[PATCH] media: hantro: Empty encoder capture buffers by default

[Chen-Yu Tsai]

The payload size for encoder capture buffers is set by the driver upon
finishing encoding each frame, based on the encoded length returned from
hardware, and whatever header and padding length used. Setting a
non-zero default serves no real purpose, and also causes issues if the
capture buffer is returned to userspace unused, confusing the
application.

Instead, always set the payload size to 0 for encoder capture buffers
when preparing them.

Fixes: 775fec69008d ("media: add Rockchip VPU JPEG encoder driver")
Fixes: 082aaecff35f ("media: hantro: Fix .buf_prepare")
Signed-off-by: Chen-Yu Tsai <wenst at chromium.org>
---

This was previously incorrectly squashed into my Hantro encoder cmd
patch [1].

[1] https://lore.kernel.org/linux-media/20220301042225.1540019-1-wenst@chromium.org/

 drivers/staging/media/hantro/hantro_v4l2.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/hantro/hantro_v4l2.c b/drivers/staging/media/hantro/hantro_v4l2.c
index 67148ba346f5..261beb0c40f6 100644
--- a/drivers/staging/media/hantro/hantro_v4l2.c
+++ b/drivers/staging/media/hantro/hantro_v4l2.c
@@ -733,8 +733,12 @@ static int hantro_buf_prepare(struct vb2_buffer *vb)
 	 * (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);
+	if (V4L2_TYPE_IS_CAPTURE(vq->type)) {
+		if (ctx->is_encoder)
+			vb2_set_plane_payload(vb, 0, 0);
+		else
+			vb2_set_plane_payload(vb, 0, pix_fmt->plane_fmt[0].sizeimage);
+	}
 
 	return 0;
 }
-- 
2.35.1.1021.g381101b075-goog