[PATCH] drm/fourcc: Document open source user waiver

[Daniel Vetter]

On Thu, 1 Dec 2022 at 11:07, Daniel Vetter <daniel at ffwll.ch> wrote:
>
> 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 at linux.intel.com>
> > Cc: Maxime Ripard <mripard at kernel.org>
> > Cc: Thomas Zimmermann <tzimmermann at suse.de>
> > Cc: David Airlie <airlied at gmail.com>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Cc: Alex Deucher <alexdeucher at gmail.com>
> > Cc: Daniel Stone <daniel at fooishbar.org>
> > Cc: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> > Cc: Jason Ekstrand <jason at jlekstrand.net>
> > Cc: Neil Trevett <ntrevett at nvidia.com>
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
>
> From irc:
>
> <airlied> danvet: ack from me

Also from irc:

<mareko> danvet: Acked

-Daniel

> > ---
> >  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



-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch