drm/i915: Zap the GTT mapping when transitioning from untiled to tiled.

As of 52dc7d32b88156248167864f77a9026abe27b432, we could leave an old
linear GTT mapping in place, so that apps trying to GTT-mapped write in
tiled data wouldn't get the fence added, and garbage would get displayed.

Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index daeae62e1c28..a2d527b22ec4 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -521,6 +521,12 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
                         goto err;
                 }
 
+                /* If we've changed tiling, GTT-mappings of the object
+                 * need to re-fault to ensure that the correct fence register
+                 * setup is in place.
+                 */
+                i915_gem_release_mmap(obj);
+
                 obj_priv->tiling_mode = args->tiling_mode;
                 obj_priv->stride = args->stride;
         }