[PATCH] drm/i915: fix sanitize_enable_ppgtt for full PPGTT

[Jesse Barnes <jbarnes@virtuousgeek.org>]

Apparently trinary logic is hard.  We were falling through all the forced
cases and simply enabling aliasing PPGTT or not based on hardware,
rather than full PPGTT if available.

References: https://bugs.freedesktop.org/show_bug.cgi?id=80083
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index a4153ee..86521a7 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -69,7 +69,13 @@ static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
 		return 0;
 	}
 
-	return HAS_ALIASING_PPGTT(dev) ? 1 : 0;
+	/* Fall through to auto-detect */
+	if (HAS_PPGTT(dev))
+		return 2;
+	else if (HAS_ALIASING_PPGTT(dev))
+		return 1;
+
+	return 0;
 }
 
 
-- 
1.9.1