From: Paul Mundt <lethal@linux-sh.org>
Date: Thu, 6 Jan 2011 09:10:09 +0000 (+0900)
Subject: Merge branch 'fbdev/udlfb'
X-Git-Tag: MMI-PSA29.97-13-9~21444^2~1
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ca9c20ce2b383032b71bdae9ec0b468d428ca8d4;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

Merge branch 'fbdev/udlfb'
---

ca9c20ce2b383032b71bdae9ec0b468d428ca8d4
diff --cc drivers/video/udlfb.c
index 000000000000,74a679ef0f5c..020589a6bf02
mode 000000,100644..100644
--- a/drivers/video/udlfb.c
+++ b/drivers/video/udlfb.c
@@@ -1,0 -1,1879 +1,1879 @@@
+ /*
+  * 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>
+  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.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.
+  */
+ 
+ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+ 
+ #include <linux/module.h>
+ #include <linux/kernel.h>
+ #include <linux/init.h>
+ #include <linux/usb.h>
+ #include <linux/uaccess.h>
+ #include <linux/mm.h>
+ #include <linux/fb.h>
+ #include <linux/vmalloc.h>
+ #include <linux/slab.h>
+ #include <linux/delay.h>
+ #include <video/udlfb.h>
+ #include "edid.h"
+ 
+ static struct fb_fix_screeninfo dlfb_fix = {
+ 	.id =           "udlfb",
+ 	.type =         FB_TYPE_PACKED_PIXELS,
+ 	.visual =       FB_VISUAL_TRUECOLOR,
+ 	.xpanstep =     0,
+ 	.ypanstep =     0,
+ 	.ywrapstep =    0,
+ 	.accel =        FB_ACCEL_NONE,
+ };
+ 
+ static const u32 udlfb_info_flags = FBINFO_DEFAULT | FBINFO_READS_FAST |
+ 		FBINFO_VIRTFB |
+ 		FBINFO_HWACCEL_IMAGEBLIT | FBINFO_HWACCEL_FILLRECT |
+ 		FBINFO_HWACCEL_COPYAREA | FBINFO_MISC_ALWAYS_SETPAR;
+ 
+ /*
+  * 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,},
+ 	{},
+ };
+ MODULE_DEVICE_TABLE(usb, id_table);
+ 
+ /* module options */
+ static int console;   /* Optionally allow fbcon to consume first framebuffer */
+ static int fb_defio;  /* Optionally enable experimental fb_defio mmap support */
+ 
+ /* dlfb keeps a list of urbs for efficient bulk transfers */
+ static void dlfb_urb_completion(struct urb *urb);
+ static struct urb *dlfb_get_urb(struct dlfb_data *dev);
+ static int dlfb_submit_urb(struct dlfb_data *dev, struct urb * urb, size_t len);
+ static int dlfb_alloc_urb_list(struct dlfb_data *dev, int count, size_t size);
+ static void dlfb_free_urb_list(struct dlfb_data *dev);
+ 
+ /*
+  * All DisplayLink bulk operations start with 0xAF, followed by specific code
+  * All operations are written to buffers which then later get sent to device
+  */
+ static char *dlfb_set_register(char *buf, u8 reg, u8 val)
+ {
+ 	*buf++ = 0xAF;
+ 	*buf++ = 0x20;
+ 	*buf++ = reg;
+ 	*buf++ = val;
+ 	return buf;
+ }
+ 
+ static char *dlfb_vidreg_lock(char *buf)
+ {
+ 	return dlfb_set_register(buf, 0xFF, 0x00);
+ }
+ 
+ static char *dlfb_vidreg_unlock(char *buf)
+ {
+ 	return dlfb_set_register(buf, 0xFF, 0xFF);
+ }
+ 
+ /*
+  * On/Off for driving the DisplayLink framebuffer to the display
+  *  0x00 H and V sync on
+  *  0x01 H and V sync off (screen blank but powered)
+  *  0x07 DPMS powerdown (requires modeset to come back)
+  */
+ static char *dlfb_enable_hvsync(char *buf, bool enable)
+ {
+ 	if (enable)
+ 		return dlfb_set_register(buf, 0x1F, 0x00);
+ 	else
+ 		return dlfb_set_register(buf, 0x1F, 0x07);
+ }
+ 
+ static char *dlfb_set_color_depth(char *buf, u8 selection)
+ {
+ 	return dlfb_set_register(buf, 0x00, selection);
+ }
+ 
+ static char *dlfb_set_base16bpp(char *wrptr, u32 base)
+ {
+ 	/* the base pointer is 16 bits wide, 0x20 is hi byte. */
+ 	wrptr = dlfb_set_register(wrptr, 0x20, base >> 16);
+ 	wrptr = dlfb_set_register(wrptr, 0x21, base >> 8);
+ 	return dlfb_set_register(wrptr, 0x22, base);
+ }
+ 
+ /*
+  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
+  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
+  */
+ static char *dlfb_set_base8bpp(char *wrptr, u32 base)
+ {
+ 	wrptr = dlfb_set_register(wrptr, 0x26, base >> 16);
+ 	wrptr = dlfb_set_register(wrptr, 0x27, base >> 8);
+ 	return dlfb_set_register(wrptr, 0x28, base);
+ }
+ 
+ static char *dlfb_set_register_16(char *wrptr, u8 reg, u16 value)
+ {
+ 	wrptr = dlfb_set_register(wrptr, reg, value >> 8);
+ 	return dlfb_set_register(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 *dlfb_set_register_16be(char *wrptr, u8 reg, u16 value)
+ {
+ 	wrptr = dlfb_set_register(wrptr, reg, value);
+ 	return dlfb_set_register(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 dlfb_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 (u16) lv;
+ }
+ 
+ /*
+  * This does LFSR conversion on the value that is to be written.
+  * See LFSR explanation above for more detail.
+  */
+ static char *dlfb_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
+ {
+ 	return dlfb_set_register_16(wrptr, reg, dlfb_lfsr16(value));
+ }
+ 
+ /*
+  * 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 *dlfb_set_vid_cmds(char *wrptr, struct fb_var_screeninfo *var)
+ {
+ 	u16 xds, yds;
+ 	u16 xde, yde;
+ 	u16 yec;
+ 
+ 	/* x display start */
+ 	xds = var->left_margin + var->hsync_len;
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x01, xds);
+ 	/* x display end */
+ 	xde = xds + var->xres;
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x03, xde);
+ 
+ 	/* y display start */
+ 	yds = var->upper_margin + var->vsync_len;
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x05, yds);
+ 	/* y display end */
+ 	yde = yds + var->yres;
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x07, yde);
+ 
+ 	/* x end count is active + blanking - 1 */
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x09,
+ 			xde + var->right_margin - 1);
+ 
+ 	/* libdlo hardcodes hsync start to 1 */
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x0B, 1);
+ 
+ 	/* hsync end is width of sync pulse + 1 */
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x0D, var->hsync_len + 1);
+ 
+ 	/* hpixels is active pixels */
+ 	wrptr = dlfb_set_register_16(wrptr, 0x0F, var->xres);
+ 
+ 	/* yendcount is vertical active + vertical blanking */
+ 	yec = var->yres + var->upper_margin + var->lower_margin +
+ 			var->vsync_len;
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x11, yec);
+ 
+ 	/* libdlo hardcodes vsync start to 0 */
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x13, 0);
+ 
+ 	/* vsync end is width of vsync pulse */
+ 	wrptr = dlfb_set_register_lfsr16(wrptr, 0x15, var->vsync_len);
+ 
+ 	/* vpixels is active pixels */
+ 	wrptr = dlfb_set_register_16(wrptr, 0x17, var->yres);
+ 
+ 	/* convert picoseconds to 5kHz multiple for pclk5k = x * 1E12/5k */
+ 	wrptr = dlfb_set_register_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;
+ 	struct urb *urb;
+ 
+ 	if (!atomic_read(&dev->usb_active))
+ 		return -EPERM;
+ 
+ 	urb = dlfb_get_urb(dev);
+ 	if (!urb)
+ 		return -ENOMEM;
+ 
+ 	buf = (char *) urb->transfer_buffer;
+ 
+ 	/*
