--- /dev/null
+/*
+ * Copyright (c) 2012, Microsoft Corporation.
+ *
+ * Author:
+ *   Haiyang Zhang <haiyangz@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ */
+
+/*
+ * Hyper-V Synthetic Video Frame Buffer Driver
+ *
+ * This is the driver for the Hyper-V Synthetic Video, which supports
+ * screen resolution up to Full HD 1920x1080 with 32 bit color on Windows
+ * Server 2012, and 1600x1200 with 16 bit color on Windows Server 2008 R2
+ * or earlier.
+ *
+ * It also solves the double mouse cursor issue of the emulated video mode.
+ *
+ * The default screen resolution is 1152x864, which may be changed by a
+ * kernel parameter:
+ *     video=hyperv_fb:<width>x<height>
+ *     For example: video=hyperv_fb:1280x1024
+ *
+ * Portrait orientation is also supported:
+ *     For example: video=hyperv_fb:864x1152
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/fb.h>
+#include <linux/pci.h>
+
+#include <linux/hyperv.h>
+
+
+/* Hyper-V Synthetic Video Protocol definitions and structures */
+#define MAX_VMBUS_PKT_SIZE 0x4000
+
+#define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
+#define SYNTHVID_VERSION_WIN7 SYNTHVID_VERSION(3, 0)
+#define SYNTHVID_VERSION_WIN8 SYNTHVID_VERSION(3, 2)
+
+#define SYNTHVID_DEPTH_WIN7 16
+#define SYNTHVID_DEPTH_WIN8 32
+
+#define SYNTHVID_FB_SIZE_WIN7 (4 * 1024 * 1024)
+#define SYNTHVID_WIDTH_MAX_WIN7 1600
+#define SYNTHVID_HEIGHT_MAX_WIN7 1200
+
+#define SYNTHVID_FB_SIZE_WIN8 (8 * 1024 * 1024)
+
+#define PCI_VENDOR_ID_MICROSOFT 0x1414
+#define PCI_DEVICE_ID_HYPERV_VIDEO 0x5353
+
+
+enum pipe_msg_type {
+       PIPE_MSG_INVALID,
+       PIPE_MSG_DATA,
+       PIPE_MSG_MAX
+};
+
+struct pipe_msg_hdr {
+       u32 type;
+       u32 size; /* size of message after this field */
+} __packed;
+
+
+enum synthvid_msg_type {
+       SYNTHVID_ERROR                  = 0,
+       SYNTHVID_VERSION_REQUEST        = 1,
+       SYNTHVID_VERSION_RESPONSE       = 2,
+       SYNTHVID_VRAM_LOCATION          = 3,
+       SYNTHVID_VRAM_LOCATION_ACK      = 4,
+       SYNTHVID_SITUATION_UPDATE       = 5,
+       SYNTHVID_SITUATION_UPDATE_ACK   = 6,
+       SYNTHVID_POINTER_POSITION       = 7,
+       SYNTHVID_POINTER_SHAPE          = 8,
+       SYNTHVID_FEATURE_CHANGE         = 9,
+       SYNTHVID_DIRT                   = 10,
+
+       SYNTHVID_MAX                    = 11
+};
+
+struct synthvid_msg_hdr {
+       u32 type;
+       u32 size;  /* size of this header + payload after this field*/
+} __packed;
+
+
+struct synthvid_version_req {
+       u32 version;
+} __packed;
+
+struct synthvid_version_resp {
+       u32 version;
+       u8 is_accepted;
+       u8 max_video_outputs;
+} __packed;
+
+struct synthvid_vram_location {
+       u64 user_ctx;
+       u8 is_vram_gpa_specified;
+       u64 vram_gpa;
+} __packed;
+
+struct synthvid_vram_location_ack {
+       u64 user_ctx;
+} __packed;
+
+struct video_output_situation {
+       u8 active;
+       u32 vram_offset;
+       u8 depth_bits;
+       u32 width_pixels;
+       u32 height_pixels;
+       u32 pitch_bytes;
+} __packed;
+
+struct synthvid_situation_update {
+       u64 user_ctx;
+       u8 video_output_count;
+       struct video_output_situation video_output[1];
