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fbmon.c

/*
 * linux/drivers/video/fbmon.c
 *
 * Copyright (C) 2002 James Simmons <jsimmons@users.sf.net>
 *
 * Credits:
 * 
 * The EDID Parser is a conglomeration from the following sources:
 *
 *   1. SciTech SNAP Graphics Architecture
 *      Copyright (C) 1991-2002 SciTech Software, Inc. All rights reserved.
 *
 *   2. XFree86 4.3.0, interpret_edid.c
 *      Copyright 1998 by Egbert Eich <Egbert.Eich@Physik.TU-Darmstadt.DE>
 * 
 *   3. John Fremlin <vii@users.sourceforge.net> and 
 *      Ani Joshi <ajoshi@unixbox.com>
 *  
 * Generalized Timing Formula is derived from:
 *
 *      GTF Spreadsheet by Andy Morrish (1/5/97) 
 *      available at http://www.vesa.org
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 *
 */
#include <linux/fb.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <video/edid.h>
#ifdef CONFIG_PPC_OF
#include <asm/prom.h>
#include <asm/pci-bridge.h>
#endif
#include "edid.h"

/* 
 * EDID parser
 */

#undef DEBUG  /* define this for verbose EDID parsing output */

#ifdef DEBUG
#define DPRINTK(fmt, args...) printk(fmt,## args)
#else
#define DPRINTK(fmt, args...)
#endif

#define FBMON_FIX_HEADER  1
#define FBMON_FIX_INPUT   2
#define FBMON_FIX_TIMINGS 3

#ifdef CONFIG_FB_MODE_HELPERS
struct broken_edid {
      u8  manufacturer[4];
      u32 model;
      u32 fix;
};

static const struct broken_edid brokendb[] = {
      /* DEC FR-PCXAV-YZ */
      {
            .manufacturer = "DEC",
            .model        = 0x073a,
            .fix          = FBMON_FIX_HEADER,
      },
      /* ViewSonic PF775a */
      {
            .manufacturer = "VSC",
            .model        = 0x5a44,
            .fix          = FBMON_FIX_INPUT,
      },
      /* Sharp UXGA? */
      {
            .manufacturer = "SHP",
            .model        = 0x138e,
            .fix          = FBMON_FIX_TIMINGS,
      },
};

static const unsigned char edid_v1_header[] = { 0x00, 0xff, 0xff, 0xff,
      0xff, 0xff, 0xff, 0x00
};

static void copy_string(unsigned char *c, unsigned char *s)
{
  int i;
  c = c + 5;
  for (i = 0; (i < 13 && *c != 0x0A); i++)
    *(s++) = *(c++);
  *s = 0;
  while (i-- && (*--s == 0x20)) *s = 0;
}

static int edid_is_serial_block(unsigned char *block)
{
      if ((block[0] == 0x00) && (block[1] == 0x00) &&
          (block[2] == 0x00) && (block[3] == 0xff) &&
          (block[4] == 0x00))
            return 1;
      else
            return 0;
}

static int edid_is_ascii_block(unsigned char *block)
{
      if ((block[0] == 0x00) && (block[1] == 0x00) &&
          (block[2] == 0x00) && (block[3] == 0xfe) &&
          (block[4] == 0x00))
            return 1;
      else
            return 0;
}

static int edid_is_limits_block(unsigned char *block)
{
      if ((block[0] == 0x00) && (block[1] == 0x00) &&
          (block[2] == 0x00) && (block[3] == 0xfd) &&
          (block[4] == 0x00))
            return 1;
      else
            return 0;
}

static int edid_is_monitor_block(unsigned char *block)
{
      if ((block[0] == 0x00) && (block[1] == 0x00) &&
          (block[2] == 0x00) && (block[3] == 0xfc) &&
          (block[4] == 0x00))
            return 1;
      else
            return 0;
}

static int edid_is_timing_block(unsigned char *block)
{
      if ((block[0] != 0x00) || (block[1] != 0x00) ||
          (block[2] != 0x00) || (block[4] != 0x00))
            return 1;
      else
            return 0;
}

static int check_edid(unsigned char *edid)
{
      unsigned char *block = edid + ID_MANUFACTURER_NAME, manufacturer[4];
      unsigned char *b;
      u32 model;
      int i, fix = 0, ret = 0;

      manufacturer[0] = ((block[0] & 0x7c) >> 2) + '@';
      manufacturer[1] = ((block[0] & 0x03) << 3) +
            ((block[1] & 0xe0) >> 5) + '@';
      manufacturer[2] = (block[1] & 0x1f) + '@';
      manufacturer[3] = 0;
      model = block[2] + (block[3] << 8);

      for (i = 0; i < ARRAY_SIZE(brokendb); i++) {
            if (!strncmp(manufacturer, brokendb[i].manufacturer, 4) &&
                  brokendb[i].model == model) {
                  fix = brokendb[i].fix;
                  break;
            }
      }