+ 	* 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 = dlfb_vidreg_lock(buf);
+ 	wrptr = dlfb_set_color_depth(wrptr, 0x00);
+ 	/* set base for 16bpp segment to 0 */
+ 	wrptr = dlfb_set_base16bpp(wrptr, 0);
+ 	/* set base for 8bpp segment to end of fb */
+ 	wrptr = dlfb_set_base8bpp(wrptr, dev->info->fix.smem_len);
+ 
+ 	wrptr = dlfb_set_vid_cmds(wrptr, var);
+ 	wrptr = dlfb_enable_hvsync(wrptr, true);
+ 	wrptr = dlfb_vidreg_unlock(wrptr);
+ 
+ 	writesize = wrptr - buf;
+ 
+ 	retval = dlfb_submit_urb(dev, urb, writesize);
+ 
+ 	return retval;
+ }
+ 
+ static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
+ {
+ 	unsigned long start = vma->vm_start;
+ 	unsigned long size = vma->vm_end - vma->vm_start;
+ 	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+ 	unsigned long page, pos;
+ 
+ 	if (offset + size > info->fix.smem_len)
+ 		return -EINVAL;
+ 
+ 	pos = (unsigned long)info->fix.smem_start + offset;
+ 
+ 	pr_notice("mmap() framebuffer addr:%lu size:%lu\n",
+ 		  pos, size);
+ 
+ 	while (size > 0) {
+ 		page = vmalloc_to_pfn((void *)pos);
+ 		if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
+ 			return -EAGAIN;
+ 
+ 		start += PAGE_SIZE;
+ 		pos += PAGE_SIZE;
+ 		if (size > PAGE_SIZE)
+ 			size -= PAGE_SIZE;
+ 		else
+ 			size = 0;
+ 	}
+ 
+ 	vma->vm_flags |= VM_RESERVED;	/* avoid to swap out this VMA */
+ 	return 0;
+ }
+ 
+ /*
+  * Trims identical data from front and back of line
+  * Sets new front buffer address and width
+  * And returns byte count of identical pixels
+  * Assumes CPU natural alignment (unsigned long)
+  * for back and front buffer ptrs and width
+  */
+ static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
+ {
+ 	int j, k;
+ 	const unsigned long *back = (const unsigned long *) bback;
+ 	const unsigned long *front = (const unsigned long *) *bfront;
+ 	const int width = *width_bytes / sizeof(unsigned long);
+ 	int identical = width;
+ 	int start = width;
+ 	int end = width;
+ 
+ 	prefetch((void *) front);
+ 	prefetch((void *) back);
+ 
+ 	for (j = 0; j < width; j++) {
+ 		if (back[j] != front[j]) {
+ 			start = j;
+ 			break;
+ 		}
+ 	}
+ 
+ 	for (k = width - 1; k > j; k--) {
+ 		if (back[k] != front[k]) {
+ 			end = k+1;
+ 			break;
+ 		}
+ 	}
+ 
+ 	identical = start + (width - end);
+ 	*bfront = (u8 *) &front[start];
+ 	*width_bytes = (end - start) * sizeof(unsigned long);
+ 
+ 	return identical * sizeof(unsigned long);
+ }
+ 
+ /*
+  * Render a command stream for an encoded horizontal line segment of pixels.
+  *
+  * A command buffer holds several commands.
+  * It always begins with a fresh command header
+  * (the protocol doesn't require this, but we enforce it to allow
+  * multiple buffers to be potentially encoded and sent in parallel).
+  * A single command encodes one contiguous horizontal line of pixels
+  *
+  * The function relies on the client to do all allocation, so that
+  * rendering can be done directly to output buffers (e.g. USB URBs).
+  * The function fills the supplied command buffer, providing information
+  * on where it left off, so the client may call in again with additional
+  * buffers if the line will take several buffers to complete.
+  *
+  * A single command can transmit a maximum of 256 pixels,
+  * regardless of the compression ratio (protocol design limit).
+  * To the hardware, 0 for a size byte means 256
+  *
+  * Rather than 256 pixel commands which are either rl or raw encoded,
+  * the rlx command simply assumes alternating raw and rl spans within one cmd.
+  * This has a slightly larger header overhead, but produces more even results.
+  * It also processes all data (read and write) in a single pass.
+  * Performance benchmarks of common cases show it having just slightly better
+  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
+  * But for very rl friendly data, will compress not quite as well.
+  */
+ static void dlfb_compress_hline(
+ 	const uint16_t **pixel_start_ptr,
+ 	const uint16_t *const pixel_end,
+ 	uint32_t *device_address_ptr,
+ 	uint8_t **command_buffer_ptr,
+ 	const uint8_t *const cmd_buffer_end)
+ {
+ 	const uint16_t *pixel = *pixel_start_ptr;
+ 	uint32_t dev_addr  = *device_address_ptr;
+ 	uint8_t *cmd = *command_buffer_ptr;
+ 	const int bpp = 2;
+ 
+ 	while ((pixel_end > pixel) &&
+ 	       (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
+ 		uint8_t *raw_pixels_count_byte = 0;
+ 		uint8_t *cmd_pixels_count_byte = 0;
+ 		const uint16_t *raw_pixel_start = 0;
+ 		const uint16_t *cmd_pixel_start, *cmd_pixel_end = 0;
+ 
+ 		prefetchw((void *) cmd); /* pull in one cache line at least */
+ 
+ 		*cmd++ = 0xAF;
+ 		*cmd++ = 0x6B;
+ 		*cmd++ = (uint8_t) ((dev_addr >> 16) & 0xFF);
+ 		*cmd++ = (uint8_t) ((dev_addr >> 8) & 0xFF);
+ 		*cmd++ = (uint8_t) ((dev_addr) & 0xFF);
+ 
+ 		cmd_pixels_count_byte = cmd++; /*  we'll know this later */
+ 		cmd_pixel_start = pixel;
+ 
+ 		raw_pixels_count_byte = cmd++; /*  we'll know this later */
+ 		raw_pixel_start = pixel;
+ 
+ 		cmd_pixel_end = pixel + min(MAX_CMD_PIXELS + 1,
+ 			min((int)(pixel_end - pixel),
+ 			    (int)(cmd_buffer_end - cmd) / bpp));
+ 
+ 		prefetch_range((void *) pixel, (cmd_pixel_end - pixel) * bpp);
+ 
+ 		while (pixel < cmd_pixel_end) {
+ 			const uint16_t * const repeating_pixel = pixel;
+ 
+ 			*(uint16_t *)cmd = cpu_to_be16p(pixel);
+ 			cmd += 2;
+ 			pixel++;
+ 
+ 			if (unlikely((pixel < cmd_pixel_end) &&
+ 				     (*pixel == *repeating_pixel))) {
+ 				/* go back and fill in raw pixel count */
+ 				*raw_pixels_count_byte = ((repeating_pixel -
+ 						raw_pixel_start) + 1) & 0xFF;
+ 
+ 				while ((pixel < cmd_pixel_end)
+ 				       && (*pixel == *repeating_pixel)) {
+ 					pixel++;
+ 				}
+ 
+ 				/* immediately after raw data is repeat byte */
+ 				*cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
+ 
+ 				/* Then start another raw pixel span */
+ 				raw_pixel_start = pixel;
+ 				raw_pixels_count_byte = cmd++;
+ 			}
+ 		}
+ 
+ 		if (pixel > raw_pixel_start) {
+ 			/* finalize last RAW span */
+ 			*raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
+ 		}
+ 
+ 		*cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
+ 		dev_addr += (pixel - cmd_pixel_start) * bpp;
+ 	}
+ 
+ 	if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
+ 		/* Fill leftover bytes with no-ops */
+ 		if (cmd_buffer_end > cmd)
+ 			memset(cmd, 0xAF, cmd_buffer_end - cmd);
+ 		cmd = (uint8_t *) cmd_buffer_end;
+ 	}
+ 
+ 	*command_buffer_ptr = cmd;
+ 	*pixel_start_ptr = pixel;
+ 	*device_address_ptr = dev_addr;
+ 
+ 	return;
+ }
+ 
+ /*
+  * There are 3 copies of every pixel: The front buffer that the fbdev
+  * client renders to, the actual framebuffer across the USB bus in hardware
+  * (that we can only write to, slowly, and can never read), and (optionally)
+  * our shadow copy that tracks what's been sent to that hardware buffer.
