[Mesa-dev] [PATCH] i965: Fix bugs in intel_from_planar

[Jason Ekstrand]

On Mon, Feb 12, 2018 at 6:36 AM, Daniel Stone <daniel at fooishbar.org> wrote:

> Hi,
>
> On 10 February 2018 at 06:50, Jason Ekstrand <jason at jlekstrand.net> wrote:
> > -    } else if (parent->planar_format == NULL) {
> > +
> > +    const struct intel_image_format *f = parent->planar_format;
> > +    const int nplanes = f ? f->nplanes : 1;
> > +
> > +    if (plane > nplanes) {
> > +       if (parent->modifier == DRM_FORMAT_MOD_INVALID)
> > +          return NULL;
> > +
> >         const bool is_aux =
> >            isl_drm_modifier_has_aux(parent->modifier) && plane == 1;
> >         if (!is_aux)
> > @@ -1332,10 +1338,6 @@ intel_from_planar(__DRIimage *parent, int plane,
> void *loaderPrivate)
> >      } else {
> >         /* Planar formats don't support aux buffers/images */
> >         assert(!isl_drm_modifier_has_aux(parent->modifier));
> > -       f = parent->planar_format;
> > -
> > -       if (plane >= f->nplanes)
> > -          return NULL;
>
> On further thought, I don't see how this could work at all. If we call
> fromPlanar on plane 0 of a non-planar image with an aux plane, we need
> to land in the first branch (due to the assert). But since plane 0 is
> strictly less than the number of planes 1, we don't.
>
> I think something like this: https://hastebin.com/axuqorenax
>

I like that.  Mind making a proper patch out of it (not based on this one)
and sending to the list?  Between the four of us, maybe we can write this
correctly. :-)

--Jason
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