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 <andrze...@collabora.com>
---
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
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