned int frame, const IPAOperationData
> >>>>>
> >>>>>       case RPI_IPA_ACTION_EMBEDDED_COMPLETE: {
> >>>>>               unsigned int bufferId = action.data[0];
> >>>>> -             FrameBuffer *buffer = unicam_[Unicam::Embedded].getBuffers()->at(bufferId).get();
> >>>>> +             FrameBuffer *buffer = unicam_[Unicam::Embedded].getBuffers().at(bufferId);
> >>>>>               handleStreamBuffer(buffer, &unicam_[Unicam::Embedded]);
> >>>>>               break;
> >>>>>       }
> >>>>>
> >>>>>       case RPI_IPA_ACTION_RUN_ISP: {
> >>>>>               unsigned int bufferId = action.data[0];
> >>>>> -             FrameBuffer *buffer = unicam_[Unicam::Image].getBuffers()->at(bufferId).get();
> >>>>> +             FrameBuffer *buffer = unicam_[Unicam::Image].getBuffers().at(bufferId);
> >>>>>
> >>>>>               LOG(RPI, Debug) << "Input re-queue to ISP, buffer id " << buffer->cookie()
> >>>>>                               << ", timestamp: " << buffer->metadata().timestamp;
> >>>>>
> >>>>> -             isp_[Isp::Input].dev()->queueBuffer(buffer);
> >>>>> +             isp_[Isp::Input].queueBuffer(buffer);
> >>>>>               ispOutputCount_ = 0;
> >>>>>               break;
> >>>>>       }
> >>>>> @@ -1190,22 +1201,27 @@ void RPiCameraData::ispOutputDequeue(FrameBuffer *buffer)
> >>>>>                       << ", buffer id " << buffer->cookie()
> >>>>>                       << ", timestamp: " << buffer->metadata().timestamp;
> >>>>>
> >>>>> -     handleStreamBuffer(buffer, stream);
> >>>>> -
> >>>>>       /*
> >>>>> -      * Increment the number of ISP outputs generated.
> >>>>> -      * This is needed to track dropped frames.
> >>>>> +      * ISP statistics buffer must not be re-queued or sent back to the
> >>>>> +      * application until after the IPA signals so.
> >>>>>        */
> >>>>> -     ispOutputCount_++;
> >>>>> -
> >>>>> -     /* If this is a stats output, hand it to the IPA now. */
> >>>>>       if (stream == &isp_[Isp::Stats]) {
> >>>>>               IPAOperationData op;
> >>>>>               op.operation = RPI_IPA_EVENT_SIGNAL_STAT_READY;
> >>>>>               op.data = { RPiIpaMask::STATS | buffer->cookie() };
> >>>>>               ipa_->processEvent(op);
> >>>>> +     } else {
> >>>>> +             /* Any other ISP output can be handed back to the application now. */
> >>>>> +             handleStreamBuffer(buffer, stream);
> >>>>>       }
> >>>>>
> >>>>> +     /*
> >>>>> +      * Increment the number of ISP outputs generated.
> >>>>> +      * This is needed to track dropped frames.
> >>>>> +      */
> >>>>> +     ispOutputCount_++;
> >>>>> +
> >>>>> +
> >
> > Extra blank line ?
> >
> >>>>>       handleState();
> >>>>>  }
> >>>>>
> >>>>> @@ -1218,8 +1234,12 @@ void RPiCameraData::clearIncompleteRequests()
> >>>>>        */
> >>>>>       for (auto const request : requestQueue_) {
> >>>>>               for (auto const stream : streams_) {
> >>>>> -                     if (stream->isExternal())
> >>>>> -                             stream->dev()->queueBuffer(request->findBuffer(stream));
> >>>>> +                     if (!stream->isExternal())
> >>>>> +                             continue;
> >>>>> +
> >>>>> +                     FrameBuffer *buffer = request->findBuffer(stream);
> >>>>> +                     if (buffer)
> >>>>> +                             stream->queueBuffer(buffer);
> >>>>>               }
> >>>>>       }
> >>>>>
> >>>>> @@ -1248,7 +1268,7 @@ void RPiCameraData::clearIncompleteRequests()
> >>>>>                        * Has the buffer already been handed back to the
> >>>>>                        * request? If not, do so now.
