diff --git a/helpers.c b/helpers.c
index f648d5a4..9d791ea1 100644
--- a/helpers.c
+++ b/helpers.c
@@ -651,3 +651,40 @@ bool drv_has_modifier(const uint64_t *list, uint32_t count, uint64_t modifier)
 
 	return false;
 }
+
+const u_int16_t ytile_width = 16;
+const u_int16_t ytile_heigth = 32;
+void one_ytile_to_linear(char *src, char *dst, u_int16_t x, u_int16_t y, u_int16_t width, u_int16_t height, u_int16_t offset)
+{
+	// x and y follow linear
+    u_int32_t count = x + y * width/ytile_width;
+
+    for (int j = 0; j < ytile_width * ytile_heigth; j += ytile_width) {
+        memcpy(dst + offset + width * ytile_heigth * y + width * j / ytile_width + x * ytile_width,
+            src + offset + j + ytile_width * ytile_heigth * count, ytile_width);
+    }
+}
+
+void * ytiled_to_linear(struct bo_metadata meta, void * src)
+{
+	void* dst = malloc(meta.total_size);
+	if (NULL == dst) return NULL;
+
+	memset(dst, 0, meta.total_size);
+
+	u_int16_t height = meta.sizes[0] / meta.strides[0];
+	// Y
+	for (u_int16_t x = 0; x < meta.strides[0]/ytile_width; x++) {
+		for (u_int16_t y = 0; y < height/ytile_heigth; y++) {
+			one_ytile_to_linear(src, dst, x, y, meta.strides[0], height, 0);
+		}
+	}
+	// UV
+	for (u_int16_t x = 0; x < meta.strides[0]/ytile_width; x++) {
+		for (u_int16_t y = 0; y < ceil((double)height/ytile_heigth/2); y++) {
+			one_ytile_to_linear(src, dst, x, y, meta.strides[0], height, meta.sizes[0]);
+		}
+	}
+
+	return dst;
+}
diff --git a/helpers.h b/helpers.h
index 19d0fd74..e6c8e9bd 100644
--- a/helpers.h
+++ b/helpers.h
@@ -7,6 +7,7 @@
 #ifndef HELPERS_H
 #define HELPERS_H
 
+#include <math.h>
 #include <stdbool.h>
 
 #include "drv.h"
@@ -42,4 +43,8 @@ int drv_modify_linear_combinations(struct driver *drv);
 uint64_t drv_pick_modifier(const uint64_t *modifiers, uint32_t count,
 			   const uint64_t *modifier_order, uint32_t order_count);
 bool drv_has_modifier(const uint64_t *list, uint32_t count, uint64_t modifier);
+
+void one_ytile_to_linear(char *src, char *dst, u_int16_t x, u_int16_t y,
+						u_int16_t width, u_int16_t height, u_int16_t offset);
+void *ytiled_to_linear(struct bo_metadata meta, void * src);
 #endif
diff --git a/i915.c b/i915.c
index 9c68d5c0..e6732376 100644
--- a/i915.c
+++ b/i915.c
@@ -967,6 +967,16 @@ static void *i915_bo_map(struct bo *bo, struct vma *vma, size_t plane, uint32_t
 		/* And map it */
 		addr = mmap(0, bo->meta.total_size, PROT_READ | PROT_WRITE, MAP_SHARED, bo->drv->fd,
 			    mmap_arg.offset);
+
+		// TODO: GEM_MMAP_OFFSET cannot convert ytiled to linear, we have to convert it manually.
+		void* tmp_addr = ytiled_to_linear(bo->meta, addr);
+
+		if (NULL != tmp_addr) {
+			// XXX: The releasing address when unmap is the one returned by mmap.
+			// So we need to copy data back to addr.
+			memcpy(addr, tmp_addr, bo->meta.total_size);
+			free(tmp_addr);
+		}
 	} else if (bo->meta.tiling == I915_TILING_NONE) {
 		struct drm_i915_gem_mmap gem_map;
 		memset(&gem_map, 0, sizeof(gem_map));