media: hantro: Fix .buf_prepare

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@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/staging/media/hantro/hantro_v4l2.c b/drivers/staging/media/hantro/hantro_v4l2.c
index 1bc118e375a12c5f2b126cf02c4495bff60fd130..7ccc6405036ae19976da9cd3bd891f0351d0b632 100644 (file)
--- 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;
 }