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

[Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>]

On Thu, Mar 31, 2022 at 04:49:06PM +0800, Chen-Yu Tsai wrote:
> 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@chromium.org>

Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

> ---
> 
> 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
>