diff --git a/tests/.gitignore b/tests/.gitignore
index 1466a7a..88a6405 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -104,6 +104,7 @@ gem_tiled_pread
 gem_tiled_pread_pwrite
 gem_tiled_swapping
 gem_tiled_wb
+gem_tiled_wc
 gem_tiling_max_stride
 gem_unfence_active_buffers
 gem_unref_active_buffers
diff --git a/tests/Makefile.sources b/tests/Makefile.sources
index 34c1899..74deec3 100644
--- a/tests/Makefile.sources
+++ b/tests/Makefile.sources
@@ -137,6 +137,7 @@ TESTS_progs = \
 	gem_tiled_pread_pwrite \
 	gem_tiled_swapping \
 	gem_tiled_wb \
+	gem_tiled_wc \
 	gem_tiling_max_stride \
 	gem_unfence_active_buffers \
 	gem_unref_active_buffers \
diff --git a/tests/gem_tiled_wc.c b/tests/gem_tiled_wc.c
new file mode 100644
index 0000000..633299e
--- /dev/null
+++ b/tests/gem_tiled_wc.c
@@ -0,0 +1,237 @@
+/*
+ * Copyright © 2009 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/** @file gem_tiled_wc.c
+ *
+ * This is a test of write-combining mmap's behavior on tiled objects
+ * with respect to the reported swizzling value.
+ *
+ * The goal is to exercise the complications that arise when using a linear
+ * view of a tiled object that is subject to hardware swizzling. This is
+ * useful to check that we are presenting the correct view of the object
+ * to userspace, and that userspace has to respect the swizzle.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/ioctl.h>
+#include "drm.h"
+#include "ioctl_wrappers.h"
+#include "drmtest.h"
+#include "intel_io.h"
+#include "intel_chipset.h"
+
+#define WIDTH 512
+#define HEIGHT 512
+#define SIZE (WIDTH*HEIGHT*sizeof(uint32_t))
+
+#define PAGE_SIZE 4096
+
+static int tile_width;
+static int tile_height;
+static int tile_size;
+
+static uint32_t
+create_bo(int fd)
+{
+	uint32_t handle;
+	uint32_t *data;
+	int i;
+
+	handle = gem_create(fd, SIZE);
+	gem_set_tiling(fd, handle, I915_TILING_X, WIDTH * sizeof(uint32_t));
+
+	/* Fill the BO with dwords starting at start_val */
+	data = gem_mmap__wc(fd, handle, 0, SIZE, PROT_READ | PROT_WRITE);
+	for (i = 0; i < WIDTH*HEIGHT; i++)
+		data[i] = i;
+	munmap(data, SIZE);
+
+	return handle;
+}
+
+static int
+swizzle_bit(int bit, int offset)
+{
+	return (offset & (1 << bit)) >> (bit - 6);
+}
+
+/* Translate from a swizzled offset in the tiled buffer to the corresponding
+ * value from the original linear buffer.