+  */
+ static int dlfb_render_hline(struct dlfb_data *dev, struct urb **urb_ptr,
+ 			      const char *front, char **urb_buf_ptr,
+ 			      u32 byte_offset, u32 byte_width,
+ 			      int *ident_ptr, int *sent_ptr)
+ {
+ 	const u8 *line_start, *line_end, *next_pixel;
+ 	u32 dev_addr = dev->base16 + byte_offset;
+ 	struct urb *urb = *urb_ptr;
+ 	u8 *cmd = *urb_buf_ptr;
+ 	u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
+ 
+ 	line_start = (u8 *) (front + byte_offset);
+ 	next_pixel = line_start;
+ 	line_end = next_pixel + byte_width;
+ 
+ 	if (dev->backing_buffer) {
+ 		int offset;
+ 		const u8 *back_start = (u8 *) (dev->backing_buffer
+ 						+ byte_offset);
+ 
+ 		*ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
+ 			&byte_width);
+ 
+ 		offset = next_pixel - line_start;
+ 		line_end = next_pixel + byte_width;
+ 		dev_addr += offset;
+ 		back_start += offset;
+ 		line_start += offset;
+ 
+ 		memcpy((char *)back_start, (char *) line_start,
+ 		       byte_width);
+ 	}
+ 
+ 	while (next_pixel < line_end) {
+ 
+ 		dlfb_compress_hline((const uint16_t **) &next_pixel,
+ 			     (const uint16_t *) line_end, &dev_addr,
+ 			(u8 **) &cmd, (u8 *) cmd_end);
+ 
+ 		if (cmd >= cmd_end) {
+ 			int len = cmd - (u8 *) urb->transfer_buffer;
+ 			if (dlfb_submit_urb(dev, urb, len))
+ 				return 1; /* lost pixels is set */
+ 			*sent_ptr += len;
+ 			urb = dlfb_get_urb(dev);
+ 			if (!urb)
+ 				return 1; /* lost_pixels is set */
+ 			*urb_ptr = urb;
+ 			cmd = urb->transfer_buffer;
+ 			cmd_end = &cmd[urb->transfer_buffer_length];
+ 		}
+ 	}
+ 
+ 	*urb_buf_ptr = cmd;
+ 
+ 	return 0;
+ }
+ 
+ int dlfb_handle_damage(struct dlfb_data *dev, int x, int y,
+ 	       int width, int height, char *data)
+ {
+ 	int i, ret;
+ 	char *cmd;
+ 	cycles_t start_cycles, end_cycles;
+ 	int bytes_sent = 0;
+ 	int bytes_identical = 0;
+ 	struct urb *urb;
+ 	int aligned_x;
+ 
+ 	start_cycles = get_cycles();
+ 
+ 	aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
+ 	width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
+ 	x = aligned_x;
+ 
+ 	if ((width <= 0) ||
+ 	    (x + width > dev->info->var.xres) ||
+ 	    (y + height > dev->info->var.yres))
+ 		return -EINVAL;
+ 
+ 	if (!atomic_read(&dev->usb_active))
+ 		return 0;
+ 
+ 	urb = dlfb_get_urb(dev);
+ 	if (!urb)
+ 		return 0;
+ 	cmd = urb->transfer_buffer;
+ 
+ 	for (i = y; i < y + height ; i++) {
+ 		const int line_offset = dev->info->fix.line_length * i;
+ 		const int byte_offset = line_offset + (x * BPP);
+ 
+ 		if (dlfb_render_hline(dev, &urb,
+ 				      (char *) dev->info->fix.smem_start,
+ 				      &cmd, byte_offset, width * BPP,
+ 				      &bytes_identical, &bytes_sent))
+ 			goto error;
+ 	}
+ 
+ 	if (cmd > (char *) urb->transfer_buffer) {
+ 		/* Send partial buffer remaining before exiting */
+ 		int len = cmd - (char *) urb->transfer_buffer;
+ 		ret = dlfb_submit_urb(dev, urb, len);
+ 		bytes_sent += len;
+ 	} else
+ 		dlfb_urb_completion(urb);
+ 
+ error:
+ 	atomic_add(bytes_sent, &dev->bytes_sent);
+ 	atomic_add(bytes_identical, &dev->bytes_identical);
+ 	atomic_add(width*height*2, &dev->bytes_rendered);
+ 	end_cycles = get_cycles();
+ 	atomic_add(((unsigned int) ((end_cycles - start_cycles)
+ 		    >> 10)), /* Kcycles */
+ 		   &dev->cpu_kcycles_used);
+ 
+ 	return 0;
+ }
+ 
+ /*
+  * Path triggered by usermode clients who write to filesystem
+  * e.g. cat filename > /dev/fb1
+  * Not used by X Windows or text-mode console. But useful for testing.
+  * Slow because of extra copy and we must assume all pixels dirty.
+  */
+ static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
+ 			  size_t count, loff_t *ppos)
+ {
+ 	ssize_t result;
+ 	struct dlfb_data *dev = info->par;
+ 	u32 offset = (u32) *ppos;
+ 
+ 	result = fb_sys_write(info, buf, count, ppos);
+ 
+ 	if (result > 0) {
+ 		int start = max((int)(offset / info->fix.line_length) - 1, 0);
+ 		int lines = min((u32)((result / info->fix.line_length) + 1),
+ 				(u32)info->var.yres);
+ 
+ 		dlfb_handle_damage(dev, 0, start, info->var.xres,
+ 			lines, info->screen_base);
+ 	}
+ 
+ 	return result;
+ }
+ 
+ /* hardware has native COPY command (see libdlo), but not worth it for fbcon */
+ static void dlfb_ops_copyarea(struct fb_info *info,
+ 				const struct fb_copyarea *area)
+ {
+ 
+ 	struct dlfb_data *dev = info->par;
+ 
+ 	sys_copyarea(info, area);
+ 
+ 	dlfb_handle_damage(dev, area->dx, area->dy,
+ 			area->width, area->height, info->screen_base);
+ }
+ 
+ static void dlfb_ops_imageblit(struct fb_info *info,
+ 				const struct fb_image *image)
+ {
+ 	struct dlfb_data *dev = info->par;
+ 
+ 	sys_imageblit(info, image);
+ 
+ 	dlfb_handle_damage(dev, image->dx, image->dy,
+ 			image->width, image->height, info->screen_base);
+ }
+ 
+ static void dlfb_ops_fillrect(struct fb_info *info,
+ 			  const struct fb_fillrect *rect)
+ {
+ 	struct dlfb_data *dev = info->par;
+ 
+ 	sys_fillrect(info, rect);
+ 
+ 	dlfb_handle_damage(dev, rect->dx, rect->dy, rect->width,
+ 			      rect->height, info->screen_base);
+ }
+ 
+ /*
+  * NOTE: fb_defio.c is holding info->fbdefio.mutex
+  *   Touching ANY framebuffer memory that triggers a page fault
+  *   in fb_defio will cause a deadlock, when it also tries to
+  *   grab the same mutex.
