[PATCH v4 1/3] media: rkvdec: Fix .buf_prepare

[Ezequiel Garcia <ezequiel@collabora.com>]

The driver should only set the payload on .buf_prepare
if the buffer is CAPTURE type, or if an OUTPUT buffer
has a zeroed payload.

Fix it.

Fixes: cd33c830448ba ("media: rkvdec: Add the rkvdec driver")
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
---
 drivers/staging/media/rkvdec/rkvdec.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/media/rkvdec/rkvdec.c b/drivers/staging/media/rkvdec/rkvdec.c
index 225eeca73356..4df2a248ab96 100644
--- a/drivers/staging/media/rkvdec/rkvdec.c
+++ b/drivers/staging/media/rkvdec/rkvdec.c
@@ -456,7 +456,15 @@ static int rkvdec_buf_prepare(struct vb2_buffer *vb)
 		if (vb2_plane_size(vb, i) < sizeimage)
 			return -EINVAL;
 	}
-	vb2_set_plane_payload(vb, 0, f->fmt.pix_mp.plane_fmt[0].sizeimage);
+
+	/*
+	 * Buffer's bytesused is written by the driver for CAPTURE buffers,
+	 * or if the application passed zero bytesused on an OUTPUT buffer.
+	 */
+	if (!V4L2_TYPE_IS_OUTPUT(vq->type) ||
+	    (V4L2_TYPE_IS_OUTPUT(vq->type) && !vb2_get_plane_payload(vb, 0)))
+		vb2_set_plane_payload(vb, 0,
+				      f->fmt.pix_mp.plane_fmt[0].sizeimage);
 	return 0;
 }
 
-- 
2.26.0.rc2