diff --git a/tests/hwc/cnativewindow.c b/tests/hwc/cnativewindow.c
new file mode 100644
index 0000000..474ceec
--- /dev/null
+++ b/tests/hwc/cnativewindow.c
@@ -0,0 +1,578 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <errno.h>
+
+#include <pthread.h>
+
+#include <hardware/hardware.h>
+#include <hardware/gralloc.h>
+#include <hardware/hwcomposer.h>
+
+#include <system/window.h>
+#include <cutils/native_handle.h>
+
+// normalize and shorten type names
+typedef struct android_native_base_t aBase;
+typedef struct ANativeWindowBuffer aBuffer;
+typedef struct ANativeWindow aWindow;
+
+static int trace_level = 1;
+
+#define _TRACE(n,fmt...) \
+	do { if (trace_level >= n) fprintf(stderr, "CNW: " fmt); } while (0)
+
+#define ERROR(fmt...) _TRACE(0, fmt)
+#define INFO(fmt...) _TRACE(1, fmt)
+#define LOG(fmt...) _TRACE(2, fmt)
+#define TRACE(fmt...) _TRACE(3, fmt)
+
+#define QCT_WORKAROUND 1
+
+typedef struct CNativeBuffer {
+	aBuffer base;
+	struct CNativeBuffer *next;
+	struct CNativeBuffer *prev;
+	int ffd;
+} CNativeBuffer;
+
+typedef struct CNativeWindow {
+	aWindow base;
+
+	hwc_composer_device_1_t *hwc;
+	framebuffer_device_t *fb;
+	alloc_device_t *gr;
+
+	pthread_mutex_t lock;
+	pthread_cond_t cvar;
+
+	aBuffer *front;
+	aBuffer *spare;
+
+	CNativeBuffer free_buffer_queue;
+
+	unsigned width;
+	unsigned height;
+	unsigned xdpi;
+	unsigned ydpi;
+	unsigned format;
+
+	hwc_display_contents_1_t *dclist[HWC_NUM_DISPLAY_TYPES];
+
+	hwc_display_contents_1_t dc;
+	hwc_layer_1_t layer[4];
+} CNativeWindow;
+
+static inline CNativeBuffer *from_abuffer(aBuffer *buf) {
+	return (CNativeBuffer*) buf;
+}
+
+static CNativeBuffer *get_front(struct CNativeBuffer *queue) {
+	CNativeBuffer *buf = queue->next;
+	if (buf == queue)
+		return 0;
+	buf->next->prev = queue;
+	queue->next = buf->next;
+	buf->next = buf->prev = 0;
+	return buf;
+}
+
+static void put_front(struct CNativeBuffer *queue, aBuffer *_buf) {
+	struct CNativeBuffer *buf = (struct CNativeBuffer *) _buf;
+	buf->prev = queue;
+	buf->next = queue->next;
+	queue->next->prev = buf;
+	queue->next = buf;
+}
+
+static void put_back(struct CNativeBuffer *queue, aBuffer *_buf) {
+	struct CNativeBuffer *buf = (struct CNativeBuffer *) _buf;
+	buf->next = queue;
+	buf->prev = queue->prev;
+	queue->prev->next = buf;
+	queue->prev = buf;
+}
+
+static void cnw_inc_ref(aBase *base) { TRACE("buf %p ref++\n",base); }
+static void cnw_dec_ref(aBase *base) { TRACE("buf %p ref--\n",base); }
+
+static inline CNativeWindow *from_base(aWindow *base) {
+	return (CNativeWindow *) base;
+}
+
+static inline CNativeWindow *from_base_const(const aWindow *base) {
+	return (CNativeWindow *) base;
+}
+
+static int cnw_set_swap_interval(aWindow *base, int interval) {
+	CNativeWindow *win = from_base(base);
+	if (win->fb && win->fb->setSwapInterval)
+		return win->fb->setSwapInterval(win->fb, interval);
+	return 0;
+}
+