+ */
+static uint32_t
+calculate_expected(int offset)
+{
+	int tile_off = offset & (tile_size - 1);
+	int tile_base = offset & -tile_size;
+	int tile_index = tile_base / tile_size;
+	int tiles_per_row = 4*WIDTH / tile_width;
+
+	/* base x,y values from the tile (page) index. */
+	int base_y = tile_index / tiles_per_row * tile_height;
+	int base_x = tile_index % tiles_per_row * (tile_width/4);
+
+	/* x, y offsets within the tile */
+	int tile_y = tile_off / tile_width;
+	int tile_x = (tile_off % tile_width) / 4;
+
+	igt_debug("%3d, %3d, %3d,%3d\n", base_x, base_y, tile_x, tile_y);
+	return (base_y + tile_y) * WIDTH + base_x + tile_x;
+}
+
+static void
+get_tiling(int fd, uint32_t handle, uint32_t *tiling, uint32_t *swizzle)
+{
+	struct drm_i915_gem_get_tiling2 {
+		uint32_t handle;
+		uint32_t tiling_mode;
+		uint32_t swizzle_mode;
+		uint32_t phys_swizzle_mode;
+	} arg;
+#define DRM_IOCTL_I915_GEM_GET_TILING2	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_GET_TILING, struct drm_i915_gem_get_tiling2)
+
+	memset(&arg, 0, sizeof(arg));
+	arg.handle = handle;
+
+	do_or_die(drmIoctl(fd, DRM_IOCTL_I915_GEM_GET_TILING2, &arg));
+	igt_require(arg.phys_swizzle_mode == arg.swizzle_mode);
+
+	*tiling = arg.tiling_mode;
+	*swizzle = arg.swizzle_mode;
+}
+
+igt_simple_main
+{
+	int fd;
+	int i, iter = 100;
+	uint32_t tiling, swizzle;
+	uint32_t handle;
+
+	fd = drm_open_any();
+	igt_require_mmap_wc(fd);
+
+	handle = create_bo(fd);
+	get_tiling(fd, handle, &tiling, &swizzle);
+
+	if (IS_GEN2(intel_get_drm_devid(fd))) {
+		tile_height = 16;
+		tile_width = 128;
+		tile_size = 2048;
+	} else {
+		tile_height = 8;
+		tile_width = 512;
+		tile_size = PAGE_SIZE;
+	}
+
+	/* Read a bunch of random subsets of the data and check that they come
+	 * out right.
+	 */
+	for (i = 0; i < iter; i++) {
+		int size = WIDTH * HEIGHT * 4;
+		int offset = (random() % size) & ~3;
+		int len = (random() % size) & ~3;
+		int first_page, last_page;
+		uint32_t *linear;
+		int j;
+
+		if (len == 0)
+			len = 4;
+
+		if (offset + len > size)
+			len = size - offset;
+
+		if (i == 0) {
+			offset = 0;
+			len = size;
+		}
+
+		first_page = offset & ~(PAGE_SIZE-1);
+		last_page = (offset + len + PAGE_SIZE) & ~(PAGE_SIZE-1);
+		offset -= first_page;
+
+		linear = gem_mmap__wc(fd, handle, first_page, last_page - first_page, PROT_READ);
+		igt_assert(linear);
+
+		/* Translate from offsets in the read buffer to the swizzled
+		 * address that it corresponds to.  This is the opposite of
+		 * what Mesa does (calculate offset to be read given the linear
+		 * offset it's looking for).
+		 */
+		for (j = offset; j < offset + len; j += 4) {
+			uint32_t expected_val, found_val;
+			int swizzled_offset;
+			const char *swizzle_str;
+
+			switch (swizzle) {
+			case I915_BIT_6_SWIZZLE_NONE:
+				swizzled_offset = j;
+				swizzle_str = "none";
+				break;
+			case I915_BIT_6_SWIZZLE_9:
+				swizzled_offset = j ^
+					swizzle_bit(9, j);
+				swizzle_str = "bit9";
+				break;
+			case I915_BIT_6_SWIZZLE_9_10:
+				swizzled_offset = j ^
+					swizzle_bit(9, j) ^
+					swizzle_bit(10, j);
+				swizzle_str = "bit9^10";
+				break;
+			case I915_BIT_6_SWIZZLE_9_11:
+				swizzled_offset = j ^
+					swizzle_bit(9, j) ^
+					swizzle_bit(11, j);
+				swizzle_str = "bit9^11";
+				break;
+			case I915_BIT_6_SWIZZLE_9_10_11:
+				swizzled_offset = j ^
+					swizzle_bit(9, j) ^
+					swizzle_bit(10, j) ^
+					swizzle_bit(11, j);
+				swizzle_str = "bit9^10^11";
+				break;
+			default:
+				igt_skip("unknown swizzling");
+				break;
+			}
+			expected_val = calculate_expected(swizzled_offset);
+			found_val = linear[j / 4];
+			igt_assert_f(expected_val == found_val,
+				     "Bad read [%d]: %d instead of %d at 0x%08x "
+				     "for read from 0x%08x to 0x%08x, swizzle=%s\n",
+				     i, found_val, expected_val, j,
+				     offset, offset + len,
+				     swizzle_str);
+			munmap(linear, last_page - first_page);
+		}
+	}
+
+	close(fd);
+}