+} __packed;
+
+struct synthvid_situation_update_ack {
+       u64 user_ctx;
+} __packed;
+
+struct synthvid_pointer_position {
+       u8 is_visible;
+       u8 video_output;
+       s32 image_x;
+       s32 image_y;
+} __packed;
+
+
+#define CURSOR_MAX_X 96
+#define CURSOR_MAX_Y 96
+#define CURSOR_ARGB_PIXEL_SIZE 4
+#define CURSOR_MAX_SIZE (CURSOR_MAX_X * CURSOR_MAX_Y * CURSOR_ARGB_PIXEL_SIZE)
+#define CURSOR_COMPLETE (-1)
+
+struct synthvid_pointer_shape {
+       u8 part_idx;
+       u8 is_argb;
+       u32 width; /* CURSOR_MAX_X at most */
+       u32 height; /* CURSOR_MAX_Y at most */
+       u32 hot_x; /* hotspot relative to upper-left of pointer image */
+       u32 hot_y;
+       u8 data[4];
+} __packed;
+
+struct synthvid_feature_change {
+       u8 is_dirt_needed;
+       u8 is_ptr_pos_needed;
+       u8 is_ptr_shape_needed;
+       u8 is_situ_needed;
+} __packed;
+
+struct rect {
+       s32 x1, y1; /* top left corner */
+       s32 x2, y2; /* bottom right corner, exclusive */
+} __packed;
+
+struct synthvid_dirt {
+       u8 video_output;
+       u8 dirt_count;
+       struct rect rect[1];
+} __packed;
+
+struct synthvid_msg {
+       struct pipe_msg_hdr pipe_hdr;
+       struct synthvid_msg_hdr vid_hdr;
+       union {
+               struct synthvid_version_req ver_req;
+               struct synthvid_version_resp ver_resp;
+               struct synthvid_vram_location vram;
+               struct synthvid_vram_location_ack vram_ack;
+               struct synthvid_situation_update situ;
+               struct synthvid_situation_update_ack situ_ack;
+               struct synthvid_pointer_position ptr_pos;
+               struct synthvid_pointer_shape ptr_shape;
+               struct synthvid_feature_change feature_chg;
+               struct synthvid_dirt dirt;
+       };
+} __packed;
+
+
+
+/* FB driver definitions and structures */
+#define HVFB_WIDTH 1152 /* default screen width */
+#define HVFB_HEIGHT 864 /* default screen height */
+#define HVFB_WIDTH_MIN 640
+#define HVFB_HEIGHT_MIN 480
+
+#define RING_BUFSIZE (256 * 1024)
+#define VSP_TIMEOUT (10 * HZ)
+#define HVFB_UPDATE_DELAY (HZ / 20)
+
+struct hvfb_par {
+       struct fb_info *info;
+       bool fb_ready; /* fb device is ready */
+       struct completion wait;
+       u32 synthvid_version;
+
+       struct delayed_work dwork;
+       bool update;
+
+       u32 pseudo_palette[16];
+       u8 init_buf[MAX_VMBUS_PKT_SIZE];
+       u8 recv_buf[MAX_VMBUS_PKT_SIZE];
+};
+
+static uint screen_width = HVFB_WIDTH;
+static uint screen_height = HVFB_HEIGHT;
+static uint screen_depth;
+static uint screen_fb_size;
+
+/* Send message to Hyper-V host */
+static inline int synthvid_send(struct hv_device *hdev,
+                               struct synthvid_msg *msg)
+{
+       static atomic64_t request_id = ATOMIC64_INIT(0);
+       int ret;
+
+       msg->pipe_hdr.type = PIPE_MSG_DATA;
+       msg->pipe_hdr.size = msg->vid_hdr.size;
+
+       ret = vmbus_sendpacket(hdev->channel, msg,
+                              msg->vid_hdr.size + sizeof(struct pipe_msg_hdr),
+                              atomic64_inc_return(&request_id),
