-/*****************************************************************************
- *                          DLFB Kernel Driver                               *
- *                            Version 0.2 (udlfb)                            *
- *             (C) 2009 Roberto De Ioris <roberto@unbit.it>                  *
- *                                                                           *
- *     This file is licensed under the GPLv2. See COPYING in the package.    *
- * Based on the amazing work of Florian Echtler and libdlo 0.1               *
- *                                                                           *
- *                                                                           *
- * 10.06.09 release 0.2.3 (edid ioctl, fallback for unsupported modes)       *
- * 05.06.09 release 0.2.2 (real screen blanking, rle compression, double buffer) *
- * 31.05.09 release 0.2                                                      *
- * 22.05.09 First public (ugly) release                                      *
- *****************************************************************************/
+/*
+ * udlfb.c -- Framebuffer driver for DisplayLink USB controller
+ *
+ * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
+ * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License v2. See the file COPYING in the main directory of this archive for
+ * more details.
+ *
+ * Layout is based on skeletonfb by James Simmons and Geert Uytterhoeven,
+ * usb-skeleton by GregKH.
+ *
+ * Device-specific portions based on information from Displaylink, with work
+ * from Florian Echtler, Henrik Bjerregaard Pedersen, and others.
+ */
 
 #include <linux/module.h>
 #include <linux/kernel.h>
 
 #include "udlfb.h"
 
-#define DRIVER_VERSION "DLFB 0.2"
+#define DRIVER_VERSION "DisplayLink Framebuffer Driver 0.4.1"
+
+static struct fb_fix_screeninfo dlfb_fix = {
+       .id =           "displaylinkfb",
+       .type =         FB_TYPE_PACKED_PIXELS,
+       .visual =       FB_VISUAL_TRUECOLOR,
+       .xpanstep =     0,
+       .ypanstep =     0,
+       .ywrapstep =    0,
+       .accel =        FB_ACCEL_NONE,
+};
 
-/* memory functions taken from vfb */
+#define NR_USB_REQUEST_I2C_SUB_IO 0x02
+#define NR_USB_REQUEST_CHANNEL 0x12
 
-static void *rvmalloc(unsigned long size)
+/*
+ * Inserts a specific DisplayLink controller command into the provided
+ * buffer.
+ */
+static char *insert_command(char *buf, u8 reg, u8 val)
 {
-       void *mem;
-       unsigned long adr;
+       *buf++ = 0xAF;
+       *buf++ = 0x20;
+       *buf++ = reg;
+       *buf++ = val;
+       return buf;
+}
 
-       size = PAGE_ALIGN(size);
-       mem = vmalloc_32(size);
-       if (!mem)
-               return NULL;
+static char *insert_vidreg_lock(char *buf)
+{
+       return insert_command(buf, 0xFF, 0x00);
+}
 
-       memset(mem, 0, size);   /* Clear the ram out, no junk to the user */
-       adr = (unsigned long)mem;
-       while (size > 0) {
-               SetPageReserved(vmalloc_to_page((void *)adr));
-               adr += PAGE_SIZE;
-               size -= PAGE_SIZE;
+static char *insert_vidreg_unlock(char *buf)
+{
+       return insert_command(buf, 0xFF, 0xFF);
+}
+
+/*
+ * Once you send this command, the DisplayLink framebuffer gets driven to the
+ * display.
+ */
+static char *insert_enable_hvsync(char *buf)
+{
+       return insert_command(buf, 0x1F, 0x00);
+}
+
+static char *insert_set_color_depth(char *buf, u8 selection)
+{
+       return insert_command(buf, 0x00, selection);
+}
+
+static char *insert_set_base16bpp(char *wrptr, u32 base)
+{
+       /* the base pointer is 16 bits wide, 0x20 is hi byte. */
+       wrptr = insert_command(wrptr, 0x20, base >> 16);
+       wrptr = insert_command(wrptr, 0x21, base >> 8);
+       return insert_command(wrptr, 0x22, base);
+}
+
+static char *insert_set_base8bpp(char *wrptr, u32 base)
+{
+       wrptr = insert_command(wrptr, 0x26, base >> 16);
+       wrptr = insert_command(wrptr, 0x27, base >> 8);
+       return insert_command(wrptr, 0x28, base);
+}
+
+static char *insert_command_16(char *wrptr, u8 reg, u16 value)
+{
+       wrptr = insert_command(wrptr, reg, value >> 8);
+       return insert_command(wrptr, reg+1, value);
+}
+
+/*
+ * This is kind of weird because the controller takes some
+ * register values in a different byte order than other registers.
+ */
+static char *insert_command_16be(char *wrptr, u8 reg, u16 value)
+{
+       wrptr = insert_command(wrptr, reg, value);
+       return insert_command(wrptr, reg+1, value >> 8);
+}
+
+/*
+ * LFSR is linear feedback shift register. The reason we have this is
+ * because the display controller needs to minimize the clock depth of
+ * various counters used in the display path. So this code reverses the
+ * provided value into the lfsr16 value by counting backwards to get
+ * the value that needs to be set in the hardware comparator to get the
+ * same actual count. This makes sense once you read above a couple of
+ * times and think about it from a hardware perspective.
+ */
+static u16 lfsr16(u16 actual_count)
+{
+       u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
+
+       while (actual_count--) {
+               lv =     ((lv << 1) |
+                       (((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
+                       & 0xFFFF;
        }
 
-       return mem;
+       return (u16) lv;
+}
+
+/*
+ * This does LFSR conversion on the value that is to be written.
+ * See LFSR explanation above for more detail.
+ */
+static char *insert_command_lfsr16(char *wrptr, u8 reg, u16 value)
+{
+       return insert_command_16(wrptr, reg, lfsr16(value));
 }
 
-static void rvfree(void *mem, unsigned long size)
+/*
+ * This takes a standard fbdev screeninfo struct and all of its monitor mode
+ * details and converts them into the DisplayLink equivalent register commands.
+ */
+static char *insert_set_vid_cmds(char *wrptr, struct fb_var_screeninfo *var)
 {
-       unsigned long adr;
+       u16 xds, yds;
+       u16 xde, yde;
+       u16 yec;
+
+
+       /* x display start */
+       xds = var->left_margin + var->hsync_len;
+       wrptr = insert_command_lfsr16(wrptr, 0x01, xds);
+       /* x display end */
+       xde = xds + var->xres;
+       wrptr = insert_command_lfsr16(wrptr, 0x03, xde);
+
+       /* y display start */
+       yds = var->upper_margin + var->vsync_len;
+       wrptr = insert_command_lfsr16(wrptr, 0x05, yds);
+       /* y display end */
+       yde = yds + var->yres;
+       wrptr = insert_command_lfsr16(wrptr, 0x07, yde);
+
+       /* x end count is active + blanking - 1 */
+       wrptr = insert_command_lfsr16(wrptr, 0x09, xde + var->right_margin - 1);
+
+       /* libdlo hardcodes hsync start to 1 */
+       wrptr = insert_command_lfsr16(wrptr, 0x0B, 1);
+
+       /* hsync end is width of sync pulse + 1 */
+       wrptr = insert_command_lfsr16(wrptr, 0x0D, var->hsync_len + 1);
+
+       /* hpixels is active pixels */
+       wrptr = insert_command_16(wrptr, 0x0F, var->xres);
 
-       if (!mem)
-               return;
+       /* yendcount is vertical active + vertical blanking */
+       yec = var->yres + var->upper_margin + var->lower_margin +
+                       var->vsync_len;
+       wrptr = insert_command_lfsr16(wrptr, 0x11, yec);
 
-       adr = (unsigned long)mem;
-       while ((long)size > 0) {
-               ClearPageReserved(vmalloc_to_page((void *)adr));
-               adr += PAGE_SIZE;
-               size -= PAGE_SIZE;
+       /* libdlo hardcodes vsync start to 0 */
+       wrptr = insert_command_lfsr16(wrptr, 0x13, 0);
+
+       /* vsync end is width of vsync pulse */
+       wrptr = insert_command_lfsr16(wrptr, 0x15, var->vsync_len);
+
+       /* vpixels is active pixels */
+       wrptr = insert_command_16(wrptr, 0x17, var->yres);
+
+       /* convert picoseconds to 5kHz multiple for pclk5k = x * 1E12/5k */
+       wrptr = insert_command_16be(wrptr, 0x1B, 200*1000*1000/var->pixclock);
+
+       return wrptr;
+}
+
+/*
+ * This takes a standard fbdev screeninfo struct that was fetched or prepared
+ * and then generates the appropriate command sequence that then drives the
+ * display controller.
+ */
+static int dlfb_set_video_mode(struct dlfb_data *dev,
+                               struct fb_var_screeninfo *var)
+{
+       char *buf;
+       char *wrptr;
+       int retval = 0;
+       int writesize;
+
+       buf = dev->buf;
+
+       /*
+       * This first section has to do with setting the base address on the
+       * controller * associated with the display. There are 2 base
+       * pointers, currently, we only * use the 16 bpp segment.
+       */
+       wrptr = insert_vidreg_lock(buf);
+       wrptr = insert_set_color_depth(wrptr, 0x00);
+       /* set base for 16bpp segment to 0 */
+       wrptr = insert_set_base16bpp(wrptr, 0);
+       /* set base for 8bpp segment to end of fb */
+       wrptr = insert_set_base8bpp(wrptr, dev->info->fix.smem_len);
+
+       wrptr = insert_set_vid_cmds(wrptr, var);
+       wrptr = insert_enable_hvsync(wrptr);
+       wrptr = insert_vidreg_unlock(wrptr);
+
+       writesize = wrptr - buf;
+
+       mutex_lock(&dev->bulk_mutex);
+       if (!dev->interface) {          /* disconnect() was called */
+               mutex_unlock(&dev->bulk_mutex);
+               retval = -ENODEV;
+               goto error;
        }
-       vfree(mem);
+
+       retval = dlfb_bulk_msg(dev, writesize);
+       mutex_unlock(&dev->bulk_mutex);
+       if (retval) {
+               dev_err(&dev->udev->dev, "Problem %d with submit write bulk.\n",
+                                       retval);
+               goto error;
+       }
+
+       return 0;
+
+error:
+       return retval;
+}
+
+/*
+ * This is necessary before we can communicate with the display controller.
+ */
+static int dlfb_select_std_channel(struct dlfb_data *dev)
+{
+       int ret;
+       u8 set_def_chn[] = {       0x57, 0xCD, 0xDC, 0xA7,
+                               0x1C, 0x88, 0x5E, 0x15,
+                               0x60, 0xFE, 0xC6, 0x97,
+                               0x16, 0x3D, 0x47, 0xF2  };
+
+       ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
+                       NR_USB_REQUEST_CHANNEL,
+                       (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
+                       set_def_chn, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
+       return ret;
+}
+
+
+/*
+ * Query EDID from the handware, then hand it off to fbdev's edid parse
+ * routine which should give us back a filled in screeninfo structure.
+ */
+static int dlfb_get_var_from_edid(struct dlfb_data *dev,
+                                       struct fb_var_screeninfo *var)
+{
+       int ret;
+
+       dlfb_edid(dev);
+       ret = fb_parse_edid(dev->edid, var);
+
+       return ret;
 }
 
 static int dlfb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 };
 
 /*
-static struct usb_device_id id_table [] = {
-       { USB_DEVICE(0x17e9, 0x023d) },
-       { }
-};
-*/
-
+ * There are many DisplayLink-based products, all with unique PIDs. We are able
+ * to support all volume ones (circa 2009) with a single driver, so we match
+ * globally on VID. TODO: Probe() needs to detect when we might be running
+ * "future" chips, and bail on those, so a compatible driver can match.
+ */
 static struct usb_device_id id_table[] = {
        {.idVendor = 0x17e9, .match_flags = USB_DEVICE_ID_MATCH_VENDOR,},
        {},
                        if (thistime > 255)
                                thistime = 255;
 
-                       // find position of first pixel that has changed
-                       firstdiff = -1;
-                       for (j = 0; j < thistime * 2; j++) {
-                               if (dev_info->backing_buffer
-                                   [base - dev_info->base16 + j] != data[j]) {
-                                       firstdiff = j / 2;
-                                       break;
+                       if (dev_info->backing_buffer) {
+                               /* find first pixel that has changed */
+                               firstdiff = -1;
+                               for (j = 0; j < thistime * 2; j++) {
+                                       if (dev_info->backing_buffer
+                                           [base - dev_info->base16 + j]
+                                           != data[j]) {
+                                               firstdiff = j / 2;
+                                               break;
+                                       }
                                }
+
+                       } else {
+                               firstdiff = 0;
+
                        }
 
