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_proxy.cpp | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'src/v4l2/v4l2_camera_proxy.cpp') diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp index 7bf9e7f8..a222795d 100644 --- a/src/v4l2/v4l2_camera_proxy.cpp +++ b/src/v4l2/v4l2_camera_proxy.cpp @@ -588,10 +588,17 @@ int V4L2CameraProxy::vidioc_dqbuf(V4L2CameraFile *file, struct v4l2_buffer *arg) return -EINVAL; if (!file->nonBlocking()) - vcam_->bufferSema_.acquire(); - else if (!vcam_->bufferSema_.tryAcquire()) + vcam_->waitForBufferAvailable(); + else if (!vcam_->isBufferAvailable()) return -EAGAIN; + /* + * We need to check here again in case stream was turned off while we + * were blocked on waitForBufferAvailable(). + */ + if (!vcam_->isRunning()) + return -EINVAL; + updateBuffers(); struct v4l2_buffer &buf = buffers_[currentBuf_]; -- cgit v1.2.1