+                              VM_PKT_DATA_INBAND, 0);
+
+       if (ret)
+               pr_err("Unable to send packet via vmbus\n");
+
+       return ret;
+}
+
+
+/* Send screen resolution info to host */
+static int synthvid_send_situ(struct hv_device *hdev)
+{
+       struct fb_info *info = hv_get_drvdata(hdev);
+       struct synthvid_msg msg;
+
+       if (!info)
+               return -ENODEV;
+
+       memset(&msg, 0, sizeof(struct synthvid_msg));
+
+       msg.vid_hdr.type = SYNTHVID_SITUATION_UPDATE;
+       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+               sizeof(struct synthvid_situation_update);
+       msg.situ.user_ctx = 0;
+       msg.situ.video_output_count = 1;
+       msg.situ.video_output[0].active = 1;
+       msg.situ.video_output[0].vram_offset = 0;
+       msg.situ.video_output[0].depth_bits = info->var.bits_per_pixel;
+       msg.situ.video_output[0].width_pixels = info->var.xres;
+       msg.situ.video_output[0].height_pixels = info->var.yres;
+       msg.situ.video_output[0].pitch_bytes = info->fix.line_length;
+
+       synthvid_send(hdev, &msg);
+
+       return 0;
+}
+
+/* Send mouse pointer info to host */
+static int synthvid_send_ptr(struct hv_device *hdev)
+{
+       struct synthvid_msg msg;
+
+       memset(&msg, 0, sizeof(struct synthvid_msg));
+       msg.vid_hdr.type = SYNTHVID_POINTER_POSITION;
+       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+               sizeof(struct synthvid_pointer_position);
+       msg.ptr_pos.is_visible = 1;
+       msg.ptr_pos.video_output = 0;
+       msg.ptr_pos.image_x = 0;
+       msg.ptr_pos.image_y = 0;
+       synthvid_send(hdev, &msg);
+
+       memset(&msg, 0, sizeof(struct synthvid_msg));
+       msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
+       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+               sizeof(struct synthvid_pointer_shape);
+       msg.ptr_shape.part_idx = CURSOR_COMPLETE;
+       msg.ptr_shape.is_argb = 1;
+       msg.ptr_shape.width = 1;
+       msg.ptr_shape.height = 1;
+       msg.ptr_shape.hot_x = 0;
+       msg.ptr_shape.hot_y = 0;
+       msg.ptr_shape.data[0] = 0;
+       msg.ptr_shape.data[1] = 1;
+       msg.ptr_shape.data[2] = 1;
+       msg.ptr_shape.data[3] = 1;
+       synthvid_send(hdev, &msg);
+
+       return 0;
+}
+
+/* Send updated screen area (dirty rectangle) location to host */
+static int synthvid_update(struct fb_info *info)
+{
+       struct hv_device *hdev = device_to_hv_device(info->device);
+       struct synthvid_msg msg;
+
+       memset(&msg, 0, sizeof(struct synthvid_msg));
+
+       msg.vid_hdr.type = SYNTHVID_DIRT;
+       msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+               sizeof(struct synthvid_dirt);
+       msg.dirt.video_output = 0;
+       msg.dirt.dirt_count = 1;
+       msg.dirt.rect[0].x1 = 0;
+       msg.dirt.rect[0].y1 = 0;
+       msg.dirt.rect[0].x2 = info->var.xres;
+       msg.dirt.rect[0].y2 = info->var.yres;
+
+       synthvid_send(hdev, &msg);
+
+       return 0;
+}
+
+
+/*
+ * Actions on received messages from host:
+ * Complete the wait event.
+ * Or, reply with screen and cursor info.