+  */
+ static void dlfb_dpy_deferred_io(struct fb_info *info,
+ 				struct list_head *pagelist)
+ {
+ 	struct page *cur;
+ 	struct fb_deferred_io *fbdefio = info->fbdefio;
+ 	struct dlfb_data *dev = info->par;
+ 	struct urb *urb;
+ 	char *cmd;
+ 	cycles_t start_cycles, end_cycles;
+ 	int bytes_sent = 0;
+ 	int bytes_identical = 0;
+ 	int bytes_rendered = 0;
+ 
+ 	if (!fb_defio)
+ 		return;
+ 
+ 	if (!atomic_read(&dev->usb_active))
+ 		return;
+ 
+ 	start_cycles = get_cycles();
+ 
+ 	urb = dlfb_get_urb(dev);
+ 	if (!urb)
+ 		return;
+ 
+ 	cmd = urb->transfer_buffer;
+ 
+ 	/* walk the written page list and render each to device */
+ 	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
+ 
+ 		if (dlfb_render_hline(dev, &urb, (char *) info->fix.smem_start,
+ 				  &cmd, cur->index << PAGE_SHIFT,
+ 				  PAGE_SIZE, &bytes_identical, &bytes_sent))
+ 			goto error;
+ 		bytes_rendered += PAGE_SIZE;
+ 	}
+ 
+ 	if (cmd > (char *) urb->transfer_buffer) {
+ 		/* Send partial buffer remaining before exiting */
+ 		int len = cmd - (char *) urb->transfer_buffer;
+ 		dlfb_submit_urb(dev, urb, len);
+ 		bytes_sent += len;
+ 	} else
+ 		dlfb_urb_completion(urb);
+ 
+ error:
+ 	atomic_add(bytes_sent, &dev->bytes_sent);
+ 	atomic_add(bytes_identical, &dev->bytes_identical);
+ 	atomic_add(bytes_rendered, &dev->bytes_rendered);
+ 	end_cycles = get_cycles();
+ 	atomic_add(((unsigned int) ((end_cycles - start_cycles)
+ 		    >> 10)), /* Kcycles */
+ 		   &dev->cpu_kcycles_used);
+ }
+ 
+ static int dlfb_get_edid(struct dlfb_data *dev, char *edid, int len)
+ {
+ 	int i;
+ 	int ret;
+ 	char *rbuf;
+ 
+ 	rbuf = kmalloc(2, GFP_KERNEL);
+ 	if (!rbuf)
+ 		return 0;
+ 
+ 	for (i = 0; i < len; i++) {
+ 		ret = usb_control_msg(dev->udev,
+ 				    usb_rcvctrlpipe(dev->udev, 0), (0x02),
+ 				    (0x80 | (0x02 << 5)), i << 8, 0xA1, rbuf, 2,
+ 				    HZ);
+ 		if (ret < 1) {
+ 			pr_err("Read EDID byte %d failed err %x\n", i, ret);
+ 			i--;
+ 			break;
+ 		}
+ 		edid[i] = rbuf[1];
+ 	}
+ 
+ 	kfree(rbuf);
+ 
+ 	return i;
+ }
+ 
+ static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
+ 				unsigned long arg)
+ {
+ 
+ 	struct dlfb_data *dev = info->par;
+ 	struct dloarea *area = NULL;
+ 
+ 	if (!atomic_read(&dev->usb_active))
+ 		return 0;
+ 
+ 	/* TODO: Update X server to get this from sysfs instead */
+ 	if (cmd == DLFB_IOCTL_RETURN_EDID) {
+ 		char *edid = (char *)arg;
+ 		if (copy_to_user(edid, dev->edid, dev->edid_size))
+ 			return -EFAULT;
+ 		return 0;
+ 	}
+ 
+ 	/* TODO: Help propose a standard fb.h ioctl to report mmap damage */
+ 	if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
+ 
+ 		/*
+ 		 * If we have a damage-aware client, turn fb_defio "off"
+ 		 * To avoid perf imact of unecessary page fault handling.
+ 		 * Done by resetting the delay for this fb_info to a very
+ 		 * long period. Pages will become writable and stay that way.
+ 		 * Reset to normal value when all clients have closed this fb.
+ 		 */
+ 		if (info->fbdefio)
+ 			info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
+ 
+ 		area = (struct dloarea *)arg;
+ 
+ 		if (area->x < 0)
+ 			area->x = 0;
+ 
+ 		if (area->x > info->var.xres)
+ 			area->x = info->var.xres;
+ 
+ 		if (area->y < 0)
+ 			area->y = 0;
+ 
+ 		if (area->y > info->var.yres)
+ 			area->y = info->var.yres;
+ 
+ 		dlfb_handle_damage(dev, area->x, area->y, area->w, area->h,
+ 			   info->screen_base);
+ 	}
+ 
+ 	return 0;
+ }
+ 
+ /* taken from vesafb */
+ static int
+ dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
+ 	       unsigned blue, unsigned transp, struct fb_info *info)
+ {
+ 	int err = 0;
+ 
+ 	if (regno >= info->cmap.len)
+ 		return 1;
+ 
+ 	if (regno < 16) {
+ 		if (info->var.red.offset == 10) {
+ 			/* 1:5:5:5 */
+ 			((u32 *) (info->pseudo_palette))[regno] =
+ 			    ((red & 0xf800) >> 1) |
+ 			    ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
+ 		} else {
+ 			/* 0:5:6:5 */
+ 			((u32 *) (info->pseudo_palette))[regno] =
+ 			    ((red & 0xf800)) |
+ 			    ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
+ 		}
+ 	}
+ 
+ 	return err;
+ }
+ 
+ /*
+  * It's common for several clients to have framebuffer open simultaneously.
+  * e.g. both fbcon and X. Makes things interesting.
+  * Assumes caller is holding info->lock (for open and release at least)
+  */
+ static int dlfb_ops_open(struct fb_info *info, int user)
+ {
+ 	struct dlfb_data *dev = info->par;
+ 
+ 	/*
+ 	 * fbcon aggressively connects to first framebuffer it finds,
+ 	 * preventing other clients (X) from working properly. Usually
+ 	 * not what the user wants. Fail by default with option to enable.
+ 	 */
+ 	if ((user == 0) & (!console))
+ 		return -EBUSY;
+ 
+ 	/* If the USB device is gone, we don't accept new opens */
+ 	if (dev->virtualized)
+ 		return -ENODEV;
+ 
+ 	dev->fb_count++;
+ 
+ 	kref_get(&dev->kref);
+ 
+ 	if (fb_defio && (info->fbdefio == NULL)) {
+ 		/* enable defio at last moment if not disabled by client */
+ 
+ 		struct fb_deferred_io *fbdefio;
+ 
+ 		fbdefio = kmalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
+ 
+ 		if (fbdefio) {
+ 			fbdefio->delay = DL_DEFIO_WRITE_DELAY;
+ 			fbdefio->deferred_io = dlfb_dpy_deferred_io;
+ 		}
+ 
+ 		info->fbdefio = fbdefio;
+ 		fb_deferred_io_init(info);
+ 	}
+ 
+ 	pr_notice("open /dev/fb%d user=%d fb_info=%p count=%d\n",
+ 	    info->node, user, info, dev->fb_count);
+ 
+ 	return 0;
+ }
+ 
+ /*
+  * Called when all client interfaces to start transactions have been disabled,
+  * and all references to our device instance (dlfb_data) are released.
+  * Every transaction must have a reference, so we know are fully spun down
+  */
+ static void dlfb_free(struct kref *kref)
+ {
+ 	struct dlfb_data *dev = container_of(kref, struct dlfb_data, kref);
+ 
+ 	/* this function will wait for all in-flight urbs to complete */
+ 	if (dev->urbs.count > 0)
+ 		dlfb_free_urb_list(dev);
+ 
+ 	if (dev->backing_buffer)
+ 		vfree(dev->backing_buffer);
+ 
+ 	kfree(dev->edid);
+ 
+ 	pr_warn("freeing dlfb_data %p\n", dev);
+ 
+ 	kfree(dev);
+ }
+ 