                        if (firstdiff >= 0) {
                        rem -= thistime;
                }
 
-               memcpy(dev_info->backing_buffer + (base - dev_info->base16) -
-                      (width * 2), data - (width * 2), width * 2);
+               if (dev_info->backing_buffer)
+                       memcpy(dev_info->backing_buffer +
+                              (base - dev_info->base16) -
+                              (width * 2), data - (width * 2), width * 2);
 
                base += (dev_info->info->var.xres * 2) - (width * 2);
                data += (dev_info->info->var.xres * 2) - (width * 2);
 
        for (i = y; i < y + height; i++) {
 
-               for (j = 0; j < width * 2; j += 2) {
-                       dev_info->backing_buffer[base - dev_info->base16 + j] =
-                           (char)(col >> 8);
-                       dev_info->backing_buffer[base - dev_info->base16 + j +
-                                                1] = (char)(col);
+               if (dev_info->backing_buffer) {
+                       for (j = 0; j < width * 2; j += 2) {
+                               dev_info->backing_buffer
+                                       [base - dev_info->base16 + j] =
+                                       (char)(col >> 8);
+                               dev_info->backing_buffer
+                                       [base - dev_info->base16 + j + 1] =
+                                       (char)(col);
+                       }
                }
+
                if (dev_info->bufend - bufptr < BUF_HIGH_WATER_MARK) {
                        ret = dlfb_bulk_msg(dev_info, bufptr - dev_info->buf);
                        bufptr = dev_info->buf;
        .fb_blank = dlfb_blank,
 };
 
-static int
-dlfb_probe(struct usb_interface *interface, const struct usb_device_id *id)
+static int dlfb_probe(struct usb_interface *interface,
+                       const struct usb_device_id *id)
 {
-       struct dlfb_data *dev_info;
+       struct device *mydev;
+       struct usb_device *usbdev;
+       struct dlfb_data *dev;
        struct fb_info *info;
-
-       int ret;
-       char rbuf[4];
-
-       dev_info = kzalloc(sizeof(*dev_info), GFP_KERNEL);
-       if (dev_info == NULL) {
-               printk("cannot allocate dev_info structure.\n");
-               return -ENOMEM;
-       }
-
-       mutex_init(&dev_info->bulk_mutex);
-
-       dev_info->udev = usb_get_dev(interface_to_usbdev(interface));
-       dev_info->interface = interface;
-
-       printk("DisplayLink device attached\n");
-
-       /* add framebuffer info to usb interface */
-       usb_set_intfdata(interface, dev_info);
-
-       dev_info->buf = kmalloc(BUF_SIZE, GFP_KERNEL);
-       /* usb_buffer_alloc(dev_info->udev, BUF_SIZE , GFP_KERNEL, &dev_info->tx_urb->transfer_dma); */
-
-       if (dev_info->buf == NULL) {
-               printk("unable to allocate memory for dlfb commands\n");
-               goto out;
+       int videomemorysize;
+       unsigned char *videomemory;
+       int retval = -ENOMEM;
+       struct fb_var_screeninfo *var;
+       struct fb_bitfield red = { 11, 5, 0 };
+       struct fb_bitfield green = { 5, 6, 0 };
+       struct fb_bitfield blue = { 0, 5, 0 };
+
+       usbdev = usb_get_dev(interface_to_usbdev(interface));
+       mydev = &usbdev->dev;
+
+       dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+       if (dev == NULL) {
+               dev_err(mydev, "failed alloc of dev struct\n");
+               goto err_devalloc;
        }
-       dev_info->bufend = dev_info->buf + BUF_SIZE;
-
-       dev_info->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
-       usb_fill_bulk_urb(dev_info->tx_urb, dev_info->udev,
-                         usb_sndbulkpipe(dev_info->udev, 1), dev_info->buf, 0,
-                         dlfb_bulk_callback, dev_info);
-
-       ret =
-           usb_control_msg(dev_info->udev, usb_rcvctrlpipe(dev_info->udev, 0),
-                           (0x06), (0x80 | (0x02 << 5)), 0, 0, rbuf, 4, 0);
-       printk("ret control msg 0: %d %x%x%x%x\n", ret, rbuf[0], rbuf[1],
-              rbuf[2], rbuf[3]);
 