+ */
+static void synthvid_recv_sub(struct hv_device *hdev)
+{
+       struct fb_info *info = hv_get_drvdata(hdev);
+       struct hvfb_par *par;
+       struct synthvid_msg *msg;
+
+       if (!info)
+               return;
+
+       par = info->par;
+       msg = (struct synthvid_msg *)par->recv_buf;
+
+       /* Complete the wait event */
+       if (msg->vid_hdr.type == SYNTHVID_VERSION_RESPONSE ||
+           msg->vid_hdr.type == SYNTHVID_VRAM_LOCATION_ACK) {
+               memcpy(par->init_buf, msg, MAX_VMBUS_PKT_SIZE);
+               complete(&par->wait);
+               return;
+       }
+
+       /* Reply with screen and cursor info */
+       if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE) {
+               if (par->fb_ready) {
+                       synthvid_send_ptr(hdev);
+                       synthvid_send_situ(hdev);
+               }
+
+               par->update = msg->feature_chg.is_dirt_needed;
+               if (par->update)
+                       schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
+       }
+}
+
+/* Receive callback for messages from the host */
+static void synthvid_receive(void *ctx)
+{
+       struct hv_device *hdev = ctx;
+       struct fb_info *info = hv_get_drvdata(hdev);
+       struct hvfb_par *par;
+       struct synthvid_msg *recv_buf;
+       u32 bytes_recvd;
+       u64 req_id;
+       int ret;
+
+       if (!info)
+               return;
+
+       par = info->par;
+       recv_buf = (struct synthvid_msg *)par->recv_buf;
+
+       do {
+               ret = vmbus_recvpacket(hdev->channel, recv_buf,
+                                      MAX_VMBUS_PKT_SIZE,
+                                      &bytes_recvd, &req_id);
+               if (bytes_recvd > 0 &&
+                   recv_buf->pipe_hdr.type == PIPE_MSG_DATA)
+                       synthvid_recv_sub(hdev);
+       } while (bytes_recvd > 0 && ret == 0);
+}
+
+/* Check synthetic video protocol version with the host */
+static int synthvid_negotiate_ver(struct hv_device *hdev, u32 ver)
+{
+       struct fb_info *info = hv_get_drvdata(hdev);
+       struct hvfb_par *par = info->par;
+       struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
+       int t, ret = 0;
+
+       memset(msg, 0, sizeof(struct synthvid_msg));
+       msg->vid_hdr.type = SYNTHVID_VERSION_REQUEST;
+       msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+               sizeof(struct synthvid_version_req);
+       msg->ver_req.version = ver;
+       synthvid_send(hdev, msg);
+
+       t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
+       if (!t) {
+               pr_err("Time out on waiting version response\n");
+               ret = -ETIMEDOUT;
+               goto out;
+       }
+       if (!msg->ver_resp.is_accepted) {
+               ret = -ENODEV;
+               goto out;
+       }
+
+       par->synthvid_version = ver;
+
+out:
+       return ret;
+}
+
+/* Connect to VSP (Virtual Service Provider) on host */
+static int synthvid_connect_vsp(struct hv_device *hdev)
+{
+       struct fb_info *info = hv_get_drvdata(hdev);
+       struct hvfb_par *par = info->par;
+       int ret;
+
+       ret = vmbus_open(hdev->channel, RING_BUFSIZE, RING_BUFSIZE,
+                        NULL, 0, synthvid_receive, hdev);
+       if (ret) {
+               pr_err("Unable to open vmbus channel\n");
+               return ret;
+       }
+
+       /* Negotiate the protocol version with host */
+       if (vmbus_proto_version == VERSION_WS2008 ||
+           vmbus_proto_version == VERSION_WIN7)
+               ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN7);
+       else