+ static void dlfb_release_urb_work(struct work_struct *work)
+ {
+ 	struct urb_node *unode = container_of(work, struct urb_node,
+ 					      release_urb_work.work);
+ 
+ 	up(&unode->dev->urbs.limit_sem);
+ }
+ 
+ static void dlfb_free_framebuffer_work(struct work_struct *work)
+ {
+ 	struct dlfb_data *dev = container_of(work, struct dlfb_data,
+ 					     free_framebuffer_work.work);
+ 	struct fb_info *info = dev->info;
+ 	int node = info->node;
+ 
+ 	unregister_framebuffer(info);
+ 
+ 	if (info->cmap.len != 0)
+ 		fb_dealloc_cmap(&info->cmap);
+ 	if (info->monspecs.modedb)
+ 		fb_destroy_modedb(info->monspecs.modedb);
+ 	if (info->screen_base)
+ 		vfree(info->screen_base);
+ 
+ 	fb_destroy_modelist(&info->modelist);
+ 
+ 	dev->info = 0;
+ 
+ 	/* Assume info structure is freed after this point */
+ 	framebuffer_release(info);
+ 
+ 	pr_warn("fb_info for /dev/fb%d has been freed\n", node);
+ 
+ 	/* ref taken in probe() as part of registering framebfufer */
+ 	kref_put(&dev->kref, dlfb_free);
+ }
+ 
+ /*
+  * Assumes caller is holding info->lock mutex (for open and release at least)
+  */
+ static int dlfb_ops_release(struct fb_info *info, int user)
+ {
+ 	struct dlfb_data *dev = info->par;
+ 
+ 	dev->fb_count--;
+ 
+ 	/* We can't free fb_info here - fbmem will touch it when we return */
+ 	if (dev->virtualized && (dev->fb_count == 0))
+ 		schedule_delayed_work(&dev->free_framebuffer_work, HZ);
+ 
+ 	if ((dev->fb_count == 0) && (info->fbdefio)) {
+ 		fb_deferred_io_cleanup(info);
+ 		kfree(info->fbdefio);
+ 		info->fbdefio = NULL;
+ 		info->fbops->fb_mmap = dlfb_ops_mmap;
+ 	}
+ 
+ 	pr_warn("released /dev/fb%d user=%d count=%d\n",
+ 		  info->node, user, dev->fb_count);
+ 
+ 	kref_put(&dev->kref, dlfb_free);
+ 
+ 	return 0;
+ }
+ 
+ /*
+  * Check whether a video mode is supported by the DisplayLink chip
+  * We start from monitor's modes, so don't need to filter that here
+  */
+ static int dlfb_is_valid_mode(struct fb_videomode *mode,
+ 		struct fb_info *info)
+ {
+ 	struct dlfb_data *dev = info->par;
+ 
+ 	if (mode->xres * mode->yres > dev->sku_pixel_limit) {
+ 		pr_warn("%dx%d beyond chip capabilities\n",
+ 		       mode->xres, mode->yres);
+ 		return 0;
+ 	}
+ 
+ 	pr_info("%dx%d valid mode\n", mode->xres, mode->yres);
+ 
+ 	return 1;
+ }
+ 
+ static void dlfb_var_color_format(struct fb_var_screeninfo *var)
+ {
+ 	const struct fb_bitfield red = { 11, 5, 0 };
+ 	const struct fb_bitfield green = { 5, 6, 0 };
+ 	const struct fb_bitfield blue = { 0, 5, 0 };
+ 
+ 	var->bits_per_pixel = 16;
+ 	var->red = red;
+ 	var->green = green;
+ 	var->blue = blue;
+ }
+ 
+ static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
+ 				struct fb_info *info)
+ {
+ 	struct fb_videomode mode;
+ 
+ 	/* TODO: support dynamically changing framebuffer size */
+ 	if ((var->xres * var->yres * 2) > info->fix.smem_len)
+ 		return -EINVAL;
+ 
+ 	/* set device-specific elements of var unrelated to mode */
+ 	dlfb_var_color_format(var);
+ 
+ 	fb_var_to_videomode(&mode, var);
+ 
+ 	if (!dlfb_is_valid_mode(&mode, info))
+ 		return -EINVAL;
+ 
+ 	return 0;
+ }
+ 
+ static int dlfb_ops_set_par(struct fb_info *info)
+ {
+ 	struct dlfb_data *dev = info->par;
+ 	int result;
+ 	u16 *pix_framebuffer;
+ 	int i;
+ 
+ 	pr_notice("set_par mode %dx%d\n", info->var.xres, info->var.yres);
+ 
+ 	result = dlfb_set_video_mode(dev, &info->var);
+ 
+ 	if ((result == 0) && (dev->fb_count == 0)) {
+ 
+ 		/* paint greenscreen */
+ 
+ 		pix_framebuffer = (u16 *) info->screen_base;
+ 		for (i = 0; i < info->fix.smem_len / 2; i++)
+ 			pix_framebuffer[i] = 0x37e6;
+ 
+ 		dlfb_handle_damage(dev, 0, 0, info->var.xres, info->var.yres,
+ 				   info->screen_base);
+ 	}
+ 
+ 	return result;
+ }
+ 
+ /*
+  * In order to come back from full DPMS off, we need to set the mode again
+  */
+ static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
+ {
+ 	struct dlfb_data *dev = info->par;
+ 
+ 	if (blank_mode != FB_BLANK_UNBLANK) {
+ 		char *bufptr;
+ 		struct urb *urb;
+ 
+ 		urb = dlfb_get_urb(dev);
+ 		if (!urb)
+ 			return 0;
+ 
+ 		bufptr = (char *) urb->transfer_buffer;
+ 		bufptr = dlfb_vidreg_lock(bufptr);
+ 		bufptr = dlfb_enable_hvsync(bufptr, false);
+ 		bufptr = dlfb_vidreg_unlock(bufptr);
+ 
+ 		dlfb_submit_urb(dev, urb, bufptr -
+ 				(char *) urb->transfer_buffer);
+ 	} else {
+ 		dlfb_set_video_mode(dev, &info->var);
+ 	}
+ 
+ 	return 0;
+ }
+ 
+ static struct fb_ops dlfb_ops = {
+ 	.owner = THIS_MODULE,
+ 	.fb_read = fb_sys_read,
+ 	.fb_write = dlfb_ops_write,
+ 	.fb_setcolreg = dlfb_ops_setcolreg,
+ 	.fb_fillrect = dlfb_ops_fillrect,
+ 	.fb_copyarea = dlfb_ops_copyarea,
+ 	.fb_imageblit = dlfb_ops_imageblit,
+ 	.fb_mmap = dlfb_ops_mmap,
+ 	.fb_ioctl = dlfb_ops_ioctl,
+ 	.fb_open = dlfb_ops_open,
+ 	.fb_release = dlfb_ops_release,
+ 	.fb_blank = dlfb_ops_blank,
+ 	.fb_check_var = dlfb_ops_check_var,
+ 	.fb_set_par = dlfb_ops_set_par,
+ };
+ 
+ 
+ /*
+  * Assumes &info->lock held by caller
+  * Assumes no active clients have framebuffer open
+  */
+ static int dlfb_realloc_framebuffer(struct dlfb_data *dev, struct fb_info *info)
+ {
+ 	int retval = -ENOMEM;
+ 	int old_len = info->fix.smem_len;
+ 	int new_len;
+ 	unsigned char *old_fb = info->screen_base;
+ 	unsigned char *new_fb;
+ 	unsigned char *new_back;
+ 
+ 	pr_warn("Reallocating framebuffer. Addresses will change!\n");
+ 
+ 	new_len = info->fix.line_length * info->var.yres;
+ 
+ 	if (PAGE_ALIGN(new_len) > old_len) {
+ 		/*
+ 		 * Alloc system memory for virtual framebuffer
+ 		 */
+ 		new_fb = vmalloc(new_len);
+ 		if (!new_fb) {
+ 			pr_err("Virtual framebuffer alloc failed\n");
+ 			goto error;
+ 		}
+ 
+ 		if (info->screen_base) {
+ 			memcpy(new_fb, old_fb, old_len);
+ 			vfree(info->screen_base);
+ 		}
+ 
+ 		info->screen_base = new_fb;
+ 		info->fix.smem_len = PAGE_ALIGN(new_len);
+ 		info->fix.smem_start = (unsigned long) new_fb;
+ 		info->flags = udlfb_info_flags;
+ 
+ 		/*
+ 		 * Second framebuffer copy to mirror the framebuffer state
+ 		 * on the physical USB device. We can function without this.
