[media] vb2: allow requeuing buffers while streaming

vb2_buffer_done() already allows STATE_QUEUED, but currently only when not
streaming. It is useful to allow it while streaming as well, as this makes
it possible for drivers to requeue buffers while waiting for a stable
video signal.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 552d7e127c39864dff59d7cda8e9d694413b08c9..1a096a62ef309d177112971f7e2cb7e62e1559d0 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -182,6 +182,7 @@ module_param(debug, int, 0644);
                                 V4L2_BUF_FLAG_KEYFRAME | V4L2_BUF_FLAG_TIMECODE)
 
 static void __vb2_queue_cancel(struct vb2_queue *q);
+static void __enqueue_in_driver(struct vb2_buffer *vb);
 
 /**
  * __vb2_buf_mem_alloc() - allocate video memory for the given buffer
@@ -1153,8 +1154,9 @@ EXPORT_SYMBOL_GPL(vb2_plane_cookie);
 /**
  * vb2_buffer_done() - inform videobuf that an operation on a buffer is finished
  * @vb:                vb2_buffer returned from the driver
- * @state:     either VB2_BUF_STATE_DONE if the operation finished successfully
- *             or VB2_BUF_STATE_ERROR if the operation finished with an error.
+ * @state:     either VB2_BUF_STATE_DONE if the operation finished successfully,
+ *             VB2_BUF_STATE_ERROR if the operation finished with an error or
+ *             VB2_BUF_STATE_QUEUED if the driver wants to requeue buffers.
  *             If start_streaming fails then it should return buffers with state
  *             VB2_BUF_STATE_QUEUED to put them back into the queue.
  *
@@ -1205,8 +1207,11 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
        atomic_dec(&q->owned_by_drv_count);
        spin_unlock_irqrestore(&q->done_lock, flags);
 
-       if (state == VB2_BUF_STATE_QUEUED)
+       if (state == VB2_BUF_STATE_QUEUED) {
+               if (q->start_streaming_called)
+                       __enqueue_in_driver(vb);
                return;
+       }
 
        /* Inform any processes that may be waiting for buffers */
        wake_up(&q->done_wq);