+               ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN8);
+
+       if (ret) {
+               pr_err("Synthetic video device version not accepted\n");
+               goto error;
+       }
+
+       if (par->synthvid_version == SYNTHVID_VERSION_WIN7) {
+               screen_depth = SYNTHVID_DEPTH_WIN7;
+               screen_fb_size = SYNTHVID_FB_SIZE_WIN7;
+       } else {
+               screen_depth = SYNTHVID_DEPTH_WIN8;
+               screen_fb_size = SYNTHVID_FB_SIZE_WIN8;
+       }
+
+       return 0;
+
+error:
+       vmbus_close(hdev->channel);
+       return ret;
+}
+
+/* Send VRAM and Situation messages to the host */
+static int synthvid_send_config(struct hv_device *hdev)
+{
+       struct fb_info *info = hv_get_drvdata(hdev);
+       struct hvfb_par *par = info->par;
+       struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
+       int t, ret = 0;
+
+       /* Send VRAM location */
+       memset(msg, 0, sizeof(struct synthvid_msg));
+       msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION;
+       msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+               sizeof(struct synthvid_vram_location);
+       msg->vram.user_ctx = msg->vram.vram_gpa = info->fix.smem_start;
+       msg->vram.is_vram_gpa_specified = 1;
+       synthvid_send(hdev, msg);
+
+       t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
+       if (!t) {
+               pr_err("Time out on waiting vram location ack\n");
+               ret = -ETIMEDOUT;
+               goto out;
+       }
+       if (msg->vram_ack.user_ctx != info->fix.smem_start) {
+               pr_err("Unable to set VRAM location\n");
+               ret = -ENODEV;
+               goto out;
+       }
+
+       /* Send pointer and situation update */
+       synthvid_send_ptr(hdev);
+       synthvid_send_situ(hdev);
+
+out:
+       return ret;
+}
+
+
+/*
+ * Delayed work callback:
+ * It is called at HVFB_UPDATE_DELAY or longer time interval to process
+ * screen updates. It is re-scheduled if further update is necessary.
+ */
+static void hvfb_update_work(struct work_struct *w)
+{
+       struct hvfb_par *par = container_of(w, struct hvfb_par, dwork.work);
+       struct fb_info *info = par->info;
+
+       if (par->fb_ready)
+               synthvid_update(info);
+
+       if (par->update)
+               schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
+}
+
+
+/* Framebuffer operation handlers */
+
+static int hvfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+       if (var->xres < HVFB_WIDTH_MIN || var->yres < HVFB_HEIGHT_MIN ||
+           var->xres > screen_width || var->yres >  screen_height ||
+           var->bits_per_pixel != screen_depth)
+               return -EINVAL;
+
+       var->xres_virtual = var->xres;
+       var->yres_virtual = var->yres;
+
+       return 0;
+}
+
+static int hvfb_set_par(struct fb_info *info)
+{
+       struct hv_device *hdev = device_to_hv_device(info->device);
+
+       return synthvid_send_situ(hdev);
+}
+
+
+static inline u32 chan_to_field(u32 chan, struct fb_bitfield *bf)
+{
+       return ((chan & 0xffff) >> (16 - bf->length)) << bf->offset;
+}
+
+static int hvfb_setcolreg(unsigned regno, unsigned red, unsigned green,
+                         unsigned blue, unsigned transp, struct fb_info *info)
+{
+       u32 *pal = info->pseudo_palette;
+
+       if (regno > 15)
+               return -EINVAL;
+
+       pal[regno] = chan_to_field(red, &info->var.red)
+               | chan_to_field(green, &info->var.green)
+               | chan_to_field(blue, &info->var.blue)
+               | chan_to_field(transp, &info->var.transp);
