The driver should only set the payload on .buf_prepare if the buffer is CAPTURE type. If an OUTPUT buffer has a zero bytesused set by userspace then v4l2-core will set it to buffer length. If we overwrite bytesused for OUTPUT buffers, too, then vb2_get_plane_payload() will return incorrect value which might be then written to hw registers by the driver in hantro_g1_h264_dec.c. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx> --- drivers/staging/media/hantro/hantro_v4l2.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/staging/media/hantro/hantro_v4l2.c b/drivers/staging/media/hantro/hantro_v4l2.c index 1bc118e375a1..7ccc6405036a 100644 --- a/drivers/staging/media/hantro/hantro_v4l2.c +++ b/drivers/staging/media/hantro/hantro_v4l2.c @@ -639,7 +639,14 @@ static int hantro_buf_prepare(struct vb2_buffer *vb) ret = hantro_buf_plane_check(vb, pix_fmt); if (ret) return ret; - vb2_set_plane_payload(vb, 0, pix_fmt->plane_fmt[0].sizeimage); + /* + * Buffer's bytesused must be written by driver for CAPTURE buffers. + * (for OUTPUT buffers, if userspace passes 0 bytesused, v4l2-core sets + * it to buffer length). + */ + if (V4L2_TYPE_IS_CAPTURE(vq->type)) + vb2_set_plane_payload(vb, 0, pix_fmt->plane_fmt[0].sizeimage); + return 0; } -- 2.17.1