      switch (fix) {
      case FBMON_FIX_HEADER:
            for (i = 0; i < 8; i++) {
                  if (edid[i] != edid_v1_header[i]) {
                        ret = fix;
                        break;
                  }
            }
            break;
      case FBMON_FIX_INPUT:
            b = edid + EDID_STRUCT_DISPLAY;
            /* Only if display is GTF capable will
               the input type be reset to analog */
            if (b[4] & 0x01 && b[0] & 0x80)
                  ret = fix;
            break;
      case FBMON_FIX_TIMINGS:
            b = edid + DETAILED_TIMING_DESCRIPTIONS_START;
            ret = fix;

            for (i = 0; i < 4; i++) {
                  if (edid_is_limits_block(b)) {
                        ret = 0;
                        break;
                  }

                  b += DETAILED_TIMING_DESCRIPTION_SIZE;
            }

            break;
      }

      if (ret)
            printk("fbmon: The EDID Block of "
                   "Manufacturer: %s Model: 0x%x is known to "
                   "be broken,\n",  manufacturer, model);

      return ret;
}

static void fix_edid(unsigned char *edid, int fix)
{
      int i;
      unsigned char *b, csum = 0;

      switch (fix) {
      case FBMON_FIX_HEADER:
            printk("fbmon: trying a header reconstruct\n");
            memcpy(edid, edid_v1_header, 8);
            break;
      case FBMON_FIX_INPUT:
            printk("fbmon: trying to fix input type\n");
            b = edid + EDID_STRUCT_DISPLAY;
            b[0] &= ~0x80;
            edid[127] += 0x80;
            break;
      case FBMON_FIX_TIMINGS:
            printk("fbmon: trying to fix monitor timings\n");
            b = edid + DETAILED_TIMING_DESCRIPTIONS_START;
            for (i = 0; i < 4; i++) {
                  if (!(edid_is_serial_block(b) ||
                        edid_is_ascii_block(b) ||
                        edid_is_monitor_block(b) ||
                        edid_is_timing_block(b))) {
                        b[0] = 0x00;
                        b[1] = 0x00;
                        b[2] = 0x00;
                        b[3] = 0xfd;
                        b[4] = 0x00;
                        b[5] = 60;   /* vfmin */
                        b[6] = 60;   /* vfmax */
                        b[7] = 30;   /* hfmin */
                        b[8] = 75;   /* hfmax */
                        b[9] = 17;   /* pixclock - 170 MHz*/
                        b[10] = 0;   /* GTF */
                        break;
                  }

                  b += DETAILED_TIMING_DESCRIPTION_SIZE;
            }

            for (i = 0; i < EDID_LENGTH - 1; i++)
                  csum += edid[i];

            edid[127] = 256 - csum;
            break;
      }
}

static int edid_checksum(unsigned char *edid)
{
      unsigned char i, csum = 0, all_null = 0;
      int err = 0, fix = check_edid(edid);

      if (fix)
            fix_edid(edid, fix);

      for (i = 0; i < EDID_LENGTH; i++) {
            csum += edid[i];
            all_null |= edid[i];
      }

      if (csum == 0x00 && all_null) {
            /* checksum passed, everything's good */
            err = 1;
      }

      return err;
}

static int edid_check_header(unsigned char *edid)
{
      int i, err = 1, fix = check_edid(edid);

      if (fix)
            fix_edid(edid, fix);

      for (i = 0; i < 8; i++) {
            if (edid[i] != edid_v1_header[i])
                  err = 0;
      }

      return err;
}

static void parse_vendor_block(unsigned char *block, struct fb_monspecs *specs)
{
      specs->manufacturer[0] = ((block[0] & 0x7c) >> 2) + '@';
      specs->manufacturer[1] = ((block[0] & 0x03) << 3) +
            ((block[1] & 0xe0) >> 5) + '@';
      specs->manufacturer[2] = (block[1] & 0x1f) + '@';
      specs->manufacturer[3] = 0;
      specs->model = block[2] + (block[3] << 8);
      specs->serial = block[4] + (block[5] << 8) +
             (block[6] << 16) + (block[7] << 24);
      specs->year = block[9] + 1990;
      specs->week = block[8];
      DPRINTK("   Manufacturer: %s\n", specs->manufacturer);
      DPRINTK("   Model: %x\n", specs->model);
      DPRINTK("   Serial#: %u\n", specs->serial);
      DPRINTK("   Year: %u Week %u\n", specs->year, specs->week);
}

static void get_dpms_capabilities(unsigned char flags,
                          struct fb_monspecs *specs)
{
      specs->dpms = 0;
      if (flags & DPMS_ACTIVE_OFF)
            specs->dpms |= FB_DPMS_ACTIVE_OFF;
      if (flags & DPMS_SUSPEND)
            specs->dpms |= FB_DPMS_SUSPEND;
      if (flags & DPMS_STANDBY)
            specs->dpms |= FB_DPMS_STANDBY;
      DPRINTK("      DPMS: Active %s, Suspend %s, Standby %s\n",
             (flags & DPMS_ACTIVE_OFF) ? "yes" : "no",
             (flags & DPMS_SUSPEND)    ? "yes" : "no",
             (flags & DPMS_STANDBY)    ? "yes" : "no");
}
      
static void get_chroma(unsigned char *block, struct fb_monspecs *specs)
{
      int tmp;