> >>>>>                        */
> >>>>> -                     if (buffer->request())
> >>>>> +                     if (buffer && buffer->request())
> >>>>>                               pipe_->completeBuffer(camera_, request, buffer);
> >>>>>               }
> >>>>>
> >>>>> @@ -1260,30 +1280,24 @@ void RPiCameraData::clearIncompleteRequests()
> >>>>>  void RPiCameraData::handleStreamBuffer(FrameBuffer *buffer, RPi::RPiStream *stream)
> >>>>>  {
> >>>>>       if (stream->isExternal()) {
> >>>>> -             if (!dropFrameCount_) {
> >>>>> -                     Request *request = buffer->request();
> >>>>> +             Request *request = requestQueue_.front();
> >>>>> +
> >>>>> +             if (!dropFrameCount_ && request->findBuffer(stream) == buffer) {
> >>>>> +                     /*
> >>>>> +                      * Tag the buffer as completed, returning it to the
> >>>>> +                      * application.
> >>>>> +                      */
> >>>>>                       pipe_->completeBuffer(camera_, request, buffer);
> >>>>> +             } else {
> >>>>> +                     /*
> >>>>> +                      * This buffer was not part of the Request, so we can
> >>>>> +                      * recycle it.
> >>>>> +                      */
> >>>>> +                     stream->returnBuffer(buffer);
> >>>>>               }
> >>>>>       } else {
> >>>>> -             /* Special handling for RAW buffer Requests.
> >>>>> -              *
> >>>>> -              * The ISP input stream is alway an import stream, but if the
> >>>>> -              * current Request has been made for a buffer on the stream,
> >>>>> -              * simply memcpy to the Request buffer and requeue back to the
> >>>>> -              * device.
> >>>>> -              */
> >>>>> -             if (stream == &unicam_[Unicam::Image] && !dropFrameCount_) {
> >>>>> -                     const Stream *rawStream = static_cast<const Stream *>(&isp_[Isp::Input]);
> >>>>> -                     Request *request = requestQueue_.front();
> >>>>> -                     FrameBuffer *raw = request->findBuffer(const_cast<Stream *>(rawStream));
> >>>>> -                     if (raw) {
> >>>>> -                             raw->copyFrom(buffer);
> >>>>> -                             pipe_->completeBuffer(camera_, request, raw);
> >>>>> -                     }
> >>>>> -             }
> >>>>> -
> >>>>> -             /* Simply requeue the buffer. */
> >>>>> -             stream->dev()->queueBuffer(buffer);
> >>>>> +             /* Simply re-queue the buffer to the requested stream. */
> >>>>> +             stream->queueBuffer(buffer);
> >>>>>       }
> >>>>>  }
> >>>>>
> >>>>> @@ -1367,7 +1381,7 @@ void RPiCameraData::tryRunPipeline()
> >>>>>        * current bayer buffer will be removed and re-queued to the driver.
> >>>>>        */
> >>>>>       embeddedBuffer = updateQueue(embeddedQueue_, bayerBuffer->metadata().timestamp,
> >>>>> -                                  unicam_[Unicam::Embedded].dev());
> >>>>> +                                  &unicam_[Unicam::Embedded]);
> >>>>>
> >>>>>       if (!embeddedBuffer) {
> >>>>>               LOG(RPI, Debug) << "Could not find matching embedded buffer";
> >>>>> @@ -1386,7 +1400,7 @@ void RPiCameraData::tryRunPipeline()
> >>>>>
> >>>>>               embeddedBuffer = embeddedQueue_.front();
> >>>>>               bayerBuffer = updateQueue(bayerQueue_, embeddedBuffer->metadata().timestamp,
> >>>>> -                                       unicam_[Unicam::Image].dev());
> >>>>> +                                       &unicam_[Unicam::Image]);
> >>>>>
> >>>>>               if (!bayerBuffer) {
> >>>>>                       LOG(RPI, Debug) << "Could not find matching bayer buffer - ending.";
> >>>>> @@ -1394,11 +1408,7 @@ void RPiCameraData::tryRunPipeline()
> >>>>>               }
> >>>>>       }
> >>>>>
> >>>>> -     /*
> >>>>> -      * Take the first request from the queue and action the IPA.
> >>>>> -      * Unicam buffers for the request have already been queued as they come
> >>>>> -      * in.
