On Wed, Nov 23, 2022 at 08:24:37PM +0100, Daniel Vetter wrote:
> It's a bit a FAQ, and we really can't claim to be the authoritative
> source for allocating these numbers used in many standard extensions
> if we tell closed source or vendor stacks in general to go away.
>
> Iirc this was already clarified in some vulkan discussions, but I
> can't find that anywhere anymore. At least not in a public link.
>
> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Cc: Maxime Ripard <mripard@xxxxxxxxxx>
> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Cc: Alex Deucher <alexdeucher@xxxxxxxxx>
> Cc: Daniel Stone <daniel@xxxxxxxxxxxxx>
> Cc: Bas Nieuwenhuizen <bas@xxxxxxxxxxxxxxxxxxx>
> Cc: Jason Ekstrand <jason@xxxxxxxxxxxxxx>
> Cc: Neil Trevett <ntrevett@xxxxxxxxxx>
> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
>From irc:
<airlied> danvet: ack from me
> ---
> include/uapi/drm/drm_fourcc.h | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index bc056f2d537d..de703c6be969 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -88,6 +88,18 @@ extern "C" {
> *
> * The authoritative list of format modifier codes is found in
> * `include/uapi/drm/drm_fourcc.h`
> + *
> + * Open Source User Waiver
> + * -----------------------
> + *
> + * Because this is the authoritative source for pixel formats and modifiers
> + * referenced by GL, Vulkan extensions and other standards and hence used both
> + * by open source and closed source driver stacks, the usual requirement for an
> + * upstream in-kernel or open source userspace user does not apply.
> + *
> + * To ensure, as much as feasible, compatibility across stacks and avoid
> + * confusion with incompatible enumerations stakeholders for all relevant driver
> + * stacks should approve additions.
> */
>
> #define fourcc_code(a, b, c, d) ((__u32)(a) | ((__u32)(b) << 8) | \
> --
> 2.37.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
