Hello Gustavo, On 03/13/2017 04:20 PM, Gustavo Padovan wrote: [snip] > > int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) > { > + struct dma_fence *fence = NULL; > int ret; > > if (vb2_fileio_is_active(q)) { > @@ -565,7 +567,17 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b) > } > > ret = vb2_queue_or_prepare_buf(q, b, "qbuf"); > - return ret ? ret : vb2_core_qbuf(q, b->index, b); > + > + if (b->flags & V4L2_BUF_FLAG_IN_FENCE) { > + if (b->memory != VB2_MEMORY_DMABUF) > + return -EINVAL; > + I wonder if is correct to check this. Only one side of the pipeline uses V4L2_MEMORY_DMABUF while the other uses V4L2_MEMORY_MMAP + VIDIOC_EXPBUF. So that means that fences can only be used in one direction? Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America