+
+       return 0;
+}
+
+
+static struct fb_ops hvfb_ops = {
+       .owner = THIS_MODULE,
+       .fb_check_var = hvfb_check_var,
+       .fb_set_par = hvfb_set_par,
+       .fb_setcolreg = hvfb_setcolreg,
+       .fb_fillrect = cfb_fillrect,
+       .fb_copyarea = cfb_copyarea,
+       .fb_imageblit = cfb_imageblit,
+};
+
+
+/* Get options from kernel paramenter "video=" */
+static void hvfb_get_option(struct fb_info *info)
+{
+       struct hvfb_par *par = info->par;
+       char *opt = NULL, *p;
+       uint x = 0, y = 0;
+
+       if (fb_get_options(KBUILD_MODNAME, &opt) || !opt || !*opt)
+               return;
+
+       p = strsep(&opt, "x");
+       if (!*p || kstrtouint(p, 0, &x) ||
+           !opt || !*opt || kstrtouint(opt, 0, &y)) {
+               pr_err("Screen option is invalid: skipped\n");
+               return;
+       }
+
+       if (x < HVFB_WIDTH_MIN || y < HVFB_HEIGHT_MIN ||
+           (par->synthvid_version == SYNTHVID_VERSION_WIN8 &&
+            x * y * screen_depth / 8 > SYNTHVID_FB_SIZE_WIN8) ||
+           (par->synthvid_version == SYNTHVID_VERSION_WIN7 &&
+            (x > SYNTHVID_WIDTH_MAX_WIN7 || y > SYNTHVID_HEIGHT_MAX_WIN7))) {
+               pr_err("Screen resolution option is out of range: skipped\n");
+               return;
+       }
+
+       screen_width = x;
+       screen_height = y;
+       return;
+}
+
+
+/* Get framebuffer memory from Hyper-V video pci space */
+static int hvfb_getmem(struct fb_info *info)
+{
+       struct pci_dev *pdev;
+       ulong fb_phys;
+       void __iomem *fb_virt;
+
+       pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT,
+                             PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
+       if (!pdev) {
+               pr_err("Unable to find PCI Hyper-V video\n");
+               return -ENODEV;
+       }
+
+       if (!(pci_resource_flags(pdev, 0) & IORESOURCE_MEM) ||
+           pci_resource_len(pdev, 0) < screen_fb_size)
+               goto err1;
+
+       fb_phys = pci_resource_end(pdev, 0) - screen_fb_size + 1;
+       if (!request_mem_region(fb_phys, screen_fb_size, KBUILD_MODNAME))
+               goto err1;
+
+       fb_virt = ioremap(fb_phys, screen_fb_size);
+       if (!fb_virt)
+               goto err2;
+
+       info->apertures = alloc_apertures(1);
+       if (!info->apertures)
+               goto err3;
+
+       info->apertures->ranges[0].base = pci_resource_start(pdev, 0);
+       info->apertures->ranges[0].size = pci_resource_len(pdev, 0);
+       info->fix.smem_start = fb_phys;
+       info->fix.smem_len = screen_fb_size;
+       info->screen_base = fb_virt;
+       info->screen_size = screen_fb_size;
+
+       pci_dev_put(pdev);
+       return 0;
+
+err3:
+       iounmap(fb_virt);
+err2:
+       release_mem_region(fb_phys, screen_fb_size);
+err1:
+       pci_dev_put(pdev);
+       return -ENOMEM;
+}
+
+/* Release the framebuffer */
+static void hvfb_putmem(struct fb_info *info)
+{
+       iounmap(info->screen_base);
+       release_mem_region(info->fix.smem_start, screen_fb_size);
+}
+
+
+static int hvfb_probe(struct hv_device *hdev,
+                     const struct hv_vmbus_device_id *dev_id)
+{
+       struct fb_info *info;
+       struct hvfb_par *par;
+       int ret;
+
+       info = framebuffer_alloc(sizeof(struct hvfb_par), &hdev->device);
+       if (!info) {
+               pr_err("No memory for framebuffer info\n");
+               return -ENOMEM;
+       }
+
+       par = info->par;
+       par->info = info;
+       par->fb_ready = false;
+       init_completion(&par->wait);
+       INIT_DELAYED_WORK(&par->dwork, hvfb_update_work);
+
