diff --git a/Android.mk b/Android.mk
index b2e9caf..a35de91 100644
--- a/Android.mk
+++ b/Android.mk
@@ -33,3 +33,8 @@
 LOCAL_MODULE:= libhardware
 
 include $(BUILD_SHARED_LIBRARY)
+
+include $(addsuffix /Android.mk, $(addprefix $(LOCAL_PATH)/, \
+			modules/gralloc \
+		))
+		
\ No newline at end of file
diff --git a/hardware.c b/hardware.c
index cc68602..ffc9a25 100644
--- a/hardware.c
+++ b/hardware.c
@@ -62,7 +62,7 @@
 {
     int status;
     void *handle;
-    const struct hw_module_t *hmi;
+    struct hw_module_t *hmi;
     char path[PATH_MAX];
 
     /* Construct the path. */
@@ -78,14 +78,14 @@
     handle = dlopen(path, RTLD_NOW);
     if (handle == NULL) {
         char const *err_str = dlerror();
-        LOGW("load: module=%s error=%s", path, err_str);
+        //LOGW("load: module=%s error=%s", path, err_str);
         status = -EINVAL;
         goto done;
     }
 
     /* Get the address of the struct hal_module_info. */
     const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
-    hmi = (const struct hw_module_t *)dlsym(handle, sym);
+    hmi = (struct hw_module_t *)dlsym(handle, sym);
     if (hmi == NULL) {
         char const *err_str = dlerror();
         LOGE("load: couldn't find symbol %s", sym);
@@ -99,6 +99,8 @@
         status = -EINVAL;
         goto done;
     }
+    
+    hmi->dso = handle;
 
     /* success */
     status = 0;
diff --git a/include/hardware/gralloc.h b/include/hardware/gralloc.h
new file mode 100644
index 0000000..d88591f
--- /dev/null
+++ b/include/hardware/gralloc.h
@@ -0,0 +1,320 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+
+#ifndef ANDROID_GRALLOC_INTERFACE_H
+#define ANDROID_GRALLOC_INTERFACE_H
+
+#include <cutils/native_handle.h>
+
+#include <hardware/hardware.h>
+
+#include <stdint.h>
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+/**
+ * The id of this module
+ */
+#define GRALLOC_HARDWARE_MODULE_ID "gralloc"
+
+/**
+ * Name of the graphics device to open
+ */
+
+#define GRALLOC_HARDWARE_FB0 "fb0"
+#define GRALLOC_HARDWARE_GPU0 "gpu0"
+
+enum {
+    /* buffer is never read in software */
+    GRALLOC_USAGE_SW_READ_NEVER   = 0x00000000,
+    /* buffer is rarely read in software */
+    GRALLOC_USAGE_SW_READ_RARELY  = 0x00000002,
+    /* buffer is often read in software */
+    GRALLOC_USAGE_SW_READ_OFTEN   = 0x00000003,
+    /* mask for the software read values */
+    GRALLOC_USAGE_SW_READ_MASK    = 0x0000000F,
+    
+    /* buffer is never written in software */
+    GRALLOC_USAGE_SW_WRITE_NEVER  = 0x00000000,
+    /* buffer is never written in software */
+    GRALLOC_USAGE_SW_WRITE_RARELY = 0x00000020,
+    /* buffer is never written in software */
+    GRALLOC_USAGE_SW_WRITE_OFTEN  = 0x00000030,
+    /* mask for the software write values */
+    GRALLOC_USAGE_SW_WRITE_MASK   = 0x000000F0,
+
+    /* buffer will be used as an OpenGL ES texture */
+    GRALLOC_USAGE_HW_TEXTURE      = 0x00000100,
+    /* buffer will be used as an OpenGL ES render target */
+    GRALLOC_USAGE_HW_RENDER       = 0x00000200,
+    /* buffer will be used by the 2D hardware blitter */
+    GRALLOC_USAGE_HW_2D           = 0x00000C00,
+    /* buffer will be used with the framebuffer device */
+    GRALLOC_USAGE_HW_FB           = 0x00001000,
+    /* mask for the software usage bit-mask */
+    GRALLOC_USAGE_HW_MASK         = 0x00001F00,
+};
+
+/*****************************************************************************/
+
+typedef const native_handle* buffer_handle_t;
+
+/**
+ * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
+ * and the fields of this data structure must begin with hw_module_t
+ * followed by module specific information.
+ */
+struct gralloc_module_t {
+    struct hw_module_t common;
+    
+    
+    /*
+     * (*registerBuffer)() must be called before a buffer_handle_t that has not
+     * been created with (*alloc_device_t::alloc)() can be used.
+     * 
+     * This is intended to be used with buffer_handle_t's that have been
+     * received in this process through IPC.
+     * 
+     * This function checks that the handle is indeed a valid one and prepares
+     * it for use with (*lock)() and (*unlock)().
+     * 
+     * It is not necessary to call (*registerBuffer)() on a handle created 
+     * with (*alloc_device_t::alloc)().
+     * 
+     * returns an error if this buffer_handle_t is not valid.
+     */
+    int (*registerBuffer)(struct gralloc_module_t const* module,
+            buffer_handle_t handle);
+
+    /*
+     * (*unregisterBuffer)() is called once this handle is no longer needed in
+     * this process. After this call, it is an error to call (*lock)(),
+     * (*unlock)(), or (*registerBuffer)().
+     * 
+     * This function doesn't close or free the handle itself; this is done
+     * by other means, usually through libcutils's native_handle_close() and
+     * native_handle_free(). 
+     * 
+     * It is an error to call (*unregisterBuffer)() on a buffer that wasn't
+     * explicitly registered first.
+     */
+    int (*unregisterBuffer)(struct gralloc_module_t const* module,
+            buffer_handle_t handle);
+    
+    /*
+     * The (*lock)() method is called before a buffer is accessed for the 
+     * specified usage. This call may block, for instance if the h/w needs
+     * to finish rendering or if CPU caches need to be synchronized.
+     * 
+     * The caller promises to modify only pixels in the area specified 
+     * by (l,t,w,h).
+     * 
+     * The content of the buffer outside of the specified area is NOT modified
+     * by this call.
+     *
+     * If usage specifies GRALLOC_USAGE_SW_*, vaddr is filled with the address
+     * of the buffer in virtual memory.
+     *
+     * THREADING CONSIDERATIONS:
+     *
+     * It is legal for several different threads to lock a buffer from 
+     * read access, none of the threads are blocked.
+     * 
+     * However, locking a buffer simultaneously for write or read/write is
+     * undefined, but:
+     * - shall not result in termination of the process
+     * - shall not block the caller
+     * It is acceptable to return an error or to leave the buffer's content
+     * into an indeterminate state.
+     *
+     * If the buffer was created with a usage mask incompatible with the
+     * requested usage flags here, -EINVAL is returned. 