+static int cnw_dequeue_buffer1(aWindow *base, aBuffer **buf, int *ffd) {
+	CNativeWindow *win = from_base(base);
+	CNativeBuffer *cnb;
+
+	pthread_mutex_lock(&win->lock);
+
+	while ((cnb = get_front(&win->free_buffer_queue)) == 0) {
+		pthread_cond_wait(&win->cvar, &win->lock);
+	}
+
+	*ffd = cnb->ffd;
+	*buf = &cnb->base;
+	cnb->ffd = -1;
+	LOG("<< dequeue buffer %p %d\n", *buf, *ffd);
+
+	pthread_mutex_unlock(&win->lock);
+	return 0;
+}
+
+static int cnw_lock_buffer0(aWindow *base, aBuffer *buffer) {
+	return 0;
+}
+
+static void set_layer(hwc_layer_1_t *dl, aBuffer *buf, int ffd) {
+	int right = buf->width;
+	int bottom = buf->height;
+
+	dl->compositionType = HWC_FRAMEBUFFER;
+	dl->hints = 0;
+	dl->flags = 0;
+
+	dl->handle = buf->handle;
+	dl->transform = 0;
+	dl->blending = HWC_BLENDING_NONE;
+	dl->sourceCrop.left = 0;
+	dl->sourceCrop.top = 0;
+	dl->sourceCrop.right = right;
+	dl->sourceCrop.bottom = bottom;
+	dl->displayFrame.left = 0;
+	dl->displayFrame.top = 0;
+	dl->displayFrame.right = right;
+	dl->displayFrame.bottom = bottom;
+	dl->visibleRegionScreen.numRects = 1;
+	dl->visibleRegionScreen.rects = &dl->displayFrame;
+
+	dl->acquireFenceFd = ffd;
+	dl->releaseFenceFd = -1;
+}
+
+static void hwc_post(CNativeWindow *win, aBuffer *buf, int ffd) {
+	hwc_composer_device_1_t *hwc = win->hwc;
+	hwc_display_contents_1_t *dc = &(win->dc);
+	hwc_layer_1_t *dl = win->dc.hwLayers;
+	int r, i;
+
+	dc->retireFenceFd = -1;
+	dc->outbufAcquireFenceFd = -1;
+	dc->flags = HWC_GEOMETRY_CHANGED;
+	dc->numHwLayers = 1;
+
+	// some hwcomposers fail if these are NULL
+	dc->dpy = (void*) 0xdeadbeef;
+	dc->sur = (void*) 0xdeadbeef;
+
+	set_layer(&dl[0], buf, ffd);
+
+	if (QCT_WORKAROUND) {
+		set_layer(&dl[1], win->spare, -1);
+		dl[1].compositionType = HWC_FRAMEBUFFER_TARGET;
+		dc->numHwLayers++;
+	}
+
+	r = hwc->prepare(hwc, HWC_NUM_DISPLAY_TYPES, win->dclist);
+	if (r) {
+		ERROR("hwc->prepare failed r=%d\n",r);
+		return;
+	}
+
+//	for (i = 0; i < dc->numHwLayers; i++)
+//		LOG("dl[%d] ctype=0x%08x hints=0x%08x flags=0x%08x\n", i,
+//			dl[i].compositionType, dl[0].hints, dl[0].flags);
+
+	r = hwc->set(hwc, HWC_NUM_DISPLAY_TYPES, win->dclist);
+	if (r) {
+		ERROR("hwc->set failed, r=%d\n", r);
+		return;
+	}
+
+	if (dc->retireFenceFd != -1)
+		close(dc->retireFenceFd);
+	if (dl->releaseFenceFd != -1) {
+		CNativeBuffer *cnb = from_abuffer(buf);
+		cnb->ffd = dl->releaseFenceFd;
+	}
+	if (QCT_WORKAROUND)
+		if (dl[1].releaseFenceFd != -1)
+			close(dl[1].releaseFenceFd);
+}
+
+static int cnw_queue_buffer1(aWindow *base, aBuffer *buffer, int ffd) {
+	CNativeWindow *win = from_base(base);
+	int res;
+	LOG(">> queue buffer %p %d\n", buffer, ffd);
+	if (win->fb) {
+		res = win->fb->post(win->fb, buffer->handle);
+		if (ffd != -1)
+			close(ffd);
+	} else {
+		hwc_post(win, buffer, ffd);
+		res = 0;
+	}
+	pthread_mutex_lock(&win->lock);
+	if (win->front)
