On 06/16/17 09:39, Gustavo Padovan wrote:
> From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
>
> If V4L2_BUF_FLAG_OUT_FENCE flag is present on the QBUF call we create
> an out_fence for the buffer and return it to userspace on the fence_fd
> field. It only works with ordered queues.
>
> The fence is signaled on buffer_done(), when the job on the buffer is
> finished.
>
> v2: check if the queue is ordered.
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
> ---
> drivers/media/v4l2-core/videobuf2-core.c | 6 ++++++
> drivers/media/v4l2-core/videobuf2-v4l2.c | 22 +++++++++++++++++++++-
> 2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
> index 21cc4ed..a57902ee 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -356,6 +356,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
> vb->planes[plane].length = plane_sizes[plane];
> vb->planes[plane].min_length = plane_sizes[plane];
> }
> + vb->out_fence_fd = -1;
> q->bufs[vb->index] = vb;
>
> /* Allocate video buffer memory for the MMAP type */
> @@ -940,6 +941,11 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> __enqueue_in_driver(vb);
> return;
> default:
> + dma_fence_signal(vb->out_fence);
> + dma_fence_put(vb->out_fence);
> + vb->out_fence = NULL;
> + vb->out_fence_fd = -1;
> +
> /* Inform any processes that may be waiting for buffers */
> wake_up(&q->done_wq);
> break;
case VB2_BUF_STATE_REQUEUEING: a driver that calls this would break the ordering
requirement. I would suggest a WARN_ON_ONCE(q->ordered) call there together with
a comment.
> diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c
> index e6ad77f..e2733dd 100644
> --- a/drivers/media/v4l2-core/videobuf2-v4l2.c
> +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
> @@ -204,9 +204,14 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb)
> b->timestamp = ns_to_timeval(vb->timestamp);
> b->timecode = vbuf->timecode;
> b->sequence = vbuf->sequence;
> - b->fence_fd = -1;
> + b->fence_fd = vb->out_fence_fd;
> b->reserved = 0;
>
> + if (vb->sync_file) {
> + fd_install(vb->out_fence_fd, vb->sync_file->file);
> + vb->sync_file = NULL;
I'm no fence expert, but this seems the wrong place for this.
> + }
> +
You need to set the OUT_FENCE flag if there is a fence pending.
> if (q->is_multiplanar) {
> /*
> * Fill in plane-related data if userspace provided an array
> @@ -581,6 +586,21 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
> }
> }
>
> + if (b->flags & V4L2_BUF_FLAG_OUT_FENCE) {
> + if (!q->ordered) {
> + dprintk(1, "can't use out-fences with unordered queues\n");
> + dma_fence_put(fence);
> + return -EINVAL;
> + }
> +
> + ret = vb2_setup_out_fence(q, b->index);
> + if (ret) {
> + dprintk(1, "failed to set up out-fence\n");
> + dma_fence_put(fence);
> + return ret;
> + }
> + }
> +
> return ret ? ret : vb2_core_qbuf(q, b->index, b, fence);
Wouldn't it make more sense to do the fd_install after this call?
Besides, if vb2_core_qbuf returns with an error, then I expect that
we need to clean up the fence?
> }
> EXPORT_SYMBOL_GPL(vb2_qbuf);
>
Regards,
Hans