+     * 
+     */
+    
+    int (*lock)(struct gralloc_module_t const* module,
+            buffer_handle_t handle, int usage,
+            int l, int t, int w, int h,
+            void** vaddr);
+
+    
+    /*
+     * The (*unlock)() method must be called after all changes to the buffer
+     * are completed.
+     */
+    
+    int (*unlock)(struct gralloc_module_t const* module,
+            buffer_handle_t handle);
+
+};
+
+/*****************************************************************************/
+
+/**
+ * Every device data structure must begin with hw_device_t
+ * followed by module specific public methods and attributes.
+ */
+
+struct alloc_device_t {
+    struct hw_device_t common;
+
+    /* 
+     * (*alloc)() Allocates a buffer in graphic memory with the requested
+     * parameters and returns a buffer_handle_t and the stride in pixels to
+     * allow the implementation to satisfy hardware constraints on the width
+     * of a pixmap (eg: it may have to be multiple of 8 pixels). 
+     * The CALLER TAKES OWNERSHIP of the buffer_handle_t.
+     * 
+     * Returns 0 on success or -errno on error.
+     */
+    
+    int (*alloc)(struct alloc_device_t* dev,
+            int w, int h, int format, int usage,
+            buffer_handle_t* handle, int* stride);
+
+    /*
+     * (*free)() Frees a previously allocated buffer. 
+     * Behavior is undefined if the buffer is still mapped in any process,
+     * but shall not result in termination of the program or security breaches
+     * (allowing a process to get access to another process' buffers).
+     * THIS FUNCTION TAKES OWNERSHIP of the buffer_handle_t which becomes
+     * invalid after the call. 
+     * 
+     * Returns 0 on success or -errno on error.
+     */
+    int (*free)(struct alloc_device_t* dev,
+            buffer_handle_t handle);
+
+};
+
+
+struct framebuffer_device_t {
+    struct hw_device_t common;
+
+    /* flags describing some attributes of the framebuffer */
+    const uint32_t  flags;
+    
+    /* dimensions of the framebuffer in pixels */
+    const uint32_t  width;
+    const uint32_t  height;
+
+    /* frambuffer stride in pixels */
+    const int       stride;
+    
+    /* framebuffer pixel format */
+    const int       format;
+    
+    /* resolution of the framebuffer's display panel in pixel per inch*/
+    const float     xdpi;
+    const float     ydpi;
+
+    /* framebuffer's display panel refresh rate in frames per second */
+    const float     fps;
+
+    /* min swap interval supported by this framebuffer */
+    const int       minSwapInterval;
+
+    /* max swap interval supported by this framebuffer */
+    const int       maxSwapInterval;
+
+    int reserved[8];
+    
+    /* 
+     * requests a specific swap-interval (same definition than EGL) 
+     * 
+     * Returns 0 on success or -errno on error.
+     */
+    int (*setSwapInterval)(struct framebuffer_device_t* window,
+            int interval);
+
+    /*
+     * This hook is OPTIONAL.
+     * 
+     * It is non NULL If the framebuffer driver supports "update-on-demand" 
+     * and the given rectangle is the area of the screen that gets 
+     * updated during (*post)().
+     * 
+     * This is useful on devices that are able to DMA only a portion of
+     * the screen to the display panel, upon demand -- as opposed to
+     * constantly refreshing the panel 60 times per second, for instance.
+     * 
+     * Only the area defined by this rectangle is guranteed to be valid, that
+     * is, the driver is not allowed to post anything outside of this
+     * rectangle. 
+     * 
+     * The rectangle evaluated during (*post)() and specifies which area
+     * of the buffer passed in (*post)() shall to be posted.
+     * 
+     * return -EINVAL if width or height <=0, or if left or top < 0 
+     */
+    int (*setUpdateRect)(struct framebuffer_device_t* window,
+            int left, int top, int width, int height);
+    
+    /*
+     * Post <buffer> to the display (display it on the screen)
+     * The buffer must have been allocated with the 
+     *   GRALLOC_USAGE_HW_FB usage flag.
+     * buffer must be the same width and height as the display and must NOT
+     * be locked.
+     * 
+     * The buffer is shown during the next VSYNC. 
+     * 
+     * If the same buffer is posted again (possibly after some other buffer),
+     * post() will block until the the first post is completed.
+     *
+     * Internally, post() is expected to lock the buffer so that a 
+     * subsequent call to gralloc_module_t::(*lock)() with USAGE_RENDER or
+     * USAGE_*_WRITE will block until it is safe; that is typically once this
+     * buffer is shown and another buffer has been posted.
+     *
+     * Returns 0 on success or -errno on error.
+     */
+    int (*post)(struct framebuffer_device_t* dev, buffer_handle_t buffer);
+
+    void* reserved_proc[8];
+};
+
+
+/** convenience API for opening and closing a supported device */
+
+static inline int gralloc_open(const struct hw_module_t* module, 
+        struct alloc_device_t** device) {
+    return module->methods->open(module, 
+            GRALLOC_HARDWARE_GPU0, (struct hw_device_t**)device);
+}
+
+static inline int gralloc_close(struct alloc_device_t* device) {
+    return device->common.close(&device->common);
+}
+
+
+static inline int framebuffer_open(const struct hw_module_t* module, 
+        struct framebuffer_device_t** device) {
+    return module->methods->open(module, 
+            GRALLOC_HARDWARE_FB0, (struct hw_device_t**)device);
+}
+
+static inline int framebuffer_close(struct framebuffer_device_t* device) {
+    return device->common.close(&device->common);
+}
+
+
+__END_DECLS
+
+#endif  // ANDROID_ALLOC_INTERFACE_H
diff --git a/include/hardware/hardware.h b/include/hardware/hardware.h
index 5325744..c8dc6f6 100644
--- a/include/hardware/hardware.h
+++ b/include/hardware/hardware.h
@@ -20,13 +20,18 @@
 #include <stdint.h>
 #include <sys/cdefs.h>
 
+#include <cutils/native_handle.h>
+
 __BEGIN_DECLS
 
 /*
  * Value for the hw_module_t.tag field
  */
-#define HARDWARE_MODULE_TAG 'HWMT'
-#define HARDWARE_DEVICE_TAG 'HWDT'
+
+#define MAKE_TAG_CONSTANT(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D))
+
+#define HARDWARE_MODULE_TAG MAKE_TAG_CONSTANT('H', 'W', 'M', 'T')
+#define HARDWARE_DEVICE_TAG MAKE_TAG_CONSTANT('H', 'W', 'D', 'T')
 
 struct hw_module_t;
 struct hw_module_methods_t;
@@ -58,9 +63,12 @@
 
     /** Modules methods */
     struct hw_module_methods_t* methods;
-    
+
+    /** module's dso */
+    void* dso;
+
     /** padding to 128 bytes, reserved for future use */
-    uint32_t reserved[32-6];
+    uint32_t reserved[32-7];
 };
 
 struct hw_module_methods_t {
@@ -91,7 +99,7 @@
 };
 
 /**
- * Name of the hal_module_info 
+ * Name of the hal_module_info
  */
 #define HAL_MODULE_INFO_SYM         HMI
 
diff --git a/modules/gralloc/Android.mk b/modules/gralloc/Android.mk
new file mode 100644
index 0000000..1603f2d
--- /dev/null
+++ b/modules/gralloc/Android.mk
@@ -0,0 +1,27 @@
+# Copyright (C) 2008 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.