-       dlfb_edid(dev_info);
-
-       info = framebuffer_alloc(sizeof(u32) * 256, &dev_info->udev->dev);
-
-       if (!info) {
-               printk("non posso allocare il framebuffer displaylink");
-               goto out;
+       mutex_init(&dev->bulk_mutex);
+       dev->udev = usbdev;
+       dev->interface = interface;
+       usb_set_intfdata(interface, dev);
+
+       dev_info(mydev, "dlfb_probe: setting up DisplayLink device\n");
+
+       /*
+        * TODO: replace single 64K buffer with buffer list
+        * and async dispatch
+        */
+       dev->buf = kmalloc(BUF_SIZE, GFP_KERNEL);
+       if (dev->buf == NULL) {
+               dev_err(mydev, "unable to allocate memory for dlfb commands\n");
+               goto err_usballoc;
        }
-
-       fb_parse_edid(dev_info->edid, &info->var);
-
-       printk("EDID XRES %d YRES %d\n", info->var.xres, info->var.yres);
-
-       if (dlfb_set_video_mode(dev_info, info->var.xres, info->var.yres) != 0) {
-               info->var.xres = 1280;
-               info->var.yres = 1024;
-               if (dlfb_set_video_mode
-                   (dev_info, info->var.xres, info->var.yres) != 0) {
-                       goto out;
-               }
+       dev->bufend = dev->buf + BUF_SIZE;
+
+       dev->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
+       usb_fill_bulk_urb(dev->tx_urb, dev->udev,
+                         usb_sndbulkpipe(dev->udev, 1), dev->buf, 0,
+                         dlfb_bulk_callback, dev);
+
+       /* allocates framebuffer driver structure, not framebuffer memory */
+       info = framebuffer_alloc(0, mydev);
+       if (!info)
+               goto err_fballoc;
+
+       dev->info = info;
+       info->par = dev;
+       info->pseudo_palette = dev->pseudo_palette;
+
+       var = &info->var;
+       retval = dlfb_get_var_from_edid(dev, var);
+       if (retval) {
+               /* had a problem getting edid. so fallback to 640x480 */
+               dev_err(mydev, "Problem %d with EDID.\n", retval);
+               var->xres = 640;
+               var->yres = 480;
        }
 
-       printk("found valid mode...%d\n", info->var.pixclock);
-
-       info->pseudo_palette = info->par;
-       info->par = dev_info;
-
-       dev_info->info = info;
-
+       /*
+        * ok, now that we've got the size info, we can alloc our framebuffer.
+        * We are using 16bpp.
+        */
+       info->var.bits_per_pixel = 16;
+       info->fix = dlfb_fix;
+       info->fix.line_length = var->xres * (var->bits_per_pixel / 8);
+       videomemorysize = info->fix.line_length * var->yres;
+
+       /*
+        * The big chunk of system memory we use as a virtual framebuffer.
+        * Pages don't need to be set RESERVED (non-swap) immediately on 2.6
+        * remap_pfn_page() syscall in our mmap and/or defio will handle.
+        */
+       videomemory = vmalloc(videomemorysize);
+       if (!videomemory)
+               goto err_vidmem;
+       memset(videomemory, 0, videomemorysize);
+
+       info->screen_base = videomemory;
+       info->fix.smem_len = PAGE_ALIGN(videomemorysize);
+       info->fix.smem_start = (unsigned long) videomemory;
        info->flags =
            FBINFO_DEFAULT | FBINFO_READS_FAST | FBINFO_HWACCEL_IMAGEBLIT |
            FBINFO_HWACCEL_COPYAREA | FBINFO_HWACCEL_FILLRECT;
-       info->fbops = &dlfb_ops;
-       info->screen_base = rvmalloc(dev_info->screen_size);
 
-       if (info->screen_base == NULL) {
-               printk
-                   ("cannot allocate framebuffer virtual memory of %d bytes\n",
-                    dev_info->screen_size);
-               goto out0;
-       }
-
-       printk("screen base allocated !!!\n");
-
-       dev_info->backing_buffer = kzalloc(dev_info->screen_size, GFP_KERNEL);
-
-       if (!dev_info->backing_buffer)
-               printk("non posso allocare il backing buffer\n");
+       /*
+        * Second framebuffer copy, mirroring the state of the framebuffer
+        * on the physical USB device. We can function without this.
+        * But with imperfect damage info we may end up sending pixels over USB
+        * that were, in fact, unchanged -- wasting limited USB bandwidth
+        */
+       dev->backing_buffer = vmalloc(dev->screen_size);
+       if (!dev->backing_buffer)
+               dev_info(mydev, "No backing buffer allocated!\n");
 
-       /* info->var = dev_info->si; */
-
-       info->var.bits_per_pixel = 16;
-       info->var.activate = FB_ACTIVATE_TEST;
-       info->var.vmode = FB_VMODE_NONINTERLACED;
+       info->fbops = &dlfb_ops;
 
-       info->var.red.offset = 11;
-       info->var.red.length = 5;
-       info->var.red.msb_right = 0;
+       var->vmode = FB_VMODE_NONINTERLACED;
+       var->red = red;
+       var->green = green;
+       var->blue = blue;
 
-       info->var.green.offset = 5;
-       info->var.green.length = 6;
-       info->var.green.msb_right = 0;
+       /*
+        * TODO: Enable FB_CONFIG_DEFIO support
 