      DPRINTK("      Chroma\n");
      /* Chromaticity data */
      tmp = ((block[5] & (3 << 6)) >> 6) | (block[0x7] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.redx = tmp/1024;
      DPRINTK("         RedX:     0.%03d ", specs->chroma.redx);

      tmp = ((block[5] & (3 << 4)) >> 4) | (block[0x8] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.redy = tmp/1024;
      DPRINTK("RedY:     0.%03d\n", specs->chroma.redy);

      tmp = ((block[5] & (3 << 2)) >> 2) | (block[0x9] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.greenx = tmp/1024;
      DPRINTK("         GreenX:   0.%03d ", specs->chroma.greenx);

      tmp = (block[5] & 3) | (block[0xa] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.greeny = tmp/1024;
      DPRINTK("GreenY:   0.%03d\n", specs->chroma.greeny);

      tmp = ((block[6] & (3 << 6)) >> 6) | (block[0xb] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.bluex = tmp/1024;
      DPRINTK("         BlueX:    0.%03d ", specs->chroma.bluex);

      tmp = ((block[6] & (3 << 4)) >> 4) | (block[0xc] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.bluey = tmp/1024;
      DPRINTK("BlueY:    0.%03d\n", specs->chroma.bluey);
      
      tmp = ((block[6] & (3 << 2)) >> 2) | (block[0xd] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.whitex = tmp/1024;
      DPRINTK("         WhiteX:   0.%03d ", specs->chroma.whitex);

      tmp = (block[6] & 3) | (block[0xe] << 2);
      tmp *= 1000;
      tmp += 512;
      specs->chroma.whitey = tmp/1024;
      DPRINTK("WhiteY:   0.%03d\n", specs->chroma.whitey);
}

static void calc_mode_timings(int xres, int yres, int refresh,
                        struct fb_videomode *mode)
{
      struct fb_var_screeninfo *var;
      
      var = kzalloc(sizeof(struct fb_var_screeninfo), GFP_KERNEL);

      if (var) {
            var->xres = xres;
            var->yres = yres;
            fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON,
                      refresh, var, NULL);
            mode->xres = xres;
            mode->yres = yres;
            mode->pixclock = var->pixclock;
            mode->refresh = refresh;
            mode->left_margin = var->left_margin;
            mode->right_margin = var->right_margin;
            mode->upper_margin = var->upper_margin;
            mode->lower_margin = var->lower_margin;
            mode->hsync_len = var->hsync_len;
            mode->vsync_len = var->vsync_len;
            mode->vmode = 0;
            mode->sync = 0;
            kfree(var);
      }
}

static int get_est_timing(unsigned char *block, struct fb_videomode *mode)
{
      int num = 0;
      unsigned char c;

      c = block[0];
      if (c&0x80) {
            calc_mode_timings(720, 400, 70, &mode[num]);
            mode[num++].flag = FB_MODE_IS_CALCULATED;
            DPRINTK("      720x400@70Hz\n");
      }
      if (c&0x40) {
            calc_mode_timings(720, 400, 88, &mode[num]);
            mode[num++].flag = FB_MODE_IS_CALCULATED;
            DPRINTK("      720x400@88Hz\n");
      }
      if (c&0x20) {
            mode[num++] = vesa_modes[3];
            DPRINTK("      640x480@60Hz\n");
      }
      if (c&0x10) {
            calc_mode_timings(640, 480, 67, &mode[num]);
            mode[num++].flag = FB_MODE_IS_CALCULATED;
            DPRINTK("      640x480@67Hz\n");
      }
      if (c&0x08) {
            mode[num++] = vesa_modes[4];
            DPRINTK("      640x480@72Hz\n");
      }
      if (c&0x04) {
            mode[num++] = vesa_modes[5];
            DPRINTK("      640x480@75Hz\n");
      }
      if (c&0x02) {
            mode[num++] = vesa_modes[7];
            DPRINTK("      800x600@56Hz\n");
      }
      if (c&0x01) {
            mode[num++] = vesa_modes[8];
            DPRINTK("      800x600@60Hz\n");
      }

