diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index aad3d6ffbabc0c8db635ee94e40a3e67942cb171..4b91cc18eef38f60afe3cff07957a93247b2363a 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -457,8 +457,9 @@ static struct i915_page_directory *alloc_pd_single(void)
 }
 
 /* Broadwell Page Directory Pointer Descriptors */
-static int gen8_write_pdp(struct intel_engine_cs *ring, unsigned entry,
-			   uint64_t val)
+static int gen8_write_pdp(struct intel_engine_cs *ring,
+			  unsigned entry,
+			  dma_addr_t addr)
 {
 	int ret;
 
@@ -470,10 +471,10 @@ static int gen8_write_pdp(struct intel_engine_cs *ring, unsigned entry,
 
 	intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
 	intel_ring_emit(ring, GEN8_RING_PDP_UDW(ring, entry));
-	intel_ring_emit(ring, (u32)(val >> 32));
+	intel_ring_emit(ring, upper_32_bits(addr));
 	intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
 	intel_ring_emit(ring, GEN8_RING_PDP_LDW(ring, entry));
-	intel_ring_emit(ring, (u32)(val));
+	intel_ring_emit(ring, lower_32_bits(addr));
 	intel_ring_advance(ring);
 
 	return 0;
@@ -484,12 +485,12 @@ static int gen8_mm_switch(struct i915_hw_ppgtt *ppgtt,
 {
 	int i, ret;
 
-	/* bit of a hack to find the actual last used pd */
-	int used_pd = ppgtt->num_pd_entries / I915_PDES;
-
-	for (i = used_pd - 1; i >= 0; i--) {
-		dma_addr_t addr = ppgtt->pdp.page_directory[i]->daddr;
-		ret = gen8_write_pdp(ring, i, addr);
+	for (i = GEN8_LEGACY_PDPES - 1; i >= 0; i--) {
+		struct i915_page_directory *pd = ppgtt->pdp.page_directory[i];
+		dma_addr_t pd_daddr = pd ? pd->daddr : ppgtt->scratch_pd->daddr;
+		/* The page directory might be NULL, but we need to clear out
+		 * whatever the previous context might have used. */
+		ret = gen8_write_pdp(ring, i, pd_daddr);
 		if (ret)
 			return ret;
 	}
@@ -664,6 +665,7 @@ static void gen8_ppgtt_free(struct i915_hw_ppgtt *ppgtt)
 		unmap_and_free_pd(ppgtt->pdp.page_directory[i]);
 	}
 
+	unmap_and_free_pd(ppgtt->scratch_pd);
 	unmap_and_free_pt(ppgtt->scratch_pt, ppgtt->base.dev);
 }
 
@@ -880,12 +882,20 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
 	if (IS_ERR(ppgtt->scratch_pt))
 		return PTR_ERR(ppgtt->scratch_pt);
 
+	ppgtt->scratch_pd = alloc_pd_single();
+	if (IS_ERR(ppgtt->scratch_pd))
+		return PTR_ERR(ppgtt->scratch_pd);
+
 	gen8_initialize_pt(&ppgtt->base, ppgtt->scratch_pt);
+	gen8_initialize_pd(&ppgtt->base, ppgtt->scratch_pd);
 
 	/* 1. Do all our allocations for page directories and page tables. */
 	ret = gen8_ppgtt_alloc(ppgtt, ppgtt->base.start, ppgtt->base.total);
-	if (ret)
+	if (ret) {
+		unmap_and_free_pd(ppgtt->scratch_pd);
+		unmap_and_free_pt(ppgtt->scratch_pt, ppgtt->base.dev);
 		return ret;
+	}
 
 	/*
 	 * 2. Create DMA mappings for the page directories and page tables.
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 63fda82452ec98e83014ee61ee83c1247f901696..acf8ed7f86ef1d781caf0d10d50c8271a9c296a5 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -322,6 +322,7 @@ struct i915_hw_ppgtt {
 	};
 
 	struct i915_page_table *scratch_pt;
+	struct i915_page_directory *scratch_pd;
 
 	struct drm_i915_file_private *file_priv;