> >>>>> -      */
> >>>>> +     /* Take the first request from the queue and action the IPA. */
> >>>>>       Request *request = requestQueue_.front();
> >>>>>
> >>>>>       /*
> >>>>> @@ -1410,12 +1420,6 @@ void RPiCameraData::tryRunPipeline()
> >>>>>       op.controls = { request->controls() };
> >>>>>       ipa_->processEvent(op);
> >>>>>
> >>>>> -     /* Queue up any ISP buffers passed into the request. */
> >>>>> -     for (auto &stream : isp_) {
> >>>>> -             if (stream.isExternal())
> >>>>> -                     stream.dev()->queueBuffer(request->findBuffer(&stream));
> >>>>> -     }
> >>>>> -
> >>>>>       /* Ready to use the buffers, pop them off the queue. */
> >>>>>       bayerQueue_.pop();
> >>>>>       embeddedQueue_.pop();
> >>>>> @@ -1445,32 +1449,42 @@ void RPiCameraData::tryFlushQueues()
> >>>>>        * and give a chance for the hardware to return to lock-step. We do have
> >>>>>        * to drop all interim frames.
> >>>>>        */
> >>>>> -     if (unicam_[Unicam::Image].getBuffers()->size() == bayerQueue_.size() &&
> >>>>> -         unicam_[Unicam::Embedded].getBuffers()->size() == embeddedQueue_.size()) {
> >>>>> +     if (unicam_[Unicam::Image].getBuffers().size() == bayerQueue_.size() &&
> >>>>> +         unicam_[Unicam::Embedded].getBuffers().size() == embeddedQueue_.size()) {
> >>>>> +             /* This cannot happen when Unicam streams are external. */
> >>>>> +             assert(!unicam_[Unicam::Image].isExternal());
> >>>>> +
> >>>>>               LOG(RPI, Warning) << "Flushing all buffer queues!";
> >>>>>
> >>>>>               while (!bayerQueue_.empty()) {
> >>>>> -                     unicam_[Unicam::Image].dev()->queueBuffer(bayerQueue_.front());
> >>>>> +                     unicam_[Unicam::Image].queueBuffer(bayerQueue_.front());
> >>>>>                       bayerQueue_.pop();
> >>>>>               }
> >>>>>
> >>>>>               while (!embeddedQueue_.empty()) {
> >>>>> -                     unicam_[Unicam::Embedded].dev()->queueBuffer(embeddedQueue_.front());
> >>>>> +                     unicam_[Unicam::Embedded].queueBuffer(embeddedQueue_.front());
> >>>>>                       embeddedQueue_.pop();
> >>>>>               }
> >>>>>       }
> >>>>>  }
> >>>>>
> >>>>>  FrameBuffer *RPiCameraData::updateQueue(std::queue<FrameBuffer *> &q, uint64_t timestamp,
> >>>>> -                                     V4L2VideoDevice *dev)
> >>>>> +                                     RPi::RPiStream *stream)
> >>>>>  {
> >>>>> +     /*
> >>>>> +      * If the unicam streams are external (both have to the same), then we
> >>>>
> >>>> both have to 'be' the same?
> >>>>
> >>>>> +      * can only return out the top buffer in the queue, and assume they have
> >>>>> +      * been synced by queuing at the same time. We cannot drop these frames,
> >>>>> +      * as they may have been provided externally.
> >>>>> +      */
> >>>>>       while (!q.empty()) {
> >>>>>               FrameBuffer *b = q.front();
> >>>>> -             if (b->metadata().timestamp < timestamp) {
> >>>>> +             if (!stream->isExternal() && b->metadata().timestamp < timestamp) {
> >>>>>                       q.pop();
> >>>>> -                     dev->queueBuffer(b);
> >>>>> -                     LOG(RPI, Warning) << "Dropping input frame!";
> >>>>> -             } else if (b->metadata().timestamp == timestamp) {
> >>>>> +                     stream->queueBuffer(b);
> >>>>> +                     LOG(RPI, Warning) << "Dropping unmatched input frame in stream "
> >>>>> +                                       << stream->name();
> >>>>> +             } else if (stream->isExternal() || b->metadata().timestamp == timestamp) {
> >>>>>                       /* The calling function will pop the item from the queue. */
> >>>>>                       return b;
> >>>>>               } else {
> >>>>> diff --git a/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp b/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
> >>>>> index 2edb8b59..02f8d3e0 100644
> >>>>> --- a/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
> >>>>> +++ b/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
> >>>>> @@ -21,30 +21,20 @@ V4L2VideoDevice *RPiStream::dev() const
> >>>>>
> >>>>>  void RPiStream::setExternal(bool external)
> >>>>>  {
> >>>>> +     /* Import streams cannot be external. */
> >>>>> +     assert(!external || !importOnly_);
> >>>>>       external_ = external;
> >>>>>  }
> >>>>>
> >>>>>  bool RPiStream::isExternal() const
> >>>>>  {
> >>>>> -     /*
> >>>>> -      * Import streams cannot be external.