      c = block[1];
      if (c&0x80) {
            mode[num++] = vesa_modes[9];
            DPRINTK("      800x600@72Hz\n");
      }
      if (c&0x40) {
            mode[num++] = vesa_modes[10];
            DPRINTK("      800x600@75Hz\n");
      }
      if (c&0x20) {
            calc_mode_timings(832, 624, 75, &mode[num]);
            mode[num++].flag = FB_MODE_IS_CALCULATED;
            DPRINTK("      832x624@75Hz\n");
      }
      if (c&0x10) {
            mode[num++] = vesa_modes[12];
            DPRINTK("      1024x768@87Hz Interlaced\n");
      }
      if (c&0x08) {
            mode[num++] = vesa_modes[13];
            DPRINTK("      1024x768@60Hz\n");
      }
      if (c&0x04) {
            mode[num++] = vesa_modes[14];
            DPRINTK("      1024x768@70Hz\n");
      }
      if (c&0x02) {
            mode[num++] = vesa_modes[15];
            DPRINTK("      1024x768@75Hz\n");
      }
      if (c&0x01) {
            mode[num++] = vesa_modes[21];
            DPRINTK("      1280x1024@75Hz\n");
      }
      c = block[2];
      if (c&0x80) {
            mode[num++] = vesa_modes[17];
            DPRINTK("      1152x870@75Hz\n");
      }
      DPRINTK("      Manufacturer's mask: %x\n",c&0x7F);
      return num;
}

static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
{
      int xres, yres = 0, refresh, ratio, i;
      
      xres = (block[0] + 31) * 8;
      if (xres <= 256)
            return 0;

      ratio = (block[1] & 0xc0) >> 6;
      switch (ratio) {
      case 0:
            yres = xres;
            break;
      case 1:
            yres = (xres * 3)/4;
            break;
      case 2:
            yres = (xres * 4)/5;
            break;
      case 3:
            yres = (xres * 9)/16;
            break;
      }
      refresh = (block[1] & 0x3f) + 60;

      DPRINTK("      %dx%d@%dHz\n", xres, yres, refresh);
      for (i = 0; i < VESA_MODEDB_SIZE; i++) {
            if (vesa_modes[i].xres == xres && 
                vesa_modes[i].yres == yres &&
                vesa_modes[i].refresh == refresh) {
                  *mode = vesa_modes[i];
                  mode->flag |= FB_MODE_IS_STANDARD;
                  return 1;
            }
      }
      calc_mode_timings(xres, yres, refresh, mode);
      return 1;
}

static int get_dst_timing(unsigned char *block,
                    struct fb_videomode *mode)
{
      int j, num = 0;

      for (j = 0; j < 6; j++, block+= STD_TIMING_DESCRIPTION_SIZE) 
            num += get_std_timing(block, &mode[num]);

      return num;
}

static void get_detailed_timing(unsigned char *block, 
                        struct fb_videomode *mode)
{
      mode->xres = H_ACTIVE;
      mode->yres = V_ACTIVE;
      mode->pixclock = PIXEL_CLOCK;
      mode->pixclock /= 1000;
      mode->pixclock = KHZ2PICOS(mode->pixclock);
      mode->right_margin = H_SYNC_OFFSET;
      mode->left_margin = (H_ACTIVE + H_BLANKING) -
            (H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH);
      mode->upper_margin = V_BLANKING - V_SYNC_OFFSET - 
            V_SYNC_WIDTH;
      mode->lower_margin = V_SYNC_OFFSET;
      mode->hsync_len = H_SYNC_WIDTH;
      mode->vsync_len = V_SYNC_WIDTH;
      if (HSYNC_POSITIVE)
            mode->sync |= FB_SYNC_HOR_HIGH_ACT;
      if (VSYNC_POSITIVE)
            mode->sync |= FB_SYNC_VERT_HIGH_ACT;
      mode->refresh = PIXEL_CLOCK/((H_ACTIVE + H_BLANKING) *
                             (V_ACTIVE + V_BLANKING));
      mode->vmode = 0;
      mode->flag = FB_MODE_IS_DETAILED;

      DPRINTK("      %d MHz ",  PIXEL_CLOCK/1000000);
      DPRINTK("%d %d %d %d ", H_ACTIVE, H_ACTIVE + H_SYNC_OFFSET,
             H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH, H_ACTIVE + H_BLANKING);
      DPRINTK("%d %d %d %d ", V_ACTIVE, V_ACTIVE + V_SYNC_OFFSET,
             V_ACTIVE + V_SYNC_OFFSET + V_SYNC_WIDTH, V_ACTIVE + V_BLANKING);
      DPRINTK("%sHSync %sVSync\n\n", (HSYNC_POSITIVE) ? "+" : "-",
             (VSYNC_POSITIVE) ? "+" : "-");
}

/**
 * fb_create_modedb - create video mode database
 * @edid: EDID data
 * @dbsize: database size
 *
 * RETURNS: struct fb_videomode, @dbsize contains length of database
 *
 * DESCRIPTION:
 * This function builds a mode database using the contents of the EDID
 * data
 */
static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize)
{
      struct fb_videomode *mode, *m;
      unsigned char *block;
      int num = 0, i, first = 1;

      mode = kzalloc(50 * sizeof(struct fb_videomode), GFP_KERNEL);
      if (mode == NULL)
            return NULL;

      if (edid == NULL || !edid_checksum(edid) || 
          !edid_check_header(edid)) {
            kfree(mode);
            return NULL;
      }

