[Mesa-dev] What is DRI_IMAGE and do I want it?

[Ilia Mirkin]

On Thu, Feb 13, 2014 at 12:33 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> Hello list,
>
> A number of piglit tests fail with the nouveau dri driver (for
> pre-nv30 cards), e.g.
>
> http://people.freedesktop.org/~imirkin/nv10-comparison/nv18-imirkin/spec/EGL_EXT_client_extensions/conformance%20test%203.html
>
> libEGL fatal: DRI2: did not find extension DRI_IMAGE version 1
>
> I noticed that the nouveau driver extensions are specified as
>
> static const __DRIextension *nouveau_driver_extensions[] = {
> &driCoreExtension.base,
> &driDRI2Extension.base,
> &nouveau_vtable.base,
> NULL
> };
>
> without &driImageDriverExtension.base in there (which is only used by
> i915/i965, although I assume st/dri implements it in its own way),
> which is most likely the cause of that failure. I looked at the
> functions pointed at by the structure, and they all seem to be
> available with the nouveau driver (but there could be something subtle
> I'm missing). So... should I just drop in
> &driImageDriverExtension.base into the list? What is it for? Is there
> a downside to including it?

In the meanwhile I also noticed that there are screen extensions that
would also need to be added, making this a less trivial change.
However I'm still curious as to what this is used for, and whether it
should be added, or whether I should just do "-x egl" in piglit and
move on.

>
> As a side-note, what _does_ appear to be missing is
> Allocate/ReleaseBuffer, seemingly needed by the DRI2 stuff. Perhaps
> some of the failures are due to that :)
>
> Thanks,
>
>   -ilia