+		put_back(&win->free_buffer_queue, win->front);
+	win->front = buffer;
+	pthread_cond_signal(&win->cvar);
+	pthread_mutex_unlock(&win->lock);
+
+	return res;
+}
+
+static int cnw_cancel_buffer1(aWindow *base, aBuffer *buf, int ffd) {
+	CNativeWindow *win = from_base(base);
+	CNativeBuffer *cnb = from_abuffer(buf);
+	LOG("<< cancel buffer %p %d\n", buf, ffd);
+	cnb->ffd = ffd;
+	pthread_mutex_lock(&win->lock);
+	put_front(&win->free_buffer_queue, buf);
+	pthread_mutex_unlock(&win->lock);
+	return 0;
+}
+
+static int cnw_dequeue_buffer0(aWindow *base, aBuffer **buf) {
+	int ffd = -1;
+	int r;
+	r = cnw_dequeue_buffer1(base, buf, &ffd);
+	if (ffd != -1)
+		close(ffd);
+	return r;
+}
+
+static int cnw_queue_buffer0(aWindow *base, aBuffer *buf) {
+	return cnw_queue_buffer1(base, buf, -1);
+}
+
+static int cnw_cancel_buffer0(aWindow *base, aBuffer *buf) {
+	return cnw_cancel_buffer1(base, buf, -1);
+}
+
+static int cnw_query(const aWindow *base, int what, int *value) {
+	CNativeWindow *win = from_base_const(base);
+
+	switch (what) {
+	case NATIVE_WINDOW_WIDTH:
+	case NATIVE_WINDOW_DEFAULT_WIDTH:
+		*value = win->width;
+		TRACE("query window width: %d\n", *value);
+		return 0;
+	case NATIVE_WINDOW_HEIGHT:
+	case NATIVE_WINDOW_DEFAULT_HEIGHT:
+		*value = win->height;
+		TRACE("query window height: %d\n", *value);
+		return 0;
+	case NATIVE_WINDOW_FORMAT:
+		*value = win->format;
+		TRACE("query window format: %d\n", *value);
+		return 0;
+	case NATIVE_WINDOW_TRANSFORM_HINT:
+		TRACE("query transform hint: 0\n");
+		*value = 0;
+		return 0;
+	case NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS:
+		TRACE("query min undequeued buffers: 1\n");
+		*value = 1;
+		return 0;
+	default:
+		*value = 0;
+		ERROR("query %d unknown!\n", what);
+		return -EINVAL;
+	}
+}
+
+static int cnw_perform(aWindow *base, int op, ...) {
+	CNativeWindow *win = from_base(base);
+	va_list ap;
+	va_start(ap, op);
+
+	switch (op) {
+	case NATIVE_WINDOW_SET_USAGE:
+		TRACE("set usage %d\n", va_arg(ap,int));
+		return 0;
+	case NATIVE_WINDOW_CONNECT:
+	case NATIVE_WINDOW_DISCONNECT:
+	case NATIVE_WINDOW_API_CONNECT:
+	case NATIVE_WINDOW_API_DISCONNECT:
+		return 0;
+	case NATIVE_WINDOW_SET_BUFFERS_FORMAT:
+		TRACE("set buffers format %d\n", va_arg(ap,int));
+		return 0;
+	case NATIVE_WINDOW_SET_BUFFERS_TRANSFORM:
+		TRACE("set buffers transform %d\n", va_arg(ap,int));
+		return 0;
+	case NATIVE_WINDOW_SET_BUFFERS_TIMESTAMP:
+		TRACE("set buffers timestamp %lld\n", va_arg(ap,long long));
+		return 0;
+	case NATIVE_WINDOW_SET_SCALING_MODE:
+		TRACE("set scaling mode %d\n", va_arg(ap,int));
+		return 0;
+	case NATIVE_WINDOW_SET_BUFFERS_DIMENSIONS: {
+		int w = va_arg(ap,int);
+		int h = va_arg(ap,int);
+		if ((w == win->width) && (h == win->height)) {
+			TRACE("set buffers dimensions %d x %d\n", w, h);
+			return 0;
+		}
+		ERROR("cannot resize buffers to %d x %d\n", w, h);
+		return -1;