> >>>>> -      *
> >>>>> -      * RAW capture is a special case where we simply copy the RAW
> >>>>> -      * buffer out of the request. All other buffer handling happens
> >>>>> -      * as if the stream is internal.
> >>>>> -      */
> >>>>> -     return external_ && !importOnly_;
> >>>>> -}
> >>>>> -
> >>>>> -bool RPiStream::isImporter() const
> >>>>> -{
> >>>>> -     return importOnly_;
> >>>>> +     return external_;
> >>>>>  }
> >>>>>
> >>>>>  void RPiStream::reset()
> >>>>>  {
> >>>>>       external_ = false;
> >>>>> -     internalBuffers_.clear();
> >>>>> +     clearBuffers();
> >>>>>  }
> >>>>>
> >>>>>  std::string RPiStream::name() const
> >>>>> @@ -52,65 +42,123 @@ std::string RPiStream::name() const
> >>>>>       return name_;
> >>>>>  }
> >>>>>
> >>>>> -void RPiStream::setExternalBuffers(std::vector<std::unique_ptr<FrameBuffer>> *buffers)
> >>>>> +void RPiStream::setExportedBuffers(std::vector<std::unique_ptr<FrameBuffer>> *buffers)
> >>>>>  {
> >>>>> -     externalBuffers_ = buffers;
> >>>>> +     std::transform(buffers->begin(), buffers->end(), std::back_inserter(bufferList_),
> >>>>> +                    [](std::unique_ptr<FrameBuffer> &b) { return b.get(); });
> >>>>>  }
> >>>>>
> >>>>> -const std::vector<std::unique_ptr<FrameBuffer>> *RPiStream::getBuffers() const
> >>>>> +const std::vector<FrameBuffer *> &RPiStream::getBuffers() const
> >>>>>  {
> >>>>> -     return external_ ? externalBuffers_ : &internalBuffers_;
> >>>>> +     return bufferList_;
> >>>>>  }
> >>>>>
> >>>>>  void RPiStream::releaseBuffers()
> >>>>>  {
> >>>>>       dev_->releaseBuffers();
> >>>>> -     if (!external_ && !importOnly_)
> >>>>> -             internalBuffers_.clear();
> >>>>> +     clearBuffers();
> >>>>>  }
> >>>>>
> >>>>> -int RPiStream::importBuffers(unsigned int count)
> >>>>> +int RPiStream::prepareBuffers(unsigned int count)
> >>>>>  {
> >>>>> +     int ret;
> >>>>> +
> >>>>> +     if (!importOnly_) {
> >>>>> +             if (count) {
> >>>>> +                     /* Export some frame buffers for internal use. */
> >>>>> +                     ret = dev_->exportBuffers(count, &internalBuffers_);
> >>>>> +                     if (ret < 0)
> >>>>> +                             return ret;
> >>>>> +
> >>>>> +                     /* Add these exported buffers to the internal/external buffer list. */
> >>>>> +                     setExportedBuffers(&internalBuffers_);
> >>>>> +
> >>>>> +                     /* Add these buffers to the queue of internal usable buffers. */
> >>>>> +                     for (auto const &buffer : internalBuffers_)
> >>>>> +                             availableBuffers_.push(buffer.get());
> >>>>> +             }
> >>>>> +
> >>>>> +             /* We must import all internal/external exported buffers. */
> >>>>> +             count = bufferList_.size();
> >>>>> +     }
> >>>>> +
> >>>>>       return dev_->importBuffers(count);
> >>>>>  }
> >>>>>
> >>>>> -int RPiStream::allocateBuffers(unsigned int count)
> >>>>> +int RPiStream::queueAllBuffers()
> >>>>>  {
> >>>>> -     return dev_->allocateBuffers(count, &internalBuffers_);
> >>>>> -}
> >>>>> +     int ret;
> >>>>>
> >>>>> -int RPiStream::queueBuffers()
> >>>>> -{
> >>>>>       if (external_)
> >>>>>               return 0;
> >>>>>
> >>>>> -     for (auto &b : internalBuffers_) {
> >>>>> -             int ret = dev_->queueBuffer(b.get());
> >>>>> -             if (ret) {
> >>>>> -                     LOG(RPISTREAM, Error) << "Failed to queue buffers for "
> >>>>> -                                           << name_;
> >>>>> +     while (!availableBuffers_.empty()) {
> >>>>> +             ret = queueBuffer(availableBuffers_.front());
> >>>>> +             if (ret < 0)
> >>>>>                       return ret;
> >>>>> -             }
> >>>>> +
> >>>>> +             availableBuffers_.pop();
> >>>>>       }
> >>>>>
> >>>>>       return 0;
> >>>>>  }
> >>>>>
> >>>>> -bool RPiStream::findFrameBuffer(FrameBuffer *buffer) const
> >>>>> +int RPiStream::queueBuffer(FrameBuffer *buffer)
> >>>>> +{
> >>>>> +     /*
> >>>>> +      * A nullptr buffer implies an external stream, but no external
> >>>>> +      * buffer has been supplied. So, pick one from the availableBuffers_
> >>>>> +      * queue.
> >>
> >> Aha, now I see this here, maybe the comment addition I suggested above
> >> is possibly redundant, as it's explained here ...
> >>
> >>>>> +      */
> >>>>> +     if (!buffer) {
> >>>>> +             if (availableBuffers_.empty()) {
> >>>>> +                     LOG(RPISTREAM, Warning) << "No buffers available for "
> >>>>> +                                             << name_;
> >>>>> +                     return -EINVAL;
> >>>>> +             }
> >>>>> +
> >>>>> +             buffer = availableBuffers_.front();
> >>>>> +             availableBuffers_.pop();
> >>>>> +     }
> >>>>> +
> >>>>> +     LOG(RPISTREAM, Debug) << "Queuing buffer " << buffer->cookie()
> >>>>> +                           << " for " << name_;
> >>>>> +
> >>>>> +     int ret = dev_->queueBuffer(buffer);
> >>>>> +     if (ret) {
> >>>>> +             LOG(RPISTREAM, Error) << "Failed to queue buffer for "
> >>>>> +                                   << name_;
> >>>>> +     }
> >>>>> +
> >>>>> +     return ret;
> >>>>> +}
> >>>>> +
> >>>>> +void RPiStream::returnBuffer(FrameBuffer *buffer)
> >>>>>  {
> >>>>> -     auto start = external_ ? externalBuffers_->begin() : internalBuffers_.begin();
> >>>>> -     auto end = external_ ? externalBuffers_->end() : internalBuffers_.end();
> >>>>> +     /* This can only be called for external streams. */
> >>>>> +     assert(external_);
> >>
> >> Could this use ASSERT() from libcamera/internal/log.h ?
> >>
> >>>>> +
> >>>>> +     availableBuffers_.push(buffer);
> >>>>> +}
> >>>>>
> >>>>> +bool RPiStream::findFrameBuffer(FrameBuffer *buffer) const
> >>>>> +{
> >>>>>       if (importOnly_)
> >>>>>               return false;
> >>>>>
> >>>>> -     if (std::find_if(start, end,
> >>>>> -                      [buffer](std::unique_ptr<FrameBuffer> const &ref) { return ref.get() == buffer; }) != end)
> >>>>> +     if (std::find(bufferList_.begin(), bufferList_.end(), buffer) != bufferList_.end())
> >>>>>               return true;
> >>>>>
> >>>>>       return false;
> >>>>>  }
> >>>>>
> >>>>> +void RPiStream::clearBuffers()
> >>>>> +{
> >>>>> +     availableBuffers_ = std::queue<FrameBuffer *>{};
> >>>>> +     internalBuffers_.clear();
> >>>>> +     bufferList_.clear();
> >>>>> +}
> >>>>> +
> >>>>>  } /* namespace RPi */
> >>>>>
> >>>>>  } /* namespace libcamera */
> >>>>> diff --git a/src/libcamera/pipeline/raspberrypi/rpi_stream.h b/src/libcamera/pipeline/raspberrypi/rpi_stream.h
> >>>>> index 3957e342..af9c2ad2 100644
> >>>>> --- a/src/libcamera/pipeline/raspberrypi/rpi_stream.h
> >>>>> +++ b/src/libcamera/pipeline/raspberrypi/rpi_stream.h
> >>>>> @@ -39,21 +39,22 @@ public:
> >>>>>       V4L2VideoDevice *dev() const;
> >>>>>       void setExternal(bool external);
> >>>>>       bool isExternal() const;
> >>>>> -     bool isImporter() const;
> >>>>>       void reset();
> >>>>>       std::string name() const;