+ 		 * But with imperfect damage info we may send pixels over USB
+ 		 * that were, in fact, unchanged - wasting limited USB bandwidth
+ 		 */
+ 		new_back = vmalloc(new_len);
+ 		if (!new_back)
+ 			pr_info("No shadow/backing buffer allcoated\n");
+ 		else {
+ 			if (dev->backing_buffer)
+ 				vfree(dev->backing_buffer);
+ 			dev->backing_buffer = new_back;
+ 			memset(dev->backing_buffer, 0, new_len);
+ 		}
+ 	}
+ 
+ 	retval = 0;
+ 
+ error:
+ 	return retval;
+ }
+ 
+ /*
+  * 1) Get EDID from hw, or use sw default
+  * 2) Parse into various fb_info structs
+  * 3) Allocate virtual framebuffer memory to back highest res mode
+  *
+  * Parses EDID into three places used by various parts of fbdev:
+  * fb_var_screeninfo contains the timing of the monitor's preferred mode
+  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
+  * fb_info.modelist is a linked list of all monitor & VESA modes which work
+  *
+  * If EDID is not readable/valid, then modelist is all VESA modes,
+  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
+  * Returns 0 if successful
+  */
+ static int dlfb_setup_modes(struct dlfb_data *dev,
+ 			   struct fb_info *info,
+ 			   char *default_edid, size_t default_edid_size)
+ {
+ 	int i;
+ 	const struct fb_videomode *default_vmode = NULL;
+ 	int result = 0;
+ 	char *edid;
+ 	int tries = 3;
+ 
+ 	if (info->dev) /* only use mutex if info has been registered */
+ 		mutex_lock(&info->lock);
+ 
+ 	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
+ 	if (!edid) {
+ 		result = -ENOMEM;
+ 		goto error;
+ 	}
+ 
+ 	fb_destroy_modelist(&info->modelist);
+ 	memset(&info->monspecs, 0, sizeof(info->monspecs));
+ 
+ 	/*
+ 	 * Try to (re)read EDID from hardware first
+ 	 * EDID data may return, but not parse as valid
+ 	 * Try again a few times, in case of e.g. analog cable noise
+ 	 */
+ 	while (tries--) {
+ 
+ 		i = dlfb_get_edid(dev, edid, EDID_LENGTH);
+ 
+ 		if (i >= EDID_LENGTH)
+ 			fb_edid_to_monspecs(edid, &info->monspecs);
+ 
+ 		if (info->monspecs.modedb_len > 0) {
+ 			dev->edid = edid;
+ 			dev->edid_size = i;
+ 			break;
+ 		}
+ 	}
+ 
+ 	/* If that fails, use a previously returned EDID if available */
+ 	if (info->monspecs.modedb_len == 0) {
+ 
+ 		pr_err("Unable to get valid EDID from device/display\n");
+ 
+ 		if (dev->edid) {
+ 			fb_edid_to_monspecs(dev->edid, &info->monspecs);
+ 			if (info->monspecs.modedb_len > 0)
+ 				pr_err("Using previously queried EDID\n");
+ 		}
+ 	}
+ 
+ 	/* If that fails, use the default EDID we were handed */
+ 	if (info->monspecs.modedb_len == 0) {
+ 		if (default_edid_size >= EDID_LENGTH) {
+ 			fb_edid_to_monspecs(default_edid, &info->monspecs);
+ 			if (info->monspecs.modedb_len > 0) {
+ 				memcpy(edid, default_edid, default_edid_size);
+ 				dev->edid = edid;
+ 				dev->edid_size = default_edid_size;
+ 				pr_err("Using default/backup EDID\n");
+ 			}
+ 		}
+ 	}
+ 
+ 	/* If we've got modes, let's pick a best default mode */
+ 	if (info->monspecs.modedb_len > 0) {
+ 
+ 		for (i = 0; i < info->monspecs.modedb_len; i++) {
+ 			if (dlfb_is_valid_mode(&info->monspecs.modedb[i], info))
+ 				fb_add_videomode(&info->monspecs.modedb[i],
+ 					&info->modelist);
+ 			else /* if we've removed top/best mode */
+ 				info->monspecs.misc &= ~FB_MISC_1ST_DETAIL;
+ 		}
+ 
+ 		default_vmode = fb_find_best_display(&info->monspecs,
+ 						     &info->modelist);
+ 	}
+ 
+ 	/* If everything else has failed, fall back to safe default mode */
+ 	if (default_vmode == NULL) {
+ 
+ 		struct fb_videomode fb_vmode = {0};
+ 
+ 		/*
+ 		 * Add the standard VESA modes to our modelist
+ 		 * Since we don't have EDID, there may be modes that
+ 		 * overspec monitor and/or are incorrect aspect ratio, etc.
+ 		 * But at least the user has a chance to choose
+ 		 */
+ 		for (i = 0; i < VESA_MODEDB_SIZE; i++) {
+ 			if (dlfb_is_valid_mode((struct fb_videomode *)
+ 						&vesa_modes[i], info))
+ 				fb_add_videomode(&vesa_modes[i],
+ 						 &info->modelist);
+ 		}
+ 
+ 		/*
+ 		 * default to resolution safe for projectors
+ 		 * (since they are most common case without EDID)
+ 		 */
+ 		fb_vmode.xres = 800;
+ 		fb_vmode.yres = 600;
+ 		fb_vmode.refresh = 60;
+ 		default_vmode = fb_find_nearest_mode(&fb_vmode,
+ 						     &info->modelist);
+ 	}
+ 
+ 	/* If we have good mode and no active clients*/
+ 	if ((default_vmode != NULL) && (dev->fb_count == 0)) {
+ 
+ 		fb_videomode_to_var(&info->var, default_vmode);
+ 		dlfb_var_color_format(&info->var);
+ 
+ 		/*
+ 		 * with mode size info, we can now alloc our framebuffer.
+ 		 */
+ 		memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
+ 		info->fix.line_length = info->var.xres *
+ 			(info->var.bits_per_pixel / 8);
+ 
+ 		result = dlfb_realloc_framebuffer(dev, info);
+ 
+ 	} else
+ 		result = -EINVAL;
+ 
+ error:
+ 	if (edid && (dev->edid != edid))
+ 		kfree(edid);
+ 
+ 	if (info->dev)
+ 		mutex_unlock(&info->lock);
+ 
+ 	return result;
+ }
+ 
+ static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
+ 				   struct device_attribute *a, char *buf) {
+ 	struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ 	struct dlfb_data *dev = fb_info->par;
+ 	return snprintf(buf, PAGE_SIZE, "%u\n",
+ 			atomic_read(&dev->bytes_rendered));
+ }
+ 
+ static ssize_t metrics_bytes_identical_show(struct device *fbdev,
+ 				   struct device_attribute *a, char *buf) {
+ 	struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ 	struct dlfb_data *dev = fb_info->par;
+ 	return snprintf(buf, PAGE_SIZE, "%u\n",
+ 			atomic_read(&dev->bytes_identical));
+ }
+ 
+ static ssize_t metrics_bytes_sent_show(struct device *fbdev,
+ 				   struct device_attribute *a, char *buf) {
+ 	struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ 	struct dlfb_data *dev = fb_info->par;
+ 	return snprintf(buf, PAGE_SIZE, "%u\n",
+ 			atomic_read(&dev->bytes_sent));
+ }
+ 
+ static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
+ 				   struct device_attribute *a, char *buf) {
+ 	struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ 	struct dlfb_data *dev = fb_info->par;
+ 	return snprintf(buf, PAGE_SIZE, "%u\n",
+ 			atomic_read(&dev->cpu_kcycles_used));
+ }
+ 
+ static ssize_t edid_show(
+ 			struct file *filp,
+ 			struct kobject *kobj, struct bin_attribute *a,
+ 			 char *buf, loff_t off, size_t count) {
+ 	struct device *fbdev = container_of(kobj, struct device, kobj);
+ 	struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ 	struct dlfb_data *dev = fb_info->par;
+ 
+ 	if (dev->edid == NULL)
+ 		return 0;
+ 
+ 	if ((off >= dev->edid_size) || (count > dev->edid_size))
+ 		return 0;
+ 
+ 	if (off + count > dev->edid_size)
+ 		count = dev->edid_size - off;
+ 
+ 	pr_info("sysfs edid copy %p to %p, %d bytes\n",