+	}
+	default:
+		ERROR("perform %d unknown!\n", op);
+		return -ENODEV;
+	}
+}
+
+static void hwc_invalidate(const struct hwc_procs *procs) {}
+static void hwc_vsync(const struct hwc_procs *procs, int disp, int64_t ts) {}
+static void hwc_hotplug(const struct hwc_procs *procs, int disp, int conn) {}
+
+struct hwc_procs hprocs = {
+	.invalidate = hwc_invalidate,
+	.vsync = hwc_vsync,
+	.hotplug = hwc_hotplug,
+};
+
+uint32_t attrs[] = {
+	HWC_DISPLAY_WIDTH,
+	HWC_DISPLAY_HEIGHT,
+	HWC_DISPLAY_VSYNC_PERIOD,
+	HWC_DISPLAY_DPI_X,
+	HWC_DISPLAY_DPI_Y,
+	HWC_DISPLAY_NO_ATTRIBUTE,
+};
+
+static int hwc_init(CNativeWindow *win) {
+	hw_module_t const* module;
+	hwc_composer_device_1_t *hwc;
+	unsigned i;
+	int r;
+	uint32_t configs[32];
+	uint32_t numconfigs = 32;
+	int32_t values[8];
+
+	if (hw_get_module(HWC_HARDWARE_MODULE_ID, &module) != 0) {
+		ERROR("cannot open hw composer module\n");
+		return -ENODEV;
+	}
+
+	if (hwc_open_1(module, &hwc)) {
+		ERROR("cannot open hwc device\n");
+		return -ENODEV;
+	}
+	win->hwc = hwc;
+
+	LOG("hwc version 0x%08x\n", hwc->common.version);
+
+	if ((hwc->common.version & 0xFFFF0000) < 0x01010000) {
+		ERROR("hwc version less than 1.1\n");
+		hwc_close_1(hwc);
+		return -ENODEV;
+	}
+
+	hwc->registerProcs(hwc, &hprocs);
+
+	if (hwc->getDisplayConfigs(hwc, 0, configs, &numconfigs)) {
+		ERROR("cannot get configs\n");
+		return -ENODEV;
+	}
+	for (i = 0; i < numconfigs; i++)
+		LOG("cfg[%d] = 0x%08x\n", i, configs[i]);
+
+	if ((r = hwc->getDisplayAttributes(hwc, 0, configs[0], attrs, values))) {
+		ERROR("cannot get attributes %d\n", r);
+		return -ENODEV;
+	}
+
+	win->width = values[0];
+	win->height = values[1];
+	win->xdpi = values[3];
+	win->ydpi = values[4];
+	win->format = HAL_PIXEL_FORMAT_RGBA_8888;
+
+	hwc->blank(hwc, 0, 0);
+
+	win->dclist[0] = &(win->dc);
+	return 0;
+}
+
+static aBuffer *cnw_alloc(CNativeWindow *win, unsigned format, unsigned usage) {
+	CNativeBuffer *cnb;
+	aBuffer *buf;
+	int err;
+
+	if (!(cnb = malloc(sizeof(CNativeBuffer))))
+		return 0;
+
+	buf = &cnb->base;
+	cnb->ffd = -1;
+
+	buf->common.magic = ANDROID_NATIVE_BUFFER_MAGIC;
+	buf->common.version = sizeof(aBuffer);
+	buf->common.incRef = cnw_inc_ref;
+	buf->common.decRef = cnw_dec_ref;
+
+	buf->width = win->width;
+	buf->height = win->height;
+	buf->format = format;
+	buf->usage = usage;
+
+	err = win->gr->alloc(win->gr, win->width, win->height,
+		format, usage, &buf->handle, &buf->stride);
+	if (err) {
+		ERROR("gralloc of %d x %d failed: err=%d\n",
+			win->width, win->height, err);
+		free(buf);
+		return 0;
+	}
+	INFO("alloc buffer %p %d x %d\n", buf, win->width, win->height);
+	return buf;
+}
+
+static int cnw_init(CNativeWindow *win) {
+	hw_module_t const* module;
+	framebuffer_device_t *fb = NULL;
+	alloc_device_t *gr;
+	int err, i, n;
+	unsigned usage, format;
+
+	memset(win, 0, sizeof(CNativeWindow));
+