+       /* Connect to VSP */
+       hv_set_drvdata(hdev, info);
+       ret = synthvid_connect_vsp(hdev);
+       if (ret) {
+               pr_err("Unable to connect to VSP\n");
+               goto error1;
+       }
+
+       ret = hvfb_getmem(info);
+       if (ret) {
+               pr_err("No memory for framebuffer\n");
+               goto error2;
+       }
+
+       hvfb_get_option(info);
+       pr_info("Screen resolution: %dx%d, Color depth: %d\n",
+               screen_width, screen_height, screen_depth);
+
+
+       /* Set up fb_info */
+       info->flags = FBINFO_DEFAULT;
+
+       info->var.xres_virtual = info->var.xres = screen_width;
+       info->var.yres_virtual = info->var.yres = screen_height;
+       info->var.bits_per_pixel = screen_depth;
+
+       if (info->var.bits_per_pixel == 16) {
+               info->var.red = (struct fb_bitfield){11, 5, 0};
+               info->var.green = (struct fb_bitfield){5, 6, 0};
+               info->var.blue = (struct fb_bitfield){0, 5, 0};
+               info->var.transp = (struct fb_bitfield){0, 0, 0};
+       } else {
+               info->var.red = (struct fb_bitfield){16, 8, 0};
+               info->var.green = (struct fb_bitfield){8, 8, 0};
+               info->var.blue = (struct fb_bitfield){0, 8, 0};
+               info->var.transp = (struct fb_bitfield){24, 8, 0};
+       }
+
+       info->var.activate = FB_ACTIVATE_NOW;
+       info->var.height = -1;
+       info->var.width = -1;
+       info->var.vmode = FB_VMODE_NONINTERLACED;
+
+       strcpy(info->fix.id, KBUILD_MODNAME);
+       info->fix.type = FB_TYPE_PACKED_PIXELS;
+       info->fix.visual = FB_VISUAL_TRUECOLOR;
+       info->fix.line_length = screen_width * screen_depth / 8;
+       info->fix.accel = FB_ACCEL_NONE;
+
+       info->fbops = &hvfb_ops;
+       info->pseudo_palette = par->pseudo_palette;
+
+       /* Send config to host */
+       ret = synthvid_send_config(hdev);
+       if (ret)
+               goto error;
+
+       ret = register_framebuffer(info);
+       if (ret) {
+               pr_err("Unable to register framebuffer\n");
+               goto error;
+       }
+
+       par->fb_ready = true;
+
+       return 0;
+
+error:
+       hvfb_putmem(info);
+error2:
+       vmbus_close(hdev->channel);
+error1:
+       cancel_delayed_work_sync(&par->dwork);
+       hv_set_drvdata(hdev, NULL);
+       framebuffer_release(info);
+       return ret;
+}
+
+
+static int hvfb_remove(struct hv_device *hdev)
+{
+       struct fb_info *info = hv_get_drvdata(hdev);
+       struct hvfb_par *par = info->par;
+
+       par->update = false;
+       par->fb_ready = false;
+
+       unregister_framebuffer(info);
+       cancel_delayed_work_sync(&par->dwork);
+
+       vmbus_close(hdev->channel);
+       hv_set_drvdata(hdev, NULL);
+
+       hvfb_putmem(info);
+       framebuffer_release(info);
+
+       return 0;
+}
+
+
+static const struct hv_vmbus_device_id id_table[] = {
+       /* Synthetic Video Device GUID */
+       {HV_SYNTHVID_GUID},
+       {}
+};
+
+MODULE_DEVICE_TABLE(vmbus, id_table);
+
+static struct hv_driver hvfb_drv = {
+       .name = KBUILD_MODNAME,
+       .id_table = id_table,
+       .probe = hvfb_probe,
+       .remove = hvfb_remove,
+};
+
+
+static int __init hvfb_drv_init(void)
+{
+       return vmbus_driver_register(&hvfb_drv);
+}
+
+static void __exit hvfb_drv_exit(void)
+{
+       vmbus_driver_unregister(&hvfb_drv);
+}
+
+module_init(hvfb_drv_init);
+module_exit(hvfb_drv_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_VERSION(HV_DRV_VERSION);
+MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Video Frame Buffer Driver");