+ 		dev->edid, buf, (int) count);
+ 
+ 	memcpy(buf, dev->edid, count);
+ 
+ 	return count;
+ }
+ 
+ static ssize_t edid_store(
+ 			struct file *filp,
+ 			struct kobject *kobj, struct bin_attribute *a,
+ 			char *src, loff_t src_off, size_t src_size) {
+ 	struct device *fbdev = container_of(kobj, struct device, kobj);
+ 	struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ 	struct dlfb_data *dev = fb_info->par;
+ 
+ 	/* We only support write of entire EDID at once, no offset*/
+ 	if ((src_size != EDID_LENGTH) || (src_off != 0))
+ 		return 0;
+ 
+ 	dlfb_setup_modes(dev, fb_info, src, src_size);
+ 
+ 	if (dev->edid && (memcmp(src, dev->edid, src_size) == 0)) {
+ 		pr_info("sysfs written EDID is new default\n");
+ 		dlfb_ops_set_par(fb_info);
+ 		return src_size;
+ 	} else
+ 		return 0;
+ }
+ 
+ static ssize_t metrics_reset_store(struct device *fbdev,
+ 			   struct device_attribute *attr,
+ 			   const char *buf, size_t count)
+ {
+ 	struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ 	struct dlfb_data *dev = fb_info->par;
+ 
+ 	atomic_set(&dev->bytes_rendered, 0);
+ 	atomic_set(&dev->bytes_identical, 0);
+ 	atomic_set(&dev->bytes_sent, 0);
+ 	atomic_set(&dev->cpu_kcycles_used, 0);
+ 
+ 	return count;
+ }
+ 
+ static struct bin_attribute edid_attr = {
+ 	.attr.name = "edid",
+ 	.attr.mode = 0666,
+ 	.size = EDID_LENGTH,
+ 	.read = edid_show,
+ 	.write = edid_store
+ };
+ 
+ static struct device_attribute fb_device_attrs[] = {
+ 	__ATTR_RO(metrics_bytes_rendered),
+ 	__ATTR_RO(metrics_bytes_identical),
+ 	__ATTR_RO(metrics_bytes_sent),
+ 	__ATTR_RO(metrics_cpu_kcycles_used),
 -	__ATTR(metrics_reset, S_IWUGO, NULL, metrics_reset_store),
++	__ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
+ };
+ 
+ /*
+  * 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;
+ }
+ 
+ static int dlfb_parse_vendor_descriptor(struct dlfb_data *dev,
+ 					struct usb_device *usbdev)
+ {
+ 	char *desc;
+ 	char *buf;
+ 	char *desc_end;
+ 
+ 	u8 total_len = 0;
+ 
+ 	buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
+ 	if (!buf)
+ 		return false;
+ 	desc = buf;
+ 
+ 	total_len = usb_get_descriptor(usbdev, 0x5f, /* vendor specific */
+ 				    0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
+ 	if (total_len > 5) {
+ 		pr_info("vendor descriptor length:%x data:%02x %02x %02x %02x" \
+ 			"%02x %02x %02x %02x %02x %02x %02x\n",
+ 			total_len, desc[0],
+ 			desc[1], desc[2], desc[3], desc[4], desc[5], desc[6],
+ 			desc[7], desc[8], desc[9], desc[10]);
+ 
+ 		if ((desc[0] != total_len) || /* descriptor length */
+ 		    (desc[1] != 0x5f) ||   /* vendor descriptor type */
+ 		    (desc[2] != 0x01) ||   /* version (2 bytes) */
+ 		    (desc[3] != 0x00) ||
+ 		    (desc[4] != total_len - 2)) /* length after type */
+ 			goto unrecognized;
+ 
+ 		desc_end = desc + total_len;
+ 		desc += 5; /* the fixed header we've already parsed */
+ 
+ 		while (desc < desc_end) {
+ 			u8 length;
+ 			u16 key;
+ 
+ 			key = *((u16 *) desc);
+ 			desc += sizeof(u16);
+ 			length = *desc;
+ 			desc++;
+ 
+ 			switch (key) {
+ 			case 0x0200: { /* max_area */
+ 				u32 max_area;
+ 				max_area = le32_to_cpu(*((u32 *)desc));
+ 				pr_warn("DL chip limited to %d pixel modes\n",
+ 					max_area);
+ 				dev->sku_pixel_limit = max_area;
+ 				break;
+ 			}
+ 			default:
+ 				break;
+ 			}
+ 			desc += length;
+ 		}
+ 	}
+ 
+ 	goto success;
+ 
+ unrecognized:
+ 	/* allow udlfb to load for now even if firmware unrecognized */
+ 	pr_err("Unrecognized vendor firmware descriptor\n");
+ 
+ success:
+ 	kfree(buf);
+ 	return true;
+ }
+ static int dlfb_usb_probe(struct usb_interface *interface,
+ 			const struct usb_device_id *id)
+ {
+ 	struct usb_device *usbdev;
+ 	struct dlfb_data *dev = 0;
+ 	struct fb_info *info = 0;
+ 	int retval = -ENOMEM;
+ 	int i;
+ 
+ 	/* usb initialization */
+ 
+ 	usbdev = interface_to_usbdev(interface);
+ 
+ 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ 	if (dev == NULL) {
+ 		err("dlfb_usb_probe: failed alloc of dev struct\n");
+ 		goto error;
+ 	}
+ 
+ 	/* we need to wait for both usb and fbdev to spin down on disconnect */
+ 	kref_init(&dev->kref); /* matching kref_put in usb .disconnect fn */
+ 	kref_get(&dev->kref); /* matching kref_put in free_framebuffer_work */
+ 
+ 	dev->udev = usbdev;
+ 	dev->gdev = &usbdev->dev; /* our generic struct device * */
+ 	usb_set_intfdata(interface, dev);
+ 
+ 	pr_info("%s %s - serial #%s\n",
+ 		usbdev->manufacturer, usbdev->product, usbdev->serial);
+ 	pr_info("vid_%04x&pid_%04x&rev_%04x driver's dlfb_data struct at %p\n",
+ 		usbdev->descriptor.idVendor, usbdev->descriptor.idProduct,
+ 		usbdev->descriptor.bcdDevice, dev);
+ 	pr_info("console enable=%d\n", console);
+ 	pr_info("fb_defio enable=%d\n", fb_defio);
+ 
+ 	dev->sku_pixel_limit = 2048 * 1152; /* default to maximum */
+ 
+ 	if (!dlfb_parse_vendor_descriptor(dev, usbdev)) {
+ 		pr_err("firmware not recognized. Assume incompatible device\n");
+ 		goto error;
+ 	}
+ 
+ 	if (!dlfb_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
+ 		retval = -ENOMEM;
+ 		pr_err("dlfb_alloc_urb_list failed\n");
+ 		goto error;
+ 	}
+ 
+ 	/* We don't register a new USB class. Our client interface is fbdev */
+ 
+ 	/* allocates framebuffer driver structure, not framebuffer memory */
+ 	info = framebuffer_alloc(0, &usbdev->dev);
+ 	if (!info) {
+ 		retval = -ENOMEM;
+ 		pr_err("framebuffer_alloc failed\n");
+ 		goto error;
+ 	}
+ 
+ 	dev->info = info;
+ 	info->par = dev;
+ 	info->pseudo_palette = dev->pseudo_palette;
+ 	info->fbops = &dlfb_ops;
+ 
+ 	retval = fb_alloc_cmap(&info->cmap, 256, 0);
+ 	if (retval < 0) {
+ 		pr_err("fb_alloc_cmap failed %x\n", retval);
+ 		goto error;
+ 	}
+ 
+ 	INIT_DELAYED_WORK(&dev->free_framebuffer_work,
+ 			  dlfb_free_framebuffer_work);
+ 
+ 	INIT_LIST_HEAD(&info->modelist);
+ 
+ 	retval = dlfb_setup_modes(dev, info, NULL, 0);
+ 	if (retval != 0) {
+ 		pr_err("unable to find common mode for display and adapter\n");
+ 		goto error;
+ 	}
+ 
+ 	/* ready to begin using device */
+ 
+ 	atomic_set(&dev->usb_active, 1);
+ 	dlfb_select_std_channel(dev);
+ 
+ 	dlfb_ops_check_var(&info->var, info);
+ 	dlfb_ops_set_par(info);
+ 
+ 	retval = register_framebuffer(info);
+ 	if (retval < 0) {
+ 		pr_err("register_framebuffer failed %d\n", retval);
+ 		goto error;
+ 	}
+ 
+ 	for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
+ 		device_create_file(info->dev, &fb_device_attrs[i]);
+ 
+ 	device_create_bin_file(info->dev, &edid_attr);
+ 
+ 	pr_info("DisplayLink USB device /dev/fb%d attached. %dx%d resolution."
+ 			" Using %dK framebuffer memory\n", info->node,
+ 			info->var.xres, info->var.yres,
+ 			((dev->backing_buffer) ?
