diff options
| -rw-r--r-- | src/gstreamer/gstlibcamerasrc.cpp | 71 |
1 files changed, 50 insertions, 21 deletions
diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp index 9ea59631..a7a0c440 100644 --- a/src/gstreamer/gstlibcamerasrc.cpp +++ b/src/gstreamer/gstlibcamerasrc.cpp @@ -259,6 +259,7 @@ GstLibcameraSrcState::requestCompleted(Request *request) int GstLibcameraSrcState::processRequest() { std::unique_ptr<RequestWrap> wrap; + int err = 0; { MutexLocker locker(lock_); @@ -267,10 +268,13 @@ int GstLibcameraSrcState::processRequest() wrap = std::move(completedRequests_.front()); completedRequests_.pop(); } + + if (completedRequests_.empty()) + err = -ENOBUFS; } if (!wrap) - return -ENODATA; + return -ENOBUFS; GstFlowReturn ret = GST_FLOW_OK; gst_flow_combiner_reset(src_->flow_combiner); @@ -310,7 +314,7 @@ int GstLibcameraSrcState::processRequest() return -EPIPE; } - return 0; + return err; } static bool @@ -381,46 +385,71 @@ gst_libcamera_src_task_run(gpointer user_data) GstLibcameraSrcState *state = self->state; /* + * Start by pausing the task. The task may also get resumed by the + * buffer-notify signal when new buffers are queued back to the pool, + * or by the request completion handler when a new request has + * completed. Both will resume the task after adding the buffers or + * request to their respective lists, which are checked below to decide + * if the task needs to be resumed for another iteration. This is thus + * guaranteed to be race-free, the lock taken by gst_task_pause() and + * gst_task_resume() serves as a memory barrier. + */ + gst_task_pause(self->task); + + bool doResume = false; + + /* * Create and queue one request. If no buffers are available the * function returns -ENOBUFS, which we ignore here as that's not a * fatal error. */ int ret = state->queueRequest(); - if (ret == -ENOMEM) { + switch (ret) { + case 0: + /* + * The request was successfully queued, there may be enough + * buffers to create a new one. Don't pause the task to give it + * another try. + */ + doResume = true; + break; + + case -ENOMEM: GST_ELEMENT_ERROR(self, RESOURCE, NO_SPACE_LEFT, ("Failed to allocate request for camera '%s'.", state->cam_->id().c_str()), ("libcamera::Camera::createRequest() failed")); gst_task_stop(self->task); return; + + case -ENOBUFS: + default: + break; } - /* Process one completed request, if available. */ + /* + * Process one completed request, if available, and record if further + * requests are ready for processing. + */ ret = state->processRequest(); switch (ret) { + case 0: + /* Another completed request is available, resume the task. */ + doResume = true; + break; + case -EPIPE: gst_task_stop(self->task); return; - case -ENODATA: - gst_task_pause(self->task); - return; - } - - /* - * Here we need to decide if we want to pause. This needs to - * happen in lock step with the callback thread which may want - * to resume the task and might push pending buffers. - */ - bool do_pause; - - { - MutexLocker locker(state->lock_); - do_pause = state->completedRequests_.empty(); + case -ENOBUFS: + default: + break; } - if (do_pause) - gst_task_pause(self->task); + /* Resume the task for another iteration if needed. */ + if (doResume) + gst_task_resume(self->task); } static void |