      *dbsize = 0;

      DPRINTK("   Detailed Timings\n");
      block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
      for (i = 0; i < 4; i++, block+= DETAILED_TIMING_DESCRIPTION_SIZE) {
            if (!(block[0] == 0x00 && block[1] == 0x00)) {
                  get_detailed_timing(block, &mode[num]);
                  if (first) {
                          mode[num].flag |= FB_MODE_IS_FIRST;
                        first = 0;
                  }
                  num++;
            }
      }

      DPRINTK("   Supported VESA Modes\n");
      block = edid + ESTABLISHED_TIMING_1;
      num += get_est_timing(block, &mode[num]);

      DPRINTK("   Standard Timings\n");
      block = edid + STD_TIMING_DESCRIPTIONS_START;
      for (i = 0; i < STD_TIMING; i++, block += STD_TIMING_DESCRIPTION_SIZE)
            num += get_std_timing(block, &mode[num]);

      block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
      for (i = 0; i < 4; i++, block+= DETAILED_TIMING_DESCRIPTION_SIZE) {
            if (block[0] == 0x00 && block[1] == 0x00 && block[3] == 0xfa)
                  num += get_dst_timing(block + 5, &mode[num]);
      }
      
      /* Yikes, EDID data is totally useless */
      if (!num) {
            kfree(mode);
            return NULL;
      }

      *dbsize = num;
      m = kmalloc(num * sizeof(struct fb_videomode), GFP_KERNEL);
      if (!m)
            return mode;
      memmove(m, mode, num * sizeof(struct fb_videomode));
      kfree(mode);
      return m;
}

/**
 * fb_destroy_modedb - destroys mode database
 * @modedb: mode database to destroy
 *
 * DESCRIPTION:
 * Destroy mode database created by fb_create_modedb
 */
void fb_destroy_modedb(struct fb_videomode *modedb)
{
      kfree(modedb);
}

static int fb_get_monitor_limits(unsigned char *edid, struct fb_monspecs *specs)
{
      int i, retval = 1;
      unsigned char *block;

      block = edid + DETAILED_TIMING_DESCRIPTIONS_START;

      DPRINTK("      Monitor Operating Limits: ");

      for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
            if (edid_is_limits_block(block)) {
                  specs->hfmin = H_MIN_RATE * 1000;
                  specs->hfmax = H_MAX_RATE * 1000;
                  specs->vfmin = V_MIN_RATE;
                  specs->vfmax = V_MAX_RATE;
                  specs->dclkmax = MAX_PIXEL_CLOCK * 1000000;
                  specs->gtf = (GTF_SUPPORT) ? 1 : 0;
                  retval = 0;
                  DPRINTK("From EDID\n");
                  break;
            }
      }

      /* estimate monitor limits based on modes supported */
      if (retval) {
            struct fb_videomode *modes, *mode;
            int num_modes, i, hz, hscan, pixclock;
            int vtotal, htotal;

            modes = fb_create_modedb(edid, &num_modes);
            if (!modes) {
                  DPRINTK("None Available\n");
                  return 1;
            }

            retval = 0;
            for (i = 0; i < num_modes; i++) {
                  mode = &modes[i];
                  pixclock = PICOS2KHZ(modes[i].pixclock) * 1000;
                  htotal = mode->xres + mode->right_margin + mode->hsync_len
                        + mode->left_margin;
                  vtotal = mode->yres + mode->lower_margin + mode->vsync_len
                        + mode->upper_margin;

                  if (mode->vmode & FB_VMODE_INTERLACED)
                        vtotal /= 2;

                  if (mode->vmode & FB_VMODE_DOUBLE)
                        vtotal *= 2;

                  hscan = (pixclock + htotal / 2) / htotal;
                  hscan = (hscan + 500) / 1000 * 1000;
                  hz = (hscan + vtotal / 2) / vtotal;
                  
                  if (specs->dclkmax == 0 || specs->dclkmax < pixclock)
                        specs->dclkmax = pixclock;

                  if (specs->dclkmin == 0 || specs->dclkmin > pixclock)
                        specs->dclkmin = pixclock;

                  if (specs->hfmax == 0 || specs->hfmax < hscan)
                        specs->hfmax = hscan;

                  if (specs->hfmin == 0 || specs->hfmin > hscan)
                        specs->hfmin = hscan;

                  if (specs->vfmax == 0 || specs->vfmax < hz)
                        specs->vfmax = hz;

                  if (specs->vfmin == 0 || specs->vfmin > hz)
                        specs->vfmin = hz;
            }
            DPRINTK("Extrapolated\n");
            fb_destroy_modedb(modes);
      }
      DPRINTK("           H: %d-%dKHz V: %d-%dHz DCLK: %dMHz\n",
            specs->hfmin/1000, specs->hfmax/1000, specs->vfmin,
            specs->vfmax, specs->dclkmax/1000000);
      return retval;
}