-       info->var.blue.offset = 0;
-       info->var.blue.length = 5;
-       info->var.blue.msb_right = 0;
+        info->fbdefio = &dlfb_defio;
+        fb_deferred_io_init(info);
 
-       /* info->var.pixclock =  (10000000 / FB_W * 1000 / FB_H)/2 ; */
+        */
 
-       info->fix.smem_start = (unsigned long)info->screen_base;
-       info->fix.smem_len = PAGE_ALIGN(dev_info->screen_size);
-       if (strlen(dev_info->udev->product) > 15) {
-               memcpy(info->fix.id, dev_info->udev->product, 15);
-       } else {
-               memcpy(info->fix.id, dev_info->udev->product,
-                      strlen(dev_info->udev->product));
+       retval = fb_alloc_cmap(&info->cmap, 256, 0);
+       if (retval < 0) {
+               dev_err(mydev, "Failed to allocate colormap\n");
+               goto err_cmap;
        }
-       info->fix.type = FB_TYPE_PACKED_PIXELS;
-       info->fix.visual = FB_VISUAL_TRUECOLOR;
-       info->fix.accel = info->flags;
-       info->fix.line_length = dev_info->line_length;
 
-       if (fb_alloc_cmap(&info->cmap, 256, 0) < 0)
-               goto out1;
+       dlfb_select_std_channel(dev);
+       dlfb_set_video_mode(dev, var);
+       /* TODO: dlfb_dpy_update(dev); */
 
-       printk("colormap allocated\n");
-       if (register_framebuffer(info) < 0)
-               goto out2;
+       retval = register_framebuffer(info);
+       if (retval < 0)
+               goto err_regfb;
 
-       draw_rect(dev_info, 0, 0, dev_info->info->var.xres,
-                 dev_info->info->var.yres, 0x30, 0xff, 0x30);
+       /* paint "successful" green screen */
+       draw_rect(dev, 0, 0, dev->info->var.xres,
+                 dev->info->var.yres, 0x30, 0xff, 0x30);
 
+       dev_info(mydev, "DisplayLink USB device %d now attached, "
+                       "using %dK of memory\n", info->node,
+                ((dev->backing_buffer) ?
+                 videomemorysize * 2 : videomemorysize) >> 10);
        return 0;
 
-out2:
+err_regfb:
        fb_dealloc_cmap(&info->cmap);
-out1:
-       rvfree(info->screen_base, dev_info->screen_size);
-out0:
+err_cmap:
+       /* TODO: fb_deferred_io_cleanup(info); */
+       vfree(videomemory);
+err_vidmem:
        framebuffer_release(info);
-out:
+err_fballoc:
+       kfree(dev->buf);
+err_usballoc:
        usb_set_intfdata(interface, NULL);
-       usb_put_dev(dev_info->udev);
-       kfree(dev_info);
-       return -ENOMEM;
-
+       usb_put_dev(dev->udev);
+       kfree(dev);
+err_devalloc:
+       return retval;
 }
 
 static void dlfb_disconnect(struct usb_interface *interface)
 {
-       struct dlfb_data *dev_info = usb_get_intfdata(interface);
-
-       mutex_unlock(&dev_info->bulk_mutex);
+       struct dlfb_data *dev;
+       struct fb_info *info;
 
-       usb_kill_urb(dev_info->tx_urb);
-       usb_free_urb(dev_info->tx_urb);
+       dev = usb_get_intfdata(interface);
        usb_set_intfdata(interface, NULL);
-       usb_put_dev(dev_info->udev);
-
-       if (dev_info->info) {
-               unregister_framebuffer(dev_info->info);
-               fb_dealloc_cmap(&dev_info->info->cmap);
-               rvfree(dev_info->info->screen_base, dev_info->screen_size);
-               kfree(dev_info->backing_buffer);
-               framebuffer_release(dev_info->info);
-
+       usb_put_dev(dev->udev);
+
+       /*
+        * TODO: since, upon usb disconnect(), usb will cancel in-flight urbs
+        * and error out any new ones, look at eliminating need for mutex
+        */
+       mutex_lock(&dev->bulk_mutex);
+       dev->interface = NULL;
+       info = dev->info;
+       mutex_unlock(&dev->bulk_mutex);
+
+       if (info) {
+               dev_info(&interface->dev, "Detaching DisplayLink device %d.\n",
+                                               info->node);
+               unregister_framebuffer(info);
+               fb_dealloc_cmap(&info->cmap);
+               /* TODO: fb_deferred_io_cleanup(info); */
+               fb_dealloc_cmap(&info->cmap);
+               vfree((void __force *)info->screen_base);
+               framebuffer_release(info);
        }
 
-       kfree(dev_info);
+       if (dev->backing_buffer)
+               vfree(dev->backing_buffer);
 
-       printk("DisplayLink device disconnected\n");
+       kfree(dev);
 }
 
 static struct usb_driver dlfb_driver = {
 {
        int res;
 
-       dlfb_init_modes();
-
        res = usb_register(&dlfb_driver);
        if (res)
                err("usb_register failed. Error number %d", res);
 module_init(dlfb_init);
 module_exit(dlfb_exit);
 
-MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>");
+MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
+             "Jaya Kumar <jayakumar.lkml@gmail.com>");
 MODULE_DESCRIPTION(DRIVER_VERSION);
 MODULE_LICENSE("GPL");
 
 #ifndef UDLFB_H
 #define UDLFB_H
 
-#define MAX_VMODES     4
-#define FB_BPP         16
-
-#define STD_CHANNEL    "\x57\xCD\xDC\xA7\x1C\x88\x5E\x15"      \
-                       "\x60\xFE\xC6\x97\x16\x3D\x47\xF2"
-
 /* as libdlo */
 #define BUF_HIGH_WATER_MARK    1024
 #define BUF_SIZE               (64*1024)
        int base16d;
        int base8;
        int base8d;
+       u32 pseudo_palette[256];
 };
 
-struct dlfb_video_mode {
-       uint8_t col;
-       uint32_t hclock;
-       uint32_t vclock;
-       uint8_t unknown1[6];
-       uint16_t xres;
-       uint8_t unknown2[6];
-       uint16_t yres;
-       uint8_t unknown3[4];
-} __attribute__ ((__packed__));
-
-static struct dlfb_video_mode dlfb_video_modes[MAX_VMODES];
-
 static void dlfb_bulk_callback(struct urb *urb)
 {
        struct dlfb_data *dev_info = urb->context;
        return dev_info->tx_urb->actual_length;
 }
 
-static void dlfb_init_modes(void)
-{
-       dlfb_video_modes[0].col = 0;
-       memcpy(&dlfb_video_modes[0].hclock, "\x20\x3C\x7A\xC9", 4);
-       memcpy(&dlfb_video_modes[0].vclock, "\xF2\x6C\x48\xF9", 4);
-       memcpy(&dlfb_video_modes[0].unknown1, "\x70\x53\xFF\xFF\x21\x27", 6);
-       dlfb_video_modes[0].xres = 800;
-       memcpy(&dlfb_video_modes[0].unknown2, "\x91\xF3\xFF\xFF\xFF\xF9", 6);
-       dlfb_video_modes[0].yres = 480;
-       memcpy(&dlfb_video_modes[0].unknown3, "\x01\x02\xC8\x19", 4);
-
-       dlfb_video_modes[1].col = 0;
-       memcpy(&dlfb_video_modes[1].hclock, "\x36\x18\xD5\x10", 4);
-       memcpy(&dlfb_video_modes[1].vclock, "\x60\xA9\x7B\x33", 4);
-       memcpy(&dlfb_video_modes[1].unknown1, "\xA1\x2B\x27\x32\xFF\xFF", 6);
-       dlfb_video_modes[1].xres = 1024;
-       memcpy(&dlfb_video_modes[1].unknown2, "\xD9\x9A\xFF\xCA\xFF\xFF", 6);
-       dlfb_video_modes[1].yres = 768;
-       memcpy(&dlfb_video_modes[1].unknown3, "\x04\x03\xC8\x32", 4);
-
-       dlfb_video_modes[2].col = 0;
-       memcpy(&dlfb_video_modes[2].hclock, "\x98\xF8\x0D\x57", 4);
-       memcpy(&dlfb_video_modes[2].vclock, "\x2A\x55\x4D\x54", 4);
-       memcpy(&dlfb_video_modes[2].unknown1, "\xCA\x0D\xFF\xFF\x94\x43", 6);
-       dlfb_video_modes[2].xres = 1280;
-       memcpy(&dlfb_video_modes[2].unknown2, "\x9A\xA8\xFF\xFF\xFF\xF9", 6);
-       dlfb_video_modes[2].yres = 1024;
-       memcpy(&dlfb_video_modes[2].unknown3, "\x04\x02\x60\x54", 4);
-
-       dlfb_video_modes[3].col = 0;
-       memcpy(&dlfb_video_modes[3].hclock, "\x42\x24\x38\x36", 4);
-       memcpy(&dlfb_video_modes[3].vclock, "\xC1\x52\xD9\x29", 4);
-       memcpy(&dlfb_video_modes[3].unknown1, "\xEA\xB8\x32\x60\xFF\xFF", 6);
-       dlfb_video_modes[3].xres = 1400;
-       memcpy(&dlfb_video_modes[3].unknown2, "\xC9\x4E\xFF\xFF\xFF\xF2", 6);
-       dlfb_video_modes[3].yres = 1050;
-       memcpy(&dlfb_video_modes[3].unknown3, "\x04\x02\x1E\x5F", 4);
-}
-
-static char *dlfb_set_register(char *bufptr, uint8_t reg, uint8_t val)
-{
-       *bufptr++ = 0xAF;
-       *bufptr++ = 0x20;
-       *bufptr++ = reg;
-       *bufptr++ = val;
-
-       return bufptr;
-}
-
-static int dlfb_set_video_mode(struct dlfb_data *dev_info, int width, int height)
-{
-       int i, ret;
-       unsigned char j;
-       char *bufptr = dev_info->buf;
-       uint8_t *vdata;
-
-       for (i = 0; i < MAX_VMODES; i++) {
-               printk("INIT VIDEO %d %d %d\n", i, dlfb_video_modes[i].xres,
-                      dlfb_video_modes[i].yres);
-               if (dlfb_video_modes[i].xres == width
-                   && dlfb_video_modes[i].yres == height) {
-
-                       dev_info->base16 = 0;
-                       dev_info->base16d = width * height * (FB_BPP / 8);
-
-                       //dev_info->base8 = width * height * (FB_BPP / 8);
-
-                       dev_info->base8 = dev_info->base16;
-                       dev_info->base8d = dev_info->base16d;
-
-                       /* set encryption key (null) */
-                       memcpy(dev_info->buf, STD_CHANNEL, 16);
-                       ret =
-                           usb_control_msg(dev_info->udev,
-                                           usb_sndctrlpipe(dev_info->udev, 0),
-                                           0x12, (0x02 << 5), 0, 0,
-                                           dev_info->buf, 16, 0);
-                       printk("ret control msg 1 (STD_CHANNEL): %d\n", ret);
-
-                       /* set registers */
-                       bufptr = dlfb_set_register(bufptr, 0xFF, 0x00);
-
-                       /* set color depth */
-                       bufptr = dlfb_set_register(bufptr, 0x00, 0x00);
-
-                       /* set addresses */
-                       bufptr =
-                           dlfb_set_register(bufptr, 0x20,
-                                             (char)(dev_info->base16 >> 16));
-                       bufptr =
-                           dlfb_set_register(bufptr, 0x21,
-                                             (char)(dev_info->base16 >> 8));
-                       bufptr =
-                           dlfb_set_register(bufptr, 0x22,
-                                             (char)(dev_info->base16));
-
-                       bufptr =
-                           dlfb_set_register(bufptr, 0x26,
-                                             (char)(dev_info->base8 >> 16));
-                       bufptr =
-                           dlfb_set_register(bufptr, 0x27,
-                                             (char)(dev_info->base8 >> 8));
-                       bufptr =
-                           dlfb_set_register(bufptr, 0x28,
-                                             (char)(dev_info->base8));
-
-                       /* set video mode */
-                       vdata = (uint8_t *)&dlfb_video_modes[i];
-                       for (j = 0; j < 29; j++)
-                               bufptr = dlfb_set_register(bufptr, j, vdata[j]);
-
-                       /* blank */
-                       bufptr = dlfb_set_register(bufptr, 0x1F, 0x00);
-
-                       /* end registers */
-                       bufptr = dlfb_set_register(bufptr, 0xFF, 0xFF);
-
-                       /* send */
-                       ret = dlfb_bulk_msg(dev_info, bufptr - dev_info->buf);
-                       printk("ret bulk 2: %d %td\n", ret,
-                              bufptr - dev_info->buf);
-
-                       /* flush */
-                       ret = dlfb_bulk_msg(dev_info, 0);
-                       printk("ret bulk 3: %d\n", ret);
-
-                       dev_info->screen_size = width * height * (FB_BPP / 8);
-                       dev_info->line_length = width * (FB_BPP / 8);
-
-                       return 0;
-               }
-       }
-
-       return -1;
-}
+#define dlfb_set_register insert_command
 
 #endif