+
+
+LOCAL_PATH := $(call my-dir)
+
+# HAL module implemenation, not prelinked and stored in
+# hw/<OVERLAY_HARDWARE_MODULE_ID>.<ro.product.board>.so
+include $(CLEAR_VARS)
+LOCAL_PRELINK_MODULE := false
+LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
+LOCAL_SHARED_LIBRARIES := liblog libcutils
+LOCAL_SRC_FILES := gralloc.cpp mapper.cpp framebuffer.cpp
+LOCAL_MODULE := gralloc.default
+LOCAL_CFLAGS:= -DLOG_TAG=\"gralloc\"
+include $(BUILD_SHARED_LIBRARY)
diff --git a/modules/gralloc/framebuffer.cpp b/modules/gralloc/framebuffer.cpp
new file mode 100644
index 0000000..d885ae8
--- /dev/null
+++ b/modules/gralloc/framebuffer.cpp
@@ -0,0 +1,370 @@
+/*
+ * Copyright (C) 2008 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 <sys/mman.h>
+
+#include <dlfcn.h>
+
+#include <cutils/ashmem.h>
+#include <cutils/log.h>
+
+#include <hardware/hardware.h>
+#include <hardware/gralloc.h>
+
+#include <fcntl.h>
+#include <errno.h>
+
+#include <cutils/log.h>
+#include <cutils/atomic.h>
+
+#if HAVE_ANDROID_OS
+#include <linux/fb.h>
+#endif
+
+#include "gralloc_priv.h"
+
+/*****************************************************************************/
+
+// should be a build option
+#define SUPPORTS_UPDATE_ON_DEMAND   1
+
+#define NUM_BUFFERS 2
+
+
+enum {
+    PAGE_FLIP = 0x00000001,
+    LOCKED = 0x00000002
+};
+
+struct fb_context_t {
+    framebuffer_device_t  device;
+};
+
+/*****************************************************************************/
+
+static int fb_setSwapInterval(struct framebuffer_device_t* dev,
+            int interval)
+{
+    fb_context_t* ctx = (fb_context_t*)dev;
+    if (interval < dev->minSwapInterval || interval > dev->maxSwapInterval)
+        return -EINVAL;
+    // FIXME: implement fb_setSwapInterval
+    return 0;
+}
+
+static int fb_setUpdateRect(struct framebuffer_device_t* dev,
+        int l, int t, int w, int h)
+{
+    if (((w|h) <= 0) || ((l|t)<0))
+        return -EINVAL;
+        
+    fb_context_t* ctx = (fb_context_t*)dev;
+    private_module_t* m = reinterpret_cast<private_module_t*>(
+            dev->common.module);
+    m->info.reserved[0] = 0x54445055; // "UPDT";
+    m->info.reserved[1] = (uint16_t)l | ((uint32_t)t << 16);
+    m->info.reserved[2] = (uint16_t)(l+w) | ((uint32_t)(t+h) << 16);
+    return 0;
+}
+
+static int fb_post(struct framebuffer_device_t* dev, buffer_handle_t buffer)
+{
+    if (private_handle_t::validate(buffer) < 0)
+        return -EINVAL;
+
+    fb_context_t* ctx = (fb_context_t*)dev;
+
+    private_handle_t const* hnd = reinterpret_cast<private_handle_t const*>(buffer);
+    private_module_t* m = reinterpret_cast<private_module_t*>(
+            dev->common.module);
+    
+    if (m->currentBuffer) {
+        m->base.unlock(&m->base, m->currentBuffer);
+        m->currentBuffer = 0;
+    }
+
+    if (hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER) {
+
+        m->base.lock(&m->base, buffer, 
+                private_module_t::PRIV_USAGE_LOCKED_FOR_POST, 
+                0, 0, m->info.xres, m->info.yres, NULL);
+
+        const size_t offset = hnd->base - m->framebuffer->base;
+        m->info.activate = FB_ACTIVATE_VBL;
+        m->info.yoffset = offset / m->finfo.line_length;
+        if (ioctl(m->framebuffer->fd, FBIOPUT_VSCREENINFO, &m->info) == -1) {
+            LOGE("FBIOPUT_VSCREENINFO failed");
+            m->base.unlock(&m->base, buffer); 
+            return -errno;
+        }
+        m->currentBuffer = buffer;
+        
+    } else {
+        // If we can't do the page_flip, just copy the buffer to the front 
+        // FIXME: use copybit HAL instead of memcpy
+        
+        void* fb_vaddr;
+        void* buffer_vaddr;
+        
+        m->base.lock(&m->base, m->framebuffer, 
+                GRALLOC_USAGE_SW_WRITE_RARELY, 
+                0, 0, m->info.xres, m->info.yres,
+                &fb_vaddr);
+
+        m->base.lock(&m->base, buffer, 
+                GRALLOC_USAGE_SW_READ_RARELY, 
+                0, 0, m->info.xres, m->info.yres,
+                &buffer_vaddr);
+
+        memcpy(fb_vaddr, buffer_vaddr, m->finfo.line_length * m->info.yres);
+        
+        m->base.unlock(&m->base, buffer); 
+        m->base.unlock(&m->base, m->framebuffer); 
+    }
+    
+    return 0;
+}
+
+/*****************************************************************************/
+
+int mapFrameBufferLocked(struct private_module_t* module)
+{
+    // already initialized...
+    if (module->framebuffer) {
+        return 0;
+    }
+        
+    char const * const device_template[] = {
+            "/dev/graphics/fb%u",
+            "/dev/fb%u",
+            0 };
+
+    int fd = -1;
+    int i=0;
+    char name[64];
+
+    while ((fd==-1) && device_template[i]) {
+        snprintf(name, 64, device_template[i], 0);
+        fd = open(name, O_RDWR, 0);
+        i++;
+    }
+    if (fd < 0)
+        return -errno;
+
+    struct fb_fix_screeninfo finfo;
+    if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
+        return -errno;
+
+    struct fb_var_screeninfo info;
+    if (ioctl(fd, FBIOGET_VSCREENINFO, &info) == -1)
+        return -errno;
+
+    info.reserved[0] = 0;
+    info.reserved[1] = 0;
+    info.reserved[2] = 0;
+    info.xoffset = 0;
+    info.yoffset = 0;
+    info.activate = FB_ACTIVATE_NOW;
+
+    /*
+     * Explicitly request 5/6/5
+     */
+    info.bits_per_pixel = 16;
+    info.red.offset     = 11;
+    info.red.length     = 5;
+    info.green.offset   = 5;
+    info.green.length   = 6;
+    info.blue.offset    = 0;
+    info.blue.length    = 5;
+    info.transp.offset  = 0;
+    info.transp.length  = 0;
+
+    /*
+     * Request NUM_BUFFERS screens (at lest 2 for page flipping)
+     */
+    info.yres_virtual = info.yres * NUM_BUFFERS;
+
+
+    uint32_t flags = PAGE_FLIP;
+    if (ioctl(fd, FBIOPUT_VSCREENINFO, &info) == -1) {
+        info.yres_virtual = info.yres;
+        flags &= ~PAGE_FLIP;
+        LOGW("FBIOPUT_VSCREENINFO failed, page flipping not supported");
+    }
+
+    if (info.yres_virtual < info.yres * 2) {
+        // we need at least 2 for page-flipping
+        info.yres_virtual = info.yres;
+        flags &= ~PAGE_FLIP;
+        LOGW("page flipping not supported (yres_virtual=%d, requested=%d)",
+                info.yres_virtual, info.yres*2);
+    }
+
+    if (ioctl(fd, FBIOGET_VSCREENINFO, &info) == -1)
+        return -errno;
+
+    int refreshRate = 1000000000000000LLU /
+    (
+            uint64_t( info.upper_margin + info.lower_margin + info.yres )
+            * ( info.left_margin  + info.right_margin + info.xres )
+            * info.pixclock
+    );
+
+    if (refreshRate == 0) {
+        // bleagh, bad info from the driver
+        refreshRate = 60*1000;  // 60 Hz
+    }
+
+    if (int(info.width) <= 0 || int(info.height) <= 0) {
+        // the driver doesn't return that information
+        // default to 160 dpi
+        info.width  = ((info.xres * 25.4f)/160.0f + 0.5f);
+        info.height = ((info.yres * 25.4f)/160.0f + 0.5f);
+    }
+
+    float xdpi = (info.xres * 25.4f) / info.width;
+    float ydpi = (info.yres * 25.4f) / info.height;
+    float fps  = refreshRate / 1000.0f;
+
+    LOGI(   "using (fd=%d)\n"
+            "id           = %s\n"
+            "xres         = %d px\n"
+            "yres         = %d px\n"
+            "xres_virtual = %d px\n"
+            "yres_virtual = %d px\n"
+            "bpp          = %d\n"
+            "r            = %2u:%u\n"
+            "g            = %2u:%u\n"
+            "b            = %2u:%u\n",
+            fd,
+            finfo.id,
+            info.xres,
+            info.yres,
+            info.xres_virtual,
+            info.yres_virtual,
+            info.bits_per_pixel,
+            info.red.offset, info.red.length,
+            info.green.offset, info.green.length,
+            info.blue.offset, info.blue.length
+    );
+
+    LOGI(   "width        = %d mm (%f dpi)\n"
+            "height       = %d mm (%f dpi)\n"
+            "refresh rate = %.2f Hz\n",
+            info.width,  xdpi,
+            info.height, ydpi,
+            fps
+    );
+
+
+    if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
+        return -errno;
+
+    if (finfo.smem_len <= 0)
+        return -errno;
+
+
+    module->flags = flags;
+    module->info = info;
+    module->finfo = finfo;
+    module->xdpi = xdpi;
+    module->ydpi = ydpi;
+    module->fps = fps;
+
+    /*
+     * map the framebuffer
+     */
+
+    int err;
+    size_t fbSize = roundUpToPageSize(finfo.line_length * info.yres_virtual);
+    module->framebuffer = new private_handle_t(dup(fd), fbSize,
+            private_handle_t::PRIV_FLAGS_USES_PMEM);
+
+    module->numBuffers = info.yres_virtual / info.yres;
+    module->bufferMask = 0;
+
+    void* vaddr;
+    gralloc_map(&module->base, module->framebuffer, &vaddr);
+    memset(vaddr, 0, fbSize);
+
+    return 0;
+}
+
+static int mapFrameBuffer(struct private_module_t* module)
+{
+    pthread_mutex_lock(&module->lock);
+    int err = mapFrameBufferLocked(module);
+    pthread_mutex_unlock(&module->lock);
+    return err;
+}
+
+/*****************************************************************************/
+
+static int fb_close(struct hw_device_t *dev)
+{
+    fb_context_t* ctx = (fb_context_t*)dev;
+    if (ctx) {
+        free(ctx);
+    }
+    return 0;
+}
+
+int fb_device_open(hw_module_t const* module, const char* name,
+        hw_device_t** device)
+{
+    int status = -EINVAL;
+    if (!strcmp(name, GRALLOC_HARDWARE_FB0)) {
+
+        alloc_device_t* gralloc_device;
+        status = gralloc_open(module, &gralloc_device);
+        if (status < 0)
+            return status;
+
+        /* initialize our state here */
+        fb_context_t *dev = (fb_context_t*)malloc(sizeof(*dev));
+        memset(dev, 0, sizeof(*dev));
+
+        /* initialize the procs */
+        dev->device.common.tag = HARDWARE_DEVICE_TAG;
+        dev->device.common.version = 0;
+        dev->device.common.module = const_cast<hw_module_t*>(module);
+        dev->device.common.close = fb_close;
+        dev->device.setSwapInterval = fb_setSwapInterval;
+#if SUPPORTS_UPDATE_ON_DEMAND
+        dev->device.setUpdateRect   = fb_setUpdateRect;
+#endif
+        dev->device.post            = fb_post;
+
+        private_module_t* m = (private_module_t*)module;
+        status = mapFrameBuffer(m);
+        if (status >= 0) {
+            int stride = m->finfo.line_length / (m->info.bits_per_pixel >> 3);
+            const_cast<uint32_t&>(dev->device.flags) = 0;
+            const_cast<uint32_t&>(dev->device.width) = m->info.xres;
+            const_cast<uint32_t&>(dev->device.height) = m->info.yres;
+            const_cast<int&>(dev->device.stride) = stride;
+            const_cast<int&>(dev->device.format) = HAL_PIXEL_FORMAT_RGB_565;
+            const_cast<float&>(dev->device.xdpi) = m->xdpi;
+            const_cast<float&>(dev->device.ydpi) = m->ydpi;
+            const_cast<float&>(dev->device.fps) = m->fps;
+            const_cast<int&>(dev->device.minSwapInterval) = 1;
+            const_cast<int&>(dev->device.maxSwapInterval) = 1;
+
+            *device = &dev->device.common;
+        }
+    }
+    return status;
+}
diff --git a/modules/gralloc/gralloc.cpp b/modules/gralloc/gralloc.cpp
new file mode 100644
index 0000000..5a38b33
--- /dev/null
+++ b/modules/gralloc/gralloc.cpp
@@ -0,0 +1,302 @@
+/*
+ * Copyright (C) 2008 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 <limits.h>
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <cutils/ashmem.h>
+#include <cutils/log.h>
+
+#include <hardware/hardware.h>
+#include <hardware/gralloc.h>
+
+#include <fcntl.h>
+#include <errno.h>
+#include <pthread.h>
+
+#include <cutils/log.h>
+#include <cutils/atomic.h>
+
+#include "gralloc_priv.h"
+
+/*****************************************************************************/
+
+struct gralloc_context_t {
+    alloc_device_t  device;
+    /* our private data here */
+};
+
+static int gralloc_alloc_buffer(alloc_device_t* dev,
+        size_t size, int usage, buffer_handle_t* pHandle);
+
+/*****************************************************************************/
+
+int fb_device_open(const hw_module_t* module, const char* name,
+        hw_device_t** device);
+
+static int gralloc_device_open(const hw_module_t* module, const char* name,
+        hw_device_t** device);
+
+extern int gralloc_lock(gralloc_module_t const* module,
+        buffer_handle_t handle, int usage,
+        int l, int t, int w, int h,
+        void** vaddr);
+
+extern int gralloc_unlock(gralloc_module_t const* module, 
+        buffer_handle_t handle);
+
+extern int gralloc_register_buffer(gralloc_module_t const* module,
+        buffer_handle_t handle);
+
+extern int gralloc_unregister_buffer(gralloc_module_t const* module,
+        buffer_handle_t handle);
+
+/*****************************************************************************/
+
+static struct hw_module_methods_t gralloc_module_methods = {
+        open: gralloc_device_open
+};
+
+struct private_module_t HAL_MODULE_INFO_SYM = {
+    base: {
+        common: {
+            tag: HARDWARE_MODULE_TAG,
+            version_major: 1,
+            version_minor: 0,
+            id: GRALLOC_HARDWARE_MODULE_ID,
+            name: "Graphics Memory Allocator Module",
+            author: "The Android Open Source Project",
+            methods: &gralloc_module_methods
+        },
+        registerBuffer: gralloc_register_buffer,
+        unregisterBuffer: gralloc_unregister_buffer,
+        lock: gralloc_lock,
+        unlock: gralloc_unlock,
+    },
+    framebuffer: 0,
+    flags: 0,
+    numBuffers: 0,
+    bufferMask: 0,
+    lock: PTHREAD_MUTEX_INITIALIZER,
+    currentBuffer: 0
+};
+
+/*****************************************************************************/
+
+static int gralloc_alloc_framebuffer_locked(alloc_device_t* dev,
+        size_t size, int usage, buffer_handle_t* pHandle)
+{
+    private_module_t* m = reinterpret_cast<private_module_t*>(
+            dev->common.module);
+
+    // allocate the framebuffer
+    if (m->framebuffer == NULL) {
+        // initialize the framebuffer, the framebuffer is mapped once
+        // and forever.
+        int err = mapFrameBufferLocked(m);
+        if (err < 0) {
+            return err;
+        }
+    }
+
+    const uint32_t bufferMask = m->bufferMask;
+    const uint32_t numBuffers = m->numBuffers;
+    const size_t bufferSize = m->finfo.line_length * m->info.yres;
+    if (numBuffers == 1) {
+        // If we have only one buffer, we never use page-flipping. Instead,
+        // we return a regular buffer which will be memcpy'ed to the main
+        // screen when post is called.
+        int newUsage = (usage & ~GRALLOC_USAGE_HW_FB) | GRALLOC_USAGE_HW_2D;
+        return gralloc_alloc_buffer(dev, bufferSize, newUsage, pHandle);
+    }
+
+    if (bufferMask >= ((1LU<<numBuffers)-1)) {
+        // We ran out of buffers.
+        return -ENOMEM;
+    }
+
+    // create a "fake" handles for it
+    intptr_t vaddr = intptr_t(m->framebuffer->base);
+    private_handle_t* hnd = new private_handle_t(dup(m->framebuffer->fd), size,
+            private_handle_t::PRIV_FLAGS_USES_PMEM |
+            private_handle_t::PRIV_FLAGS_FRAMEBUFFER);
+
+    // find a free slot
+    for (uint32_t i=0 ; i<numBuffers ; i++) {
+        if ((bufferMask & (1LU<<i)) == 0) {
+            m->bufferMask |= (1LU<<i);
+            break;
+        }
+        vaddr += bufferSize;
+    }
+    
+    hnd->base = vaddr;
+    *pHandle = hnd;
+
+    return 0;
+}
+
+static int gralloc_alloc_framebuffer(alloc_device_t* dev,
+        size_t size, int usage, buffer_handle_t* pHandle)
+{
+    private_module_t* m = reinterpret_cast<private_module_t*>(
+            dev->common.module);
+    pthread_mutex_lock(&m->lock);
+    int err = gralloc_alloc_framebuffer_locked(dev, size, usage, pHandle);
+    pthread_mutex_unlock(&m->lock);
+    return err;
+}
+
+
+static int gralloc_alloc_buffer(alloc_device_t* dev,
+        size_t size, int usage, buffer_handle_t* pHandle)
+{
+    size = roundUpToPageSize(size);
+    int flags = 0;
+    if (usage & GRALLOC_USAGE_HW_2D) {
+        flags |= private_handle_t::PRIV_FLAGS_USES_PMEM;
+    }
+    int fd;
+    if ((flags & private_handle_t::PRIV_FLAGS_USES_PMEM) == 0) {
+        fd = ashmem_create_region("Buffer", size);
+    } else {
+        fd = open("/dev/pmem", O_RDWR, 0);
+        // Note: Currently pmem get sized when it is mmaped.
+        // This means that just doing the open doesn't actually allocate
+        // anything. We basically need to do an implicit "mmap"
+        // (under the hood) for pmem regions. However, the current
+        // code will work okay for now thanks to the reference-counting.
+    }
+    if (fd < 0) {
+        return -errno;
+    }
+    private_handle_t* hnd = new private_handle_t(fd, size, flags);
+    *pHandle = hnd;
+    return 0;
+}
+
+/*****************************************************************************/
+
+static int gralloc_alloc(alloc_device_t* dev,
+        int w, int h, int format, int usage,
+        buffer_handle_t* pHandle, int* pStride)
+{
+    if (!pHandle || !pStride)
+        return -EINVAL;
+
+    int align = 4;
+    int bpp = 0;
+    switch (format) {
+        case HAL_PIXEL_FORMAT_RGBA_8888:
+        case HAL_PIXEL_FORMAT_BGRA_8888:
+            bpp = 4;
+            break;
+        case HAL_PIXEL_FORMAT_RGB_565:
+        case HAL_PIXEL_FORMAT_RGBA_5551:
+        case HAL_PIXEL_FORMAT_RGBA_4444:
+            bpp = 2;
+            break;
+        default:
+            return -EINVAL;
+    }
+
+    size_t bpr = (w*bpp + (align-1)) & ~(align-1);
+    size_t size = bpr * h;
+    size_t stride = bpr / bpp;
+
+    int err;
+    if (usage & GRALLOC_USAGE_HW_FB) {
+        err = gralloc_alloc_framebuffer(dev, size, usage, pHandle);
+    } else {
+        err = gralloc_alloc_buffer(dev, size, usage, pHandle);
+    }
+    if (err < 0) {
+        return err;
+    }
+
+    *pStride = stride;
+    return 0;
+}
+
+static int gralloc_free(alloc_device_t* dev,
+        buffer_handle_t handle)
+{
+    if (private_handle_t::validate(handle) < 0)
+        return -EINVAL;
+
+    private_handle_t const* hnd = reinterpret_cast<private_handle_t const*>(handle);
+    if (hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER) {
+        // free this buffer
+        private_module_t* m = reinterpret_cast<private_module_t*>(
+                dev->common.module);
+        const size_t bufferSize = m->finfo.line_length * m->info.yres;
+        int index = (hnd->base - m->framebuffer->base) / bufferSize;
+        m->bufferMask &= ~(1<<index); 
+    }
+
+    gralloc_module_t* m = reinterpret_cast<gralloc_module_t*>(
+            dev->common.module);
+    gralloc_unregister_buffer(m, handle);
+    
+    close(hnd->fd);
+    delete hnd;
+    return 0;
+}
+
+/*****************************************************************************/
+
+static int gralloc_close(struct hw_device_t *dev)
+{
+    gralloc_context_t* ctx = reinterpret_cast<gralloc_context_t*>(dev);
+    if (ctx) {
+        /* TODO: keep a list of all buffer_handle_t created, and free them
+         * all here.
+         */
+        free(ctx);
+    }
+    return 0;
+}
+
+int gralloc_device_open(const hw_module_t* module, const char* name,
+        hw_device_t** device)
+{
+    int status = -EINVAL;
+    if (!strcmp(name, GRALLOC_HARDWARE_GPU0)) {
+        gralloc_context_t *dev;
+        dev = (gralloc_context_t*)malloc(sizeof(*dev));
+
+        /* initialize our state here */
+        memset(dev, 0, sizeof(*dev));
+
+        /* initialize the procs */
+        dev->device.common.tag = HARDWARE_DEVICE_TAG;
+        dev->device.common.version = 0;
+        dev->device.common.module = const_cast<hw_module_t*>(module);
+        dev->device.common.close = gralloc_close;
+
+        dev->device.alloc   = gralloc_alloc;
+        dev->device.free    = gralloc_free;
+
+        *device = &dev->device.common;
+        status = 0;
+    } else {
+        status = fb_device_open(module, name, device);
+    }
+    return status;
+}
diff --git a/modules/gralloc/gralloc_priv.h b/modules/gralloc/gralloc_priv.h
new file mode 100644
index 0000000..117999d
--- /dev/null
+++ b/modules/gralloc/gralloc_priv.h
@@ -0,0 +1,223 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+#ifndef GRALLOC_PRIV_H_
+#define GRALLOC_PRIV_H_
+
+#include <stdint.h>
+#include <asm/page.h>
+#include <limits.h>
+#include <sys/cdefs.h>
+#include <hardware/gralloc.h>
+#include <pthread.h>
+
+#include <cutils/native_handle.h>
+
+#if HAVE_ANDROID_OS
+#include <linux/fb.h>
+#endif
+
+/*****************************************************************************/
+
+inline size_t roundUpToPageSize(size_t x) {
+    return (x + (PAGESIZE-1)) & ~(PAGESIZE-1);
+}
+
+int gralloc_map(gralloc_module_t const* module,
+        buffer_handle_t handle, void** vaddr);
+
+int gralloc_unmap(gralloc_module_t const* module, 
+        buffer_handle_t handle);
+
+
+int mapFrameBufferLocked(struct private_module_t* module);
+
+/*****************************************************************************/
+
+struct private_handle_t;
+
+struct private_module_t {
+    gralloc_module_t base;
+
+    private_handle_t* framebuffer;
+    uint32_t flags;
+    uint32_t numBuffers;
+    uint32_t bufferMask;
+    pthread_mutex_t lock;
+    buffer_handle_t currentBuffer;
+    struct fb_var_screeninfo info;
+    struct fb_fix_screeninfo finfo;
+    float xdpi;
+    float ydpi;
+    float fps;
+    
+    enum {
+        // flag to indicate we'll post this buffer
+        PRIV_USAGE_LOCKED_FOR_POST = 0x80000000
+    };
+};
+
+/*****************************************************************************/
+
+struct private_handle_t : public native_handle
+{
+    enum {
+        PRIV_FLAGS_FRAMEBUFFER = 0x00000001,
+        PRIV_FLAGS_USES_PMEM   = 0x00000002,
+        PRIV_FLAGS_MAPPED      = 0x00000004,    // FIXME: should be out-of-line
+    };
+
+    int     fd;
+    int     magic;
+    int     flags;
+    int     size;
+    // FIXME: the attributes below should be out-of-line
+    int     base;
+    int     lockState;
+    int     writeOwner;
+
+    static const int sNumInts = 6;
+    static const int sNumFds = 1;
+    static const int sMagic = 0x3141592;
+
+    private_handle_t(int fd, int size, int flags) :
+        fd(fd), magic(sMagic), flags(flags), size(size), base(0),
+        lockState(0), writeOwner(0) 
+    {
+        version = sizeof(native_handle);
+        numInts = sNumInts;
+        numFds = sNumFds;
+    }
+
+    ~private_handle_t() {
+        magic = 0;
+    }
+
+    bool usesPhysicallyContiguousMemory() {
+        return (flags & PRIV_FLAGS_USES_PMEM) != 0;
+    }
+
+    static int validate(const native_handle* h) {
+        if (!h || h->version != sizeof(native_handle) ||
+                h->numInts!=sNumInts || h->numFds!=sNumFds) {
+            return -EINVAL;
+        }
+        const private_handle_t* hnd = (const private_handle_t*)h;
+        if (hnd->magic != sMagic)
+            return -EINVAL;
+        return 0;
+    }
+
+    static private_handle_t* dynamicCast(const native_handle* in) {
+        if (validate(in) == 0) {
+            return (private_handle_t*) in;
+        }
+        return NULL;
+    }
+};
+
+/*****************************************************************************/
+
+template<typename T>
+struct growable_sorted_array_t {
+    int size;
+    int count;
+    T* data;
+
+    growable_sorted_array_t() : size(0), count(0), data(0) {
+    }
+
+    growable_sorted_array_t(int initialSize)
+        : size(initialSize), count(0), data(0)
+    {
+        data = new T[initialSize];
+    }
+
+    ~growable_sorted_array_t() {
+        delete[] data;
+    }
+
+    /** Returns true if we found an exact match.
+     * Argument index is set to the the first index >= key in place.
+     * Index will be in range 0..count inclusive.
+     *
+     */
+    bool find(const T& key, int& index) {
+        return binarySearch(0, count-1, key, index);
+    }
+
+    T* at(int index){
+        if (index >= 0  && index < count) {
+            return data + index;
+        }
+        return 0;
+    }
+
+    void insert(int index, const T& item) {
+        if (index >= 0 && index <= count) {
+            if (count + 1 > size) {
+                int newSize = size * 2;
+                if (newSize < count + 1) {
+                    newSize = count + 1;
+                }
+                T* newData = new T[newSize];
+                if (size > 0) {
+                    memcpy(newData, data, sizeof(T) * count);
+                }
+                data = newData;
+                size = newSize;
+            }
+            int toMove = count - index;
+            if (toMove > 0) {
+                memmove(data + index + 1, data + index, sizeof(T) * toMove);
+            }
+            count++;
+            data[index] = item;
+        }
+    }
+
+    void remove(int index) {
+        if (index >= 0 && index < count) {
+            int toMove = (count - 1) - index;
+            if (toMove > 0) {
+                memmove(data + index, data + index + 1, sizeof(T) * toMove);
+            }
+            count--;
+        }
+    }
+
+    /** Return the first index >= key. May be in range first..last+1. */
+    int binarySearch(int first, int last, const T& key, int& index)
+    {
+        while (first <= last) {
+            int mid = (first + last) / 2;
+            int cmp = compare(key, data[mid]);
+            if (cmp > 0) {
+                first = mid + 1;
+            } else if (cmp < 0) {
+                last = mid - 1;
+            } else {
+                index = mid;
+                return true;
+            }
+        }
+        index = first;
+        return false;
+    }
+};
+
+
+#endif /* GRALLOC_PRIV_H_ */
diff --git a/modules/gralloc/mapper.cpp b/modules/gralloc/mapper.cpp
new file mode 100644
index 0000000..bbcffac
--- /dev/null
+++ b/modules/gralloc/mapper.cpp
@@ -0,0 +1,361 @@
+/*
+ * Copyright (C) 2008 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 <limits.h>
+#include <errno.h>
+#include <pthread.h>
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <cutils/log.h>
+#include <cutils/atomic.h>
+
+#include <hardware/hardware.h>
+#include <hardware/gralloc.h>
+
+#include "gralloc_priv.h"
+
+/*****************************************************************************/
+
+struct mapped_buffer_t {
+    intptr_t key;
+    int size;
+    int base;
+    int refCount;
+
+    mapped_buffer_t() { /* no init */ };
+    mapped_buffer_t(private_handle_t* hnd) 
+        : key(intptr_t(hnd)), size(hnd->size), base(0), refCount(0) {
+    }
+};
+
+static int compare(const mapped_buffer_t& a, const mapped_buffer_t& b) {
+    if (a.key < b.key) {
+        return -1;
+    }
+    if (a.key > b.key) {
+        return 1;
+    }
+    return 0;
+}
+
+struct mapped_buffers_t {
+    pthread_mutex_t mutex;
+    growable_sorted_array_t<mapped_buffer_t> records;
+
+    int map(gralloc_module_t const* module,
+            buffer_handle_t handle,
+            void** vaddr)
+    {
+        private_handle_t* hnd = (private_handle_t*)(handle);
+        mapped_buffer_t key(hnd);
+        //printRecord(ANDROID_LOG_DEBUG, "map", &key);
+        int result = 0;
+        mapped_buffer_t* record = 0;
+        pthread_mutex_lock(&mutex);
+        // From here to the end of the function we return by jumping to "exit"
+        // so that we always unlock the mutex.
+
+        int index = -1;
+        if (!records.find(key, index)) {
+            //LOGD("New item at %d", index);
+            void* mappedAddress = mmap(0, hnd->size,
+                    PROT_READ|PROT_WRITE, MAP_SHARED, hnd->fd, 0);
+            if (mappedAddress == MAP_FAILED) {
+                result = -errno;
+                //LOGE("map failed %d", result);
+                goto exit;
+            }
+            key.base = intptr_t(mappedAddress);
+            records.insert(index, key);
+            record = records.at(index);
+        } else {
+            //LOGD("Found existing mapping at index %d", index);
+            record = records.at(index);
+            if (record->size != key.size) {
+                LOGE("Requested a new mapping at the same offset"
+                     "but with a different size");
+                printRecord(ANDROID_LOG_ERROR, "old", record);
+                printRecord(ANDROID_LOG_ERROR, "new", &key);
+                result = -EINVAL;
+                goto exit;
+            }
+        }
+        record->refCount += 1;
+        hnd->base = record->base;
+        *vaddr = (void*) record->base;
+    exit:
+        //print();
+        pthread_mutex_unlock(&mutex);
+        return result;
+    }
+
+    int unmap(gralloc_module_t const* module,
+            buffer_handle_t handle)
+    {
+        mapped_buffer_t key((private_handle_t*) handle);
+        //printRecord(ANDROID_LOG_DEBUG, "unmap", &key);
+        int index = -1;
+        int result = 0;
+        mapped_buffer_t* record = 0;
+        pthread_mutex_lock(&mutex);
+        // From here to the end of the function we return by jumping to "exit"
+        // so that we always unlock the mutex.
+
+        if (!records.find(key, index)) {
+            // This handle is not currently locked.
+            //LOGE("Could not find existing mapping near %d", index);
+            result = -ENOENT;
+            goto exit;
+        }
+        record = records.at(index);
+        //printRecord(ANDROID_LOG_DEBUG, "record", record);
+        record->refCount -= 1;
+        if (record->refCount == 0) {
+            //LOGD("Unmapping...");
+            if (munmap((void*)record->base, record->size) < 0) {
+                result = -errno;
+                //LOGE("Could not unmap %d", result);
+            }
+            records.remove(index);
+            ((private_handle_t*)handle)->base = 0;
+        }
+
+    exit:
+        //print();
+        pthread_mutex_unlock(&mutex);
+        return result;
+    }
+
+    void print() {
+        char prefix[16];
+        LOGD("Dumping records: count=%d size=%d", records.count, records.size);
+        for(int i=0; i<records.count ; i++) {
+            sprintf(prefix, "%3d", i);
+            printRecord(ANDROID_LOG_DEBUG, prefix, records.at(i));
+        }
+    }
+
+    void printRecord(int level, const char* what, mapped_buffer_t* record) {
+        LOG_PRI(level, LOG_TAG,
+          "%s: key=0x%08x, size=0x%08x, base=0x%08x refCount=%d",
+           what, int(record->key), record->size, 
+           record->base, record->refCount);
+    }
+};
+
+static mapped_buffers_t sMappedBuffers  = {
+    mutex: PTHREAD_MUTEX_INITIALIZER
+};
+
+/*****************************************************************************/
+
+int gralloc_map(gralloc_module_t const* module,
+        buffer_handle_t handle,
+        void** vaddr)
+{
+    if (private_handle_t::validate(handle) < 0)
+        return -EINVAL;
+
+    private_handle_t* hnd = (private_handle_t*)(handle);
+    if (hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER) {
+        const private_module_t* m = 
+            reinterpret_cast<const private_module_t*>(module);
+        handle = m->framebuffer;
+    }
+    
+    int err = sMappedBuffers.map(module, handle, vaddr);
+    
+    if (hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER) {
+        *vaddr = (void*)hnd->base;
+    }
+    
+    return err;
+}
+
+int gralloc_unmap(gralloc_module_t const* module,
+        buffer_handle_t handle)
+{
+    if (private_handle_t::validate(handle) < 0)
+        return -EINVAL;
+
+    private_handle_t* hnd = (private_handle_t*)(handle);
+    if (hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER) {
+        const private_module_t* m = 
+            reinterpret_cast<const private_module_t*>(module);
+        handle = m->framebuffer;
+    }
+
+    return sMappedBuffers.unmap(module, handle);
+}
+
+int gralloc_register_buffer(gralloc_module_t const* module,
+        buffer_handle_t handle)
+{
+    if (private_handle_t::validate(handle) < 0)
+        return -EINVAL;
+    
+    // In this implementation, we don't need to do anything here
+
+    /* FIXME: we need to initialize the buffer as not mapped/not locked
+     * because it shouldn't when this function is called the first time
+     * in a new process. ideally these flags shouldn't be part of the
+     * handle, but instead maintained in the kernel or at least 
+     * out-of-line
+     */ 
+    private_handle_t* hnd = (private_handle_t*)(handle);
+    hnd->base = 0;
+    hnd->flags &= ~private_handle_t::PRIV_FLAGS_MAPPED;
+    hnd->lockState = 0;
+    hnd->writeOwner = 0;
+    
+    return 0;
+}
+
+int gralloc_unregister_buffer(gralloc_module_t const* module,
+        buffer_handle_t handle)
+{
+    if (private_handle_t::validate(handle) < 0)
+        return -EINVAL;
+
+    /*
+     * If the buffer has been mapped during a lock operation, it's time
+     * to unmap it. It's an error to be here with a locked buffer.
+     * NOTE: the framebuffer is handled differently and is never unmapped.
+     */
+
+    private_handle_t* hnd = (private_handle_t*)(handle);
+    
+    LOGE_IF(hnd->lockState, "handle %p still locked (state=%08x)",
+            hnd, hnd->lockState);
+
+    if (hnd->flags & private_handle_t::PRIV_FLAGS_MAPPED) {
+        if (!(hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER)) {
+            gralloc_unmap(module, handle);
+            LOGE_IF(hnd->base,
+                    "handle %p still mapped at %p",
+                    hnd, (void*)hnd->base);
+        }
+    }
+    
+    return 0;
+}
+
+int gralloc_lock(gralloc_module_t const* module,
+        buffer_handle_t handle, int usage,
+        int l, int t, int w, int h,
+        void** vaddr)
+{
+    if (private_handle_t::validate(handle) < 0)
+        return -EINVAL;
+
+    int err = 0;
+    private_handle_t* hnd = (private_handle_t*)(handle);
+    int32_t current_value, new_value;
+    int retry;
+
+    do {
+        current_value = hnd->lockState;
+        new_value = current_value;
+        
+        if (current_value>>31) {
+            // already locked for write 
+            LOGE("handle %p already locked for write", handle);
+            return -EBUSY;
+        } else if (current_value<<1) {
+            // already locked for read
+            if (usage & (GRALLOC_USAGE_SW_WRITE_MASK | GRALLOC_USAGE_HW_RENDER)) {
+                LOGE("handle %p already locked for read", handle);
+                return -EBUSY;
+            } else {
+                // this is not an error, but for now we want to know
+                LOGD("%p already locked for read... count = %d", 
+                        handle, (current_value & ~(1<<31)));
+            }
+        }
+
+        // not currently locked
+        if (usage & (GRALLOC_USAGE_SW_WRITE_MASK | GRALLOC_USAGE_HW_RENDER)) {
+            // locking for write
+            new_value |= (1<<31);
+        }
+        new_value++;
+
+        retry = android_atomic_cmpxchg(current_value, new_value, 
+                (volatile int32_t*)&hnd->lockState);
+    } while (retry);
+    
+    if (new_value>>31) {
+        // locking for write, store the tid
+        hnd->writeOwner = gettid();
+    }
+
+    if (usage & (GRALLOC_USAGE_SW_READ_MASK | GRALLOC_USAGE_SW_WRITE_MASK)) {
+        if (hnd->flags & private_handle_t::PRIV_FLAGS_MAPPED) {
+            *vaddr = (void*)hnd->base;
+        } else {
+            hnd->flags |= private_handle_t::PRIV_FLAGS_MAPPED;
+            err = gralloc_map(module, handle, vaddr);
+        }
+    }
+
+    return err;
+}
+
+int gralloc_unlock(gralloc_module_t const* module, 
+        buffer_handle_t handle)
+{
+    if (private_handle_t::validate(handle) < 0)
+        return -EINVAL;
+
+    private_handle_t* hnd = (private_handle_t*)(handle);
+    int32_t current_value, new_value;
+
+    do {
+        current_value = hnd->lockState;
+        new_value = current_value;
+
+        if (current_value>>31) {
+            // locked for write
+            if (hnd->writeOwner == gettid()) {
+                hnd->writeOwner = 0;
+                new_value &= ~(1<<31);
+            }
+        }
+
+        if ((new_value<<1) == 0) {
+            LOGE("handle %p not locked", handle);
+            return -EINVAL;
+        }
+
+        new_value--;
+
+    } while (android_atomic_cmpxchg(current_value, new_value, 
+            (volatile int32_t*)&hnd->lockState));
+
+
+    /* FOR DEBUGGING
+    if (hnd->flags & private_handle_t::PRIV_FLAGS_MAPPED) {
+        if (gralloc_unmap(module, handle) == 0) {
+            hnd->flags &= ~private_handle_t::PRIV_FLAGS_MAPPED;
+        }
+    }
+     */
+
+    return 0;
+}
diff --git a/modules/overlay/overlay.cpp b/modules/overlay/overlay.cpp
index 0246b5b..a91df58 100644
--- a/modules/overlay/overlay.cpp
+++ b/modules/overlay/overlay.cpp
@@ -44,7 +44,7 @@
     open: overlay_device_open
 };
 
-const struct overlay_module_t HAL_MODULE_INFO_SYM = {
+struct overlay_module_t HAL_MODULE_INFO_SYM = {
     common: {
         tag: HARDWARE_MODULE_TAG,
         version_major: 1,