2 files changed, 18 insertions, 3 deletions

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index c2126d874549..25d3ae2188cb 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -971,6 +971,7 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
          * to the userspace.
          */
         req->count = allocated_buffers;
+        q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
 
         return 0;
 }
@@ -1018,6 +1019,7 @@ static int __create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create
                 memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
                 memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
                 q->memory = create->memory;
+                q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
         }
 
         num_buffers = min(create->count, VIDEO_MAX_FRAME - q->num_buffers);
@@ -1821,6 +1823,7 @@ static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
          */
         list_add_tail(&vb->queued_entry, &q->queued_list);
         q->queued_count++;
+        q->waiting_for_buffers = false;
         vb->state = VB2_BUF_STATE_QUEUED;
         if (V4L2_TYPE_IS_OUTPUT(q->type)) {
                 /*
@@ -2287,6 +2290,7 @@ static int vb2_internal_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
          * their normal dequeued state.
          */
         __vb2_queue_cancel(q);
+        q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
 
         dprintk(3, "successful\n");
         return 0;
@@ -2605,10 +2609,17 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
         }
 
         /*
-         * There is nothing to wait for if no buffer has been queued and the
-         * queue isn't streaming, or if the error flag is set.
+         * There is nothing to wait for if the queue isn't streaming, or if the
+         * error flag is set.
          */
-        if ((list_empty(&q->queued_list) && !vb2_is_streaming(q)) || q->error)
+        if (!vb2_is_streaming(q) || q->error)
+                return res | POLLERR;
+        /*
+         * For compatibility with vb1: if QBUF hasn't been called yet, then
+         * return POLLERR as well. This only affects capture queues, output
+         * queues will always initialize waiting_for_buffers to false.
+         */
+        if (q->waiting_for_buffers)
                 return res | POLLERR;
 
         /*
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 80fa7253e483..2fefcf491aa8 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -380,6 +380,9 @@ struct v4l2_fh;
  * @start_streaming_called: start_streaming() was called successfully and we
  *              started streaming.
  * @error:      a fatal error occurred on the queue
+ * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for
+ *              buffers. Only set for capture queues if qbuf has not yet been
+ *              called since poll() needs to return POLLERR in that situation.
  * @fileio:     file io emulator internal data, used only if emulator is active
  * @threadio:   thread io internal data, used only if thread is active
  */
@@ -417,6 +420,7 @@ struct vb2_queue {
         unsigned int                    streaming:1;
         unsigned int                    start_streaming_called:1;
         unsigned int                    error:1;
+        unsigned int                    waiting_for_buffers:1;
 
         struct vb2_fileio_data          *fileio;
         struct vb2_threadio_data        *threadio;