+ 			info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
+ 	return 0;
+ 
+ error:
+ 	if (dev) {
+ 
+ 		if (info) {
+ 			if (info->cmap.len != 0)
+ 				fb_dealloc_cmap(&info->cmap);
+ 			if (info->monspecs.modedb)
+ 				fb_destroy_modedb(info->monspecs.modedb);
+ 			if (info->screen_base)
+ 				vfree(info->screen_base);
+ 
+ 			fb_destroy_modelist(&info->modelist);
+ 
+ 			framebuffer_release(info);
+ 		}
+ 
+ 		if (dev->backing_buffer)
+ 			vfree(dev->backing_buffer);
+ 
+ 		kref_put(&dev->kref, dlfb_free); /* ref for framebuffer */
+ 		kref_put(&dev->kref, dlfb_free); /* last ref from kref_init */
+ 
+ 		/* dev has been deallocated. Do not dereference */
+ 	}
+ 
+ 	return retval;
+ }
+ 
+ static void dlfb_usb_disconnect(struct usb_interface *interface)
+ {
+ 	struct dlfb_data *dev;
+ 	struct fb_info *info;
+ 	int i;
+ 
+ 	dev = usb_get_intfdata(interface);
+ 	info = dev->info;
+ 
+ 	pr_info("USB disconnect starting\n");
+ 
+ 	/* we virtualize until all fb clients release. Then we free */
+ 	dev->virtualized = true;
+ 
+ 	/* When non-active we'll update virtual framebuffer, but no new urbs */
+ 	atomic_set(&dev->usb_active, 0);
+ 
+ 	/* remove udlfb's sysfs interfaces */
+ 	for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
+ 		device_remove_file(info->dev, &fb_device_attrs[i]);
+ 	device_remove_bin_file(info->dev, &edid_attr);
+ 
+ 	usb_set_intfdata(interface, NULL);
+ 
+ 	/* if clients still have us open, will be freed on last close */
+ 	if (dev->fb_count == 0)
+ 		schedule_delayed_work(&dev->free_framebuffer_work, 0);
+ 
+ 	/* release reference taken by kref_init in probe() */
+ 	kref_put(&dev->kref, dlfb_free);
+ 
+ 	/* consider dlfb_data freed */
+ 
+ 	return;
+ }
+ 
+ static struct usb_driver dlfb_driver = {
+ 	.name = "udlfb",
+ 	.probe = dlfb_usb_probe,
+ 	.disconnect = dlfb_usb_disconnect,
+ 	.id_table = id_table,
+ };
+ 
+ static int __init dlfb_module_init(void)
+ {
+ 	int res;
+ 
+ 	res = usb_register(&dlfb_driver);
+ 	if (res)
+ 		err("usb_register failed. Error number %d", res);
+ 
+ 	return res;
+ }
+ 
+ static void __exit dlfb_module_exit(void)
+ {
+ 	usb_deregister(&dlfb_driver);
+ }
+ 
+ module_init(dlfb_module_init);
+ module_exit(dlfb_module_exit);
+ 
+ static void dlfb_urb_completion(struct urb *urb)
+ {
+ 	struct urb_node *unode = urb->context;
+ 	struct dlfb_data *dev = unode->dev;
+ 	unsigned long flags;
+ 
+ 	/* sync/async unlink faults aren't errors */
+ 	if (urb->status) {
+ 		if (!(urb->status == -ENOENT ||
+ 		    urb->status == -ECONNRESET ||
+ 		    urb->status == -ESHUTDOWN)) {
+ 			pr_err("%s - nonzero write bulk status received: %d\n",
+ 				__func__, urb->status);
+ 			atomic_set(&dev->lost_pixels, 1);
+ 		}
+ 	}
+ 
+ 	urb->transfer_buffer_length = dev->urbs.size; /* reset to actual */
+ 
+ 	spin_lock_irqsave(&dev->urbs.lock, flags);
+ 	list_add_tail(&unode->entry, &dev->urbs.list);
+ 	dev->urbs.available++;
+ 	spin_unlock_irqrestore(&dev->urbs.lock, flags);
+ 
+ 	/*
+ 	 * When using fb_defio, we deadlock if up() is called
+ 	 * while another is waiting. So queue to another process.
+ 	 */
+ 	if (fb_defio)
+ 		schedule_delayed_work(&unode->release_urb_work, 0);
+ 	else
+ 		up(&dev->urbs.limit_sem);
+ }
+ 
+ static void dlfb_free_urb_list(struct dlfb_data *dev)
+ {
+ 	int count = dev->urbs.count;
+ 	struct list_head *node;
+ 	struct urb_node *unode;
+ 	struct urb *urb;
+ 	int ret;
+ 	unsigned long flags;
+ 
+ 	pr_notice("Waiting for completes and freeing all render urbs\n");
+ 
+ 	/* keep waiting and freeing, until we've got 'em all */
+ 	while (count--) {
+ 
+ 		/* Getting interrupted means a leak, but ok at shutdown*/
+ 		ret = down_interruptible(&dev->urbs.limit_sem);
+ 		if (ret)
+ 			break;
+ 
+ 		spin_lock_irqsave(&dev->urbs.lock, flags);
+ 
+ 		node = dev->urbs.list.next; /* have reserved one with sem */
+ 		list_del_init(node);
+ 
+ 		spin_unlock_irqrestore(&dev->urbs.lock, flags);
+ 
+ 		unode = list_entry(node, struct urb_node, entry);
+ 		urb = unode->urb;
+ 
+ 		/* Free each separately allocated piece */
+ 		usb_free_coherent(urb->dev, dev->urbs.size,
+ 				  urb->transfer_buffer, urb->transfer_dma);
+ 		usb_free_urb(urb);
+ 		kfree(node);
+ 	}
+ 
+ }
+ 
+ static int dlfb_alloc_urb_list(struct dlfb_data *dev, int count, size_t size)
+ {
+ 	int i = 0;
+ 	struct urb *urb;
+ 	struct urb_node *unode;
+ 	char *buf;
+ 
+ 	spin_lock_init(&dev->urbs.lock);
+ 
+ 	dev->urbs.size = size;
+ 	INIT_LIST_HEAD(&dev->urbs.list);
+ 
+ 	while (i < count) {
+ 		unode = kzalloc(sizeof(struct urb_node), GFP_KERNEL);
+ 		if (!unode)
+ 			break;
+ 		unode->dev = dev;
+ 
+ 		INIT_DELAYED_WORK(&unode->release_urb_work,
+ 			  dlfb_release_urb_work);
+ 
+ 		urb = usb_alloc_urb(0, GFP_KERNEL);
+ 		if (!urb) {
+ 			kfree(unode);
+ 			break;
+ 		}
+ 		unode->urb = urb;
+ 
+ 		buf = usb_alloc_coherent(dev->udev, MAX_TRANSFER, GFP_KERNEL,
+ 					 &urb->transfer_dma);
+ 		if (!buf) {
+ 			kfree(unode);
+ 			usb_free_urb(urb);
+ 			break;
+ 		}
+ 
+ 		/* urb->transfer_buffer_length set to actual before submit */
+ 		usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 1),
+ 			buf, size, dlfb_urb_completion, unode);
+ 		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+ 
+ 		list_add_tail(&unode->entry, &dev->urbs.list);
+ 
+ 		i++;
+ 	}
+ 
+ 	sema_init(&dev->urbs.limit_sem, i);
+ 	dev->urbs.count = i;
+ 	dev->urbs.available = i;
+ 
+ 	pr_notice("allocated %d %d byte urbs\n", i, (int) size);
+ 
+ 	return i;
+ }
+ 
+ static struct urb *dlfb_get_urb(struct dlfb_data *dev)
+ {
+ 	int ret = 0;
+ 	struct list_head *entry;
+ 	struct urb_node *unode;
+ 	struct urb *urb = NULL;
+ 	unsigned long flags;
+ 
+ 	/* Wait for an in-flight buffer to complete and get re-queued */
+ 	ret = down_timeout(&dev->urbs.limit_sem, GET_URB_TIMEOUT);
+ 	if (ret) {
+ 		atomic_set(&dev->lost_pixels, 1);
+ 		pr_warn("wait for urb interrupted: %x available: %d\n",
+ 		       ret, dev->urbs.available);
+ 		goto error;
+ 	}
+ 
+ 	spin_lock_irqsave(&dev->urbs.lock, flags);
+ 
+ 	BUG_ON(list_empty(&dev->urbs.list)); /* reserved one with limit_sem */
+ 	entry = dev->urbs.list.next;
+ 	list_del_init(entry);
+ 	dev->urbs.available--;
+ 
+ 	spin_unlock_irqrestore(&dev->urbs.lock, flags);
+ 
+ 	unode = list_entry(entry, struct urb_node, entry);
+ 	urb = unode->urb;
+ 
+ error:
+ 	return urb;
+ }
+ 
+ static int dlfb_submit_urb(struct dlfb_data *dev, struct urb *urb, size_t len)
+ {
+ 	int ret;
+ 
+ 	BUG_ON(len > dev->urbs.size);
+ 
+ 	urb->transfer_buffer_length = len; /* set to actual payload len */
+ 	ret = usb_submit_urb(urb, GFP_KERNEL);
+ 	if (ret) {
+ 		dlfb_urb_completion(urb); /* because no one else will */
+ 		atomic_set(&dev->lost_pixels, 1);
+ 		pr_err("usb_submit_urb error %x\n", ret);
+ 	}
+ 	return ret;
+ }
+ 
+ module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
+ MODULE_PARM_DESC(console, "Allow fbcon to consume first framebuffer found");
+ 
+ module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
+ MODULE_PARM_DESC(fb_defio, "Enable fb_defio mmap support. *Experimental*");
+ 
+ MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
+ 	      "Jaya Kumar <jayakumar.lkml@gmail.com>, "
+ 	      "Bernie Thompson <bernie@plugable.com>");
+ MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
+ MODULE_LICENSE("GPL");
+