drm/i915: Convert partial ggtt vma to full ggtt if it spans the entire object

If we want to create a partial vma from a chunk that is the same size as
the object, create a normal ggtt vma instead. The benefit is that it
will match future requests for the normal ggtt.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160818161718.27187-24-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -1755,6 +1755,12 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
 			      (area->vm_end - area->vm_start) / PAGE_SIZE -
 			      view.params.partial.offset);
 
+		/* If the partial covers the entire object, just create a
+		 * normal VMA.
+		 */
+		if (chunk_size >= obj->base.size >> PAGE_SHIFT)
+			view.type = I915_GGTT_VIEW_NORMAL;
+
 		vma = i915_gem_object_ggtt_pin(obj, &view, 0, 0, PIN_MAPPABLE);
 	}
 	if (IS_ERR(vma)) {