+	win->free_buffer_queue.next = &(win->free_buffer_queue);
+	win->free_buffer_queue.prev = &(win->free_buffer_queue);
+
+	if (hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &module) != 0) {
+		ERROR("cannot open gralloc module\n");
+		return -ENODEV;
+	}
+
+	if (hwc_init(win)) {
+		ERROR("cannot open hwcomposer, trying legacy fb HAL\n");
+		err = framebuffer_open(module, &fb);
+		if (err) {
+			ERROR("cannot open fb HAL (%s)", strerror(-err));
+			return -ENODEV;
+		}
+		win->width = fb->width;
+		win->height = fb->height;
+		win->format = fb->format;
+		win->xdpi = fb->xdpi;
+		win->ydpi = fb->ydpi;
+		win->fb = fb;
+	}
+
+	INFO("display %d x %d fmt=%d\n",
+		win->width, win->height, win->format);
+
+	err = gralloc_open(module, &gr);
+	if (err) {
+		ERROR("couldn't open gralloc HAL (%s)", strerror(-err));
+		return -ENODEV;
+	}
+	win->gr = gr;
+
+	usage = GRALLOC_USAGE_HW_FB |
+		GRALLOC_USAGE_HW_COMPOSER |
+		GRALLOC_USAGE_HW_RENDER;
+
+	for (i = 0; i < 2; i++) {
+		aBuffer *buf = cnw_alloc(win, win->format, usage);
+		if (!buf)
+			return -ENOMEM;
+		put_back(&win->free_buffer_queue, buf);
+	}
+
+	if (!win->fb && QCT_WORKAROUND) {
+		win->spare = cnw_alloc(win, win->format, usage);
+		if (!win->spare)
+			return -ENOMEM;
+	}
+
+	// Disgusting, but we need to init these "const" fields
+	// and unlike C++ we can't use const_cast<>
+	*((float*) &win->base.xdpi) = win->xdpi;
+	*((float*) &win->base.ydpi) = win->ydpi;
+	*((int*) &win->base.minSwapInterval) = 1;
+	*((int*) &win->base.maxSwapInterval) = 1;
+
+	win->base.common.magic = ANDROID_NATIVE_WINDOW_MAGIC;
+	win->base.common.version = sizeof(aWindow);
+	win->base.common.incRef = cnw_inc_ref;
+	win->base.common.decRef = cnw_dec_ref;
+
+	win->base.setSwapInterval = cnw_set_swap_interval;
+	win->base.dequeueBuffer_DEPRECATED = cnw_dequeue_buffer0;
+	win->base.lockBuffer_DEPRECATED = cnw_lock_buffer0;
+	win->base.queueBuffer_DEPRECATED = cnw_queue_buffer0;
+	win->base.query = cnw_query;
+	win->base.perform = cnw_perform;
+	win->base.cancelBuffer_DEPRECATED = cnw_cancel_buffer0;
+	win->base.dequeueBuffer = cnw_dequeue_buffer1;
+	win->base.queueBuffer = cnw_queue_buffer1;
+	win->base.cancelBuffer = cnw_cancel_buffer1;
+
+	pthread_mutex_init(&win->lock, NULL);
+	pthread_cond_init(&win->cvar, NULL);
+
+	return 0;
+}
+
+void cnw_destroy(CNativeWindow *win) {
+	if (win->fb)
+		framebuffer_close(win->fb);
+	if (win->hwc)
+		hwc_close_1(win->hwc);
+	if (win->gr)
+		gralloc_close(win->gr);
+	free(win);
+}
+
+CNativeWindow *cnw_create(void) {
+	CNativeWindow *win;
+	char *x;
+	if ((x = getenv("CNWDEBUG")))
+		trace_level = atoi(x);
+	if (!(win = malloc(sizeof(CNativeWindow))))
+		return NULL;
+	if (cnw_init(win)) {
+		cnw_destroy(win);
+		return NULL;
+	}
+	return win;
+}
+
+void cnw_info(CNativeWindow *win, unsigned *w, unsigned *h, unsigned *fmt) {
+	*w = win->width;
+	*h = win->height;
+	*fmt = win->format;
+}
+