> >>>>> -     void setExternalBuffers(std::vector<std::unique_ptr<FrameBuffer>> *buffers);
> >>>>> -     const std::vector<std::unique_ptr<FrameBuffer>> *getBuffers() const;
> >>>>> +     void setExportedBuffers(std::vector<std::unique_ptr<FrameBuffer>> *buffers);
> >>>>> +     const std::vector<FrameBuffer *> &getBuffers() const;
> >>>>>       void releaseBuffers();
> >>>>> -     int importBuffers(unsigned int count);
> >>>>> -     int allocateBuffers(unsigned int count);
> >>>>> -     int queueBuffers();
> >>>>> +     int prepareBuffers(unsigned int count);
> >>>>> +     int queueAllBuffers();
> >>>>> +     int queueBuffer(FrameBuffer *buffer);
> >>>>> +     void returnBuffer(FrameBuffer *buffer);
> >>>>>       bool findFrameBuffer(FrameBuffer *buffer) const;
> >>>>
> >>>> Perhaps we should break those up into sections in patch 1/9. It's hard
> >>>> to see the wood-for-the-trees in the wall of function declarations.
> >>>
> >>> Not sure I follow what you mean?
> >>
> >> There is a lot of text all bunched up together, so it's hard to get my
> >> eyes around the class members.
> >>
> >> It would be nice to group functions with some line breaks to make it
> >> easier on the eye.
> >>
> >> But that should happen in patch 1/9, so I'll go comment on it there. I
> >> skipped it before because that patch just moves code around, but I thnik
> >> it can also improve formatting for readability.
> >>
> >>>>>
> >>>>>  private:
> >>>>> +     void clearBuffers();
> >>>>>       /*
> >>>>>        * Indicates that this stream is active externally, i.e. the buffers
> >>>>> -      * are provided by the application.
> >>>>> +      * might be provided by (and returned to) the application.
> >>>>>        */
> >>>>>       bool external_;
> >>>>>       /* Indicates that this stream only imports buffers, e.g. ISP input. */
> >>>>> @@ -62,10 +63,19 @@ private:
> >>>>>       std::string name_;
> >>>>>       /* The actual device stream. */
> >>>>>       std::unique_ptr<V4L2VideoDevice> dev_;
> >>>>> -     /* Internally allocated framebuffers associated with this device stream. */
> >>>>> +     /* All framebuffers associated with this device stream. */
> >>>>> +     std::vector<FrameBuffer *> bufferList_;
> >>>>> +     /*
> >>>>> +      * List of frame buffer that we can use if none have been provided by
> >>>>> +      * the application for external streams. This is populated by the
> >>>>> +      * buffers exported internally.
> >>>>> +      */
> >>>>> +     std::queue<FrameBuffer *> availableBuffers_;
> >>>>> +     /*
> >>>>> +      * This is a list of buffers exported internally. Need to keep this around
> >>>>> +      * as the stream needs to maintain ownership of these buffers.
> >>>>> +      */
> >>>>>       std::vector<std::unique_ptr<FrameBuffer>> internalBuffers_;
> >>>>> -     /* Externally allocated framebuffers associated with this device stream. */
> >>>>> -     std::vector<std::unique_ptr<FrameBuffer>> *externalBuffers_;
> >>>>
> >>>> Likewise here, some whitespace to break up these members would really
> >>>> help, as by the time I've got here I've got definite review fatigue and
> >>>> lots of lines close together just become a blur ... :S
> >>>
> >>> That's not a problem.
> >>
> >> But for this patch, I can't see anything wrong ... and I can see how
> >> it's helping manage buffers to allow optional buffers on a stream for
> >> RAW zero copy support.
> >>
> >> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> >>
> >>>>>  };
> >>>>>
> >>>>>  /*

-- 
Regards,

Laurent Pinchart


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