static void get_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
      unsigned char c, *block;

      block = edid + EDID_STRUCT_DISPLAY;

      fb_get_monitor_limits(edid, specs);

      c = block[0] & 0x80;
      specs->input = 0;
      if (c) {
            specs->input |= FB_DISP_DDI;
            DPRINTK("      Digital Display Input");
      } else {
            DPRINTK("      Analog Display Input: Input Voltage - ");
            switch ((block[0] & 0x60) >> 5) {
            case 0:
                  DPRINTK("0.700V/0.300V");
                  specs->input |= FB_DISP_ANA_700_300;
                  break;
            case 1:
                  DPRINTK("0.714V/0.286V");
                  specs->input |= FB_DISP_ANA_714_286;
                  break;
            case 2:
                  DPRINTK("1.000V/0.400V");
                  specs->input |= FB_DISP_ANA_1000_400;
                  break;
            case 3:
                  DPRINTK("0.700V/0.000V");
                  specs->input |= FB_DISP_ANA_700_000;
                  break;
            }
      }
      DPRINTK("\n      Sync: ");
      c = block[0] & 0x10;
      if (c)
            DPRINTK("      Configurable signal level\n");
      c = block[0] & 0x0f;
      specs->signal = 0;
      if (c & 0x10) {
            DPRINTK("Blank to Blank ");
            specs->signal |= FB_SIGNAL_BLANK_BLANK;
      }
      if (c & 0x08) {
            DPRINTK("Separate ");
            specs->signal |= FB_SIGNAL_SEPARATE;
      }
      if (c & 0x04) {
            DPRINTK("Composite ");
            specs->signal |= FB_SIGNAL_COMPOSITE;
      }
      if (c & 0x02) {
            DPRINTK("Sync on Green ");
            specs->signal |= FB_SIGNAL_SYNC_ON_GREEN;
      }
      if (c & 0x01) {
            DPRINTK("Serration on ");
            specs->signal |= FB_SIGNAL_SERRATION_ON;
      }
      DPRINTK("\n");
      specs->max_x = block[1];
      specs->max_y = block[2];
      DPRINTK("      Max H-size in cm: ");
      if (specs->max_x)
            DPRINTK("%d\n", specs->max_x);
      else
            DPRINTK("variable\n");
      DPRINTK("      Max V-size in cm: ");
      if (specs->max_y)
            DPRINTK("%d\n", specs->max_y);
      else
            DPRINTK("variable\n");

      c = block[3];
      specs->gamma = c+100;
      DPRINTK("      Gamma: ");
      DPRINTK("%d.%d\n", specs->gamma/100, specs->gamma % 100);

      get_dpms_capabilities(block[4], specs);

      switch ((block[4] & 0x18) >> 3) {
      case 0:
            DPRINTK("      Monochrome/Grayscale\n");
            specs->input |= FB_DISP_MONO;
            break;
      case 1:
            DPRINTK("      RGB Color Display\n");
            specs->input |= FB_DISP_RGB;
            break;
      case 2:
            DPRINTK("      Non-RGB Multicolor Display\n");
            specs->input |= FB_DISP_MULTI;
            break;
      default:
            DPRINTK("      Unknown\n");
            specs->input |= FB_DISP_UNKNOWN;
            break;
      }

      get_chroma(block, specs);

      specs->misc = 0;
      c = block[4] & 0x7;
      if (c & 0x04) {
            DPRINTK("      Default color format is primary\n");
            specs->misc |= FB_MISC_PRIM_COLOR;
      }
      if (c & 0x02) {
            DPRINTK("      First DETAILED Timing is preferred\n");
            specs->misc |= FB_MISC_1ST_DETAIL;
      }
      if (c & 0x01) {
            printk("      Display is GTF capable\n");
            specs->gtf = 1;
      }
}

int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
{
      int i;
      unsigned char *block;

      if (edid == NULL || var == NULL)
            return 1;

      if (!(edid_checksum(edid)))
            return 1;

      if (!(edid_check_header(edid)))
            return 1;

      block = edid + DETAILED_TIMING_DESCRIPTIONS_START;

      for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
            if (edid_is_timing_block(block)) {
                  var->xres = var->xres_virtual = H_ACTIVE;
                  var->yres = var->yres_virtual = V_ACTIVE;
                  var->height = var->width = -1;
                  var->right_margin = H_SYNC_OFFSET;
                  var->left_margin = (H_ACTIVE + H_BLANKING) -
                        (H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH);
                  var->upper_margin = V_BLANKING - V_SYNC_OFFSET -
                        V_SYNC_WIDTH;
                  var->lower_margin = V_SYNC_OFFSET;
                  var->hsync_len = H_SYNC_WIDTH;
                  var->vsync_len = V_SYNC_WIDTH;
                  var->pixclock = PIXEL_CLOCK;
                  var->pixclock /= 1000;
                  var->pixclock = KHZ2PICOS(var->pixclock);

                  if (HSYNC_POSITIVE)
                        var->sync |= FB_SYNC_HOR_HIGH_ACT;
                  if (VSYNC_POSITIVE)
                        var->sync |= FB_SYNC_VERT_HIGH_ACT;
                  return 0;
            }
      }
      return 1;
}

void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
      unsigned char *block;
      int i, found = 0;

      if (edid == NULL)
            return;

      if (!(edid_checksum(edid)))
            return;

      if (!(edid_check_header(edid)))
            return;

      memset(specs, 0, sizeof(struct fb_monspecs));

      specs->version = edid[EDID_STRUCT_VERSION];
      specs->revision = edid[EDID_STRUCT_REVISION];

      DPRINTK("========================================\n");
      DPRINTK("Display Information (EDID)\n");
      DPRINTK("========================================\n");
      DPRINTK("   EDID Version %d.%d\n", (int) specs->version,
             (int) specs->revision);

      parse_vendor_block(edid + ID_MANUFACTURER_NAME, specs);

      block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
      for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
            if (edid_is_serial_block(block)) {
                  copy_string(block, specs->serial_no);
                  DPRINTK("   Serial Number: %s\n", specs->serial_no);
            } else if (edid_is_ascii_block(block)) {
                  copy_string(block, specs->ascii);
                  DPRINTK("   ASCII Block: %s\n", specs->ascii);
            } else if (edid_is_monitor_block(block)) {
                  copy_string(block, specs->monitor);
                  DPRINTK("   Monitor Name: %s\n", specs->monitor);
            }
      }

      DPRINTK("   Display Characteristics:\n");
      get_monspecs(edid, specs);

      specs->modedb = fb_create_modedb(edid, &specs->modedb_len);

      /*
       * Workaround for buggy EDIDs that sets that the first
       * detailed timing is preferred but has not detailed
       * timing specified
       */
      for (i = 0; i < specs->modedb_len; i++) {
            if (specs->modedb[i].flag & FB_MODE_IS_DETAILED) {
                  found = 1;
                  break;
            }
      }

      if (!found)
            specs->misc &= ~FB_MISC_1ST_DETAIL;

      DPRINTK("========================================\n");
}

/* 
 * VESA Generalized Timing Formula (GTF) 
 */

#define FLYBACK                     550
#define V_FRONTPORCH                1
#define H_OFFSET                    40
#define H_SCALEFACTOR               20
#define H_BLANKSCALE                128
#define H_GRADIENT                  600
#define C_VAL                       30
#define M_VAL                       300

struct __fb_timings {
      u32 dclk;
      u32 hfreq;
      u32 vfreq;
      u32 hactive;
      u32 vactive;
      u32 hblank;
      u32 vblank;
      u32 htotal;
      u32 vtotal;
};

/**
 * fb_get_vblank - get vertical blank time
 * @hfreq: horizontal freq
 *
 * DESCRIPTION:
 * vblank = right_margin + vsync_len + left_margin 
 *
 *    given: right_margin = 1 (V_FRONTPORCH)
 *           vsync_len    = 3
 *           flyback      = 550
 *
 *                          flyback * hfreq
 *           left_margin  = --------------- - vsync_len
 *                           1000000
 */
static u32 fb_get_vblank(u32 hfreq)
{
      u32 vblank;

      vblank = (hfreq * FLYBACK)/1000; 
      vblank = (vblank + 500)/1000;
      return (vblank + V_FRONTPORCH);
}

/** 
 * fb_get_hblank_by_freq - get horizontal blank time given hfreq
 * @hfreq: horizontal freq
 * @xres: horizontal resolution in pixels
 *
 * DESCRIPTION:
 *
 *           xres * duty_cycle
 * hblank = ------------------
 *           100 - duty_cycle
 *
 * duty cycle = percent of htotal assigned to inactive display
 * duty cycle = C - (M/Hfreq)
 *
 * where: C = ((offset - scale factor) * blank_scale)
 *            -------------------------------------- + scale factor
 *                        256 
 *        M = blank_scale * gradient
 *
 */
static u32 fb_get_hblank_by_hfreq(u32 hfreq, u32 xres)
{
      u32 c_val, m_val, duty_cycle, hblank;

      c_val = (((H_OFFSET - H_SCALEFACTOR) * H_BLANKSCALE)/256 + 
             H_SCALEFACTOR) * 1000;
      m_val = (H_BLANKSCALE * H_GRADIENT)/256;
      m_val = (m_val * 1000000)/hfreq;
      duty_cycle = c_val - m_val;
      hblank = (xres * duty_cycle)/(100000 - duty_cycle);
      return (hblank);
}

/** 
 * fb_get_hblank_by_dclk - get horizontal blank time given pixelclock
 * @dclk: pixelclock in Hz
 * @xres: horizontal resolution in pixels
 *
 * DESCRIPTION:
 *
 *           xres * duty_cycle
 * hblank = ------------------
 *           100 - duty_cycle
 *
 * duty cycle = percent of htotal assigned to inactive display
 * duty cycle = C - (M * h_period)
 * 
 * where: h_period = SQRT(100 - C + (0.4 * xres * M)/dclk) + C - 100
 *                   -----------------------------------------------
 *                                    2 * M
 *        M = 300;
 *        C = 30;

 */
static u32 fb_get_hblank_by_dclk(u32 dclk, u32 xres)
{
      u32 duty_cycle, h_period, hblank;

      dclk /= 1000;
      h_period = 100 - C_VAL;
      h_period *= h_period;
      h_period += (M_VAL * xres * 2 * 1000)/(5 * dclk);
      h_period *=10000; 

      h_period = int_sqrt(h_period);
      h_period -= (100 - C_VAL) * 100;
      h_period *= 1000; 
      h_period /= 2 * M_VAL;

      duty_cycle = C_VAL * 1000 - (M_VAL * h_period)/100;
      hblank = (xres * duty_cycle)/(100000 - duty_cycle) + 8;
      hblank &= ~15;
      return (hblank);
}
      
/**
 * fb_get_hfreq - estimate hsync
 * @vfreq: vertical refresh rate
 * @yres: vertical resolution
 *
 * DESCRIPTION:
 *
 *          (yres + front_port) * vfreq * 1000000
 * hfreq = -------------------------------------
 *          (1000000 - (vfreq * FLYBACK)
 * 
 */

static u32 fb_get_hfreq(u32 vfreq, u32 yres)
{
      u32 divisor, hfreq;
      
      divisor = (1000000 - (vfreq * FLYBACK))/1000;
      hfreq = (yres + V_FRONTPORCH) * vfreq  * 1000;
      return (hfreq/divisor);
}

static void fb_timings_vfreq(struct __fb_timings *timings)
{
      timings->hfreq = fb_get_hfreq(timings->vfreq, timings->vactive);
      timings->vblank = fb_get_vblank(timings->hfreq);
      timings->vtotal = timings->vactive + timings->vblank;
      timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq, 
                                     timings->hactive);
      timings->htotal = timings->hactive + timings->hblank;
      timings->dclk = timings->htotal * timings->hfreq;
}

static void fb_timings_hfreq(struct __fb_timings *timings)
{
      timings->vblank = fb_get_vblank(timings->hfreq);
      timings->vtotal = timings->vactive + timings->vblank;
      timings->vfreq = timings->hfreq/timings->vtotal;
      timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq, 
                                     timings->hactive);
      timings->htotal = timings->hactive + timings->hblank;
      timings->dclk = timings->htotal * timings->hfreq;
}

static void fb_timings_dclk(struct __fb_timings *timings)
{
      timings->hblank = fb_get_hblank_by_dclk(timings->dclk, 
                                    timings->hactive);
      timings->htotal = timings->hactive + timings->hblank;
      timings->hfreq = timings->dclk/timings->htotal;
      timings->vblank = fb_get_vblank(timings->hfreq);
      timings->vtotal = timings->vactive + timings->vblank;
      timings->vfreq = timings->hfreq/timings->vtotal;
}

/*
 * fb_get_mode - calculates video mode using VESA GTF
 * @flags: if: 0 - maximize vertical refresh rate
 *             1 - vrefresh-driven calculation;
 *             2 - hscan-driven calculation;
 *             3 - pixelclock-driven calculation;
 * @val: depending on @flags, ignored, vrefresh, hsync or pixelclock
 * @var: pointer to fb_var_screeninfo
 * @info: pointer to fb_info
 *
 * DESCRIPTION:
 * Calculates video mode based on monitor specs using VESA GTF. 
 * The GTF is best for VESA GTF compliant monitors but is 
 * specifically formulated to work for older monitors as well.
 *
 * If @flag==0, the function will attempt to maximize the 
 * refresh rate.  Otherwise, it will calculate timings based on
 * the flag and accompanying value.  
 *
 * If FB_IGNOREMON bit is set in @flags, monitor specs will be 
 * ignored and @var will be filled with the calculated timings.
 *
 * All calculations are based on the VESA GTF Spreadsheet
 * available at VESA's public ftp (http://www.vesa.org).
 * 
 * NOTES:
 * The timings generated by the GTF will be different from VESA
 * DMT.  It might be a good idea to keep a table of standard
 * VESA modes as well.  The GTF may also not work for some displays,
 * such as, and especially, analog TV.
 *   
 * REQUIRES:
 * A valid info->monspecs, otherwise 'safe numbers' will be used.
 */ 
int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var, struct fb_info *info)
{
      struct __fb_timings *timings;
      u32 interlace = 1, dscan = 1;
      u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax, err = