Re: [PATCH v3 1/2] media: uapi: Add H264 low-level decoder API compound controls.

[Ezequiel Garcia <ezequiel@collabora.com>]

On Mon, 2019-02-11 at 15:39 +0100, Maxime Ripard wrote:
> From: Pawel Osciak <posciak@chromium.org>
> 
> Stateless video codecs will require both the H264 metadata and slices in
> order to be able to decode frames.
> 
> This introduces the definitions for a new pixel format for H264 slices that
> have been parsed, as well as the structures used to pass the metadata from
> the userspace to the kernel.
> 
> Co-Developed-by: Maxime Ripard <maxime.ripard@bootlin.com>
> Signed-off-by: Pawel Osciak <posciak@chromium.org>
> Signed-off-by: Guenter Roeck <groeck@chromium.org>
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
[..]
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * These are the H.264 state controls for use with stateless H.264
> + * codec drivers.
> + *
> + * It turns out that these structs are not stable yet and will undergo
> + * more changes. So keep them private until they are stable and ready to
> + * become part of the official public API.
> + */
> +
> +#ifndef _H264_CTRLS_H_
> +#define _H264_CTRLS_H_
> +
> +#define V4L2_CID_MPEG_VIDEO_H264_SPS		(V4L2_CID_MPEG_BASE+383)
> +#define V4L2_CID_MPEG_VIDEO_H264_PPS		(V4L2_CID_MPEG_BASE+384)
> +#define V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX	(V4L2_CID_MPEG_BASE+385)
> +#define V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS	(V4L2_CID_MPEG_BASE+386)
> +#define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS	(V4L2_CID_MPEG_BASE+387)
> +

Note that these integers (+383, ..) are already in-use.

Since the controls are non-public, perhaps we could use upper integers,
say +1000 or something?