From 566ccd75cafd0bd9d60d350405ca7d337786ae39 Mon Sep 17 00:00:00 2001 From: Paul Elder Date: Tue, 16 Jun 2020 16:40:34 +0900 Subject: v4l2: v4l2_camera: Don't use libcamera::Semaphore for available buffers In V4L2, a blocked dqbuf should not not also block a streamoff. This means that on streamoff, the blocked dqbuf must return (with error). We cannot do this with the libcamera semaphore, so pull out the necessary components of a semaphore, and put them into V4L2Camera, so that dqbuf from V4L2CameraProxy can wait on a disjunct condition of the availability of the semaphore or the stopping of the stream. Signed-off-by: Paul Elder Reviewed-by: Laurent Pinchart --- src/v4l2/v4l2_camera.cpp | 34 +++++++++++++++++++++++++++++++--- 1 file changed, 31 insertions(+), 3 deletions(-) (limited to 'src/v4l2/v4l2_camera.cpp') diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp index 177b1ea5..f7df9b85 100644 --- a/src/v4l2/v4l2_camera.cpp +++ b/src/v4l2/v4l2_camera.cpp @@ -18,7 +18,7 @@ LOG_DECLARE_CATEGORY(V4L2Compat); V4L2Camera::V4L2Camera(std::shared_ptr camera) : camera_(camera), isRunning_(false), bufferAllocator_(nullptr), - efd_(-1) + efd_(-1), bufferAvailableCount_(0) { camera_->requestCompleted.connect(this, &V4L2Camera::requestComplete); } @@ -100,7 +100,11 @@ void V4L2Camera::requestComplete(Request *request) if (ret != sizeof(data)) LOG(V4L2Compat, Error) << "Failed to signal eventfd POLLIN"; - bufferSema_.release(); + { + MutexLocker locker(bufferMutex_); + bufferAvailableCount_++; + } + bufferCV_.notify_all(); } int V4L2Camera::configure(StreamConfiguration *streamConfigOut, @@ -192,7 +196,11 @@ int V4L2Camera::streamOff() if (ret < 0) return ret == -EACCES ? -EBUSY : ret; - isRunning_ = false; + { + MutexLocker locker(bufferMutex_); + isRunning_ = false; + } + bufferCV_.notify_all(); return 0; } @@ -228,6 +236,26 @@ int V4L2Camera::qbuf(unsigned int index) return 0; } +void V4L2Camera::waitForBufferAvailable() +{ + MutexLocker locker(bufferMutex_); + bufferCV_.wait(locker, [&] { + return bufferAvailableCount_ >= 1 || !isRunning_; + }); + if (isRunning_) + bufferAvailableCount_--; +} + +bool V4L2Camera::isBufferAvailable() +{ + MutexLocker locker(bufferMutex_); + if (bufferAvailableCount_ < 1) + return false; + + bufferAvailableCount_--; + return true; +} + bool V4L2Camera::isRunning() { return isRunning_; -- cgit v1.2.1