[Intel-gfx] [PATCH 17/37] drm/i915: Test partial mappings

[Chris Wilson]

On Tue, Jan 17, 2017 at 12:12:50PM +0000, Matthew Auld wrote:
> > +               for (pitch = 1; pitch <= max_pitch; pitch <<= 1) {
> > +                       tile.stride = tile.width * pitch;
> > +                       err = check_partial_mapping(obj, &tile);
> > +                       if (err)
> > +                               goto err_unlock;
> > +               }
> > +
> > +               if (INTEL_GEN(i915) >= 4) {
> Why do we need this restriction, not enough primes ?

Hardware restrictions (old gen only have power-of-two fence strides). We
are a doing a test using the GTT and real fence registers. It doesn't work
if we program them wrong ;)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre