drm/i915/gtt: Mark tlbs dirty on clear

Now when clearing ptes can modify upper level pdp's,
we need to mark them dirty so that they will be flushed
correctly.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1478006856-8313-1-git-send-email-mika.kuoppala@intel.com

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -707,6 +707,16 @@ static int gen8_48b_mm_switch(struct i915_hw_ppgtt *ppgtt,
 	return gen8_write_pdp(req, 0, px_dma(&ppgtt->pml4));
 }
 
+/* PDE TLBs are a pain to invalidate on GEN8+. When we modify
+ * the page table structures, we mark them dirty so that
+ * context switching/execlist queuing code takes extra steps
+ * to ensure that tlbs are flushed.
+ */
+static void mark_tlbs_dirty(struct i915_hw_ppgtt *ppgtt)
+{
+	ppgtt->pd_dirty_rings = INTEL_INFO(ppgtt->base.dev)->ring_mask;
+}
+
 /* Removes entries from a single page table, releasing it if it's empty.
  * Caller can use the return value to update higher-level entries.
  */
@@ -809,6 +819,8 @@ static bool gen8_ppgtt_clear_pdp(struct i915_address_space *vm,
 		}
 	}
 
+	mark_tlbs_dirty(ppgtt);
+
 	if (USES_FULL_48BIT_PPGTT(vm->dev) &&
 	    bitmap_empty(pdp->used_pdpes, I915_PDPES_PER_PDP(vm->dev))) {
 		free_pdp(vm->dev, pdp);
@@ -1283,16 +1295,6 @@ int __must_check alloc_gen8_temp_bitmaps(unsigned long **new_pds,
 	return -ENOMEM;
 }
 
-/* PDE TLBs are a pain to invalidate on GEN8+. When we modify
- * the page table structures, we mark them dirty so that
- * context switching/execlist queuing code takes extra steps
- * to ensure that tlbs are flushed.
- */
-static void mark_tlbs_dirty(struct i915_hw_ppgtt *ppgtt)
-{
-	ppgtt->pd_dirty_rings = INTEL_INFO(ppgtt->base.dev)->ring_mask;
-}
-
 static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm,
 				    struct i915_page_directory_pointer *pdp,
 				    uint64_t start,