@@ -116,28 +116,64 @@ int RPiStream::queueBuffer(FrameBuffer *buffer)
if (availableBuffers_.empty()) {
LOG(RPISTREAM, Warning) << "No buffers available for "
<< name_;
- return -EINVAL;
+ /*
+ * Note that we need to requeue an internal buffer as soon
+ * as one becomes available.
+ */
+ requeueBuffers_.push(nullptr);
+ return -ENOMEM;
}
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_;
+ if (requeueBuffers_.empty()) {
+ /*
+ * No earlier requests are pending to be queued, so we can
+ * go ahead and queue the buffer into the device.
+ */
+ return queueToDevice(buffer);
+ } else {
+ /*
+ * There are earlier buffers to be queued, so this buffer
+ * must go on the waiting list.
+ */
+ requeueBuffers_.push(buffer);
+ return 0;
}
-
- return ret;
}
void RPiStream::returnBuffer(FrameBuffer *buffer)
{
+ /* Push this buffer back into the queue to be used again. */
availableBuffers_.push(buffer);
+
+ /*
+ * Do we have any buffers that are waiting to be queued?
+ * If so, do it now as availableBuffers_ will not be empty.
+ */
+ while (!requeueBuffers_.empty()) {
+ FrameBuffer *buffer = requeueBuffers_.front();
+ requeueBuffers_.pop();
+
+ if (!buffer && !availableBuffers_.empty()) {
+ /*
+ * We want to queue an internal buffer, and at
+ * least one is available.
+ */
+ buffer = availableBuffers_.front();
+ availableBuffers_.pop();
+ } else if (!buffer && availableBuffers_.empty()) {
+ /*
+ * We want to queue an internal buffer, but none
+ * are available. Can't do anything, quit the loop.
+ */
+ break;
+ }
+
+ queueToDevice(buffer);
+ }
}
bool RPiStream::findFrameBuffer(FrameBuffer *buffer) const
@@ -154,10 +190,23 @@ bool RPiStream::findFrameBuffer(FrameBuffer *buffer) const
void RPiStream::clearBuffers()
{
availableBuffers_ = std::queue<FrameBuffer *>{};
+ requeueBuffers_ = std::queue<FrameBuffer *>{};
internalBuffers_.clear();
bufferList_.clear();
}
+int RPiStream::queueToDevice(FrameBuffer *buffer)
+{
+ 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;
+}
+
} /* namespace RPi */
} /* namespace libcamera */
@@ -51,6 +51,7 @@ public:
private:
void clearBuffers();
+ int queueToDevice(FrameBuffer *buffer);
/*
* Indicates that this stream is active externally, i.e. the buffers
* might be provided by (and returned to) the application.
@@ -62,7 +63,7 @@ private:
std::string name_;
/* The actual device stream. */
std::unique_ptr<V4L2VideoDevice> dev_;
- /* All framebuffers associated with this device stream. */
+ /* All frame buffers associated with this device stream. */
std::vector<FrameBuffer *> bufferList_;
/*
* List of frame buffer that we can use if none have been provided by
@@ -70,6 +71,15 @@ private:
* buffers exported internally.
*/
std::queue<FrameBuffer *> availableBuffers_;
+ /*
+ * List of frame buffer that are to be re-queued into the device.
+ * A nullptr indicates any internal buffer can be used (from availableBuffers_),
+ * whereas a valid pointer indicates an external buffer to be queued.
+ *
+ * Ordering buffers to be queued is important here as it must match the
+ * requests coming from the application.
+ */
+ std::queue<FrameBuffer *> requeueBuffers_;
/*
* This is a list of buffers exported internally. Need to keep this around
* as the stream needs to maintain ownership of these buffers.
Add further queueing into the RPiStream object to ensure that we always follow the buffer ordering (be it internal or external) given by incoming Requests. This is essential, otherwise we risk dropping frames that are meant to be part of a Request, and can cause the pipeline to stall indefinitely. This also prevents any possibility of mismatched frame buffers going through the pipeline and out to the application. Signed-off-by: Naushir Patuck <naush@raspberrypi.com> --- .../pipeline/raspberrypi/rpi_stream.cpp | 69 ++++++++++++++++--- .../pipeline/raspberrypi/rpi_stream.h | 12 +++- 2 files changed, 70 insertions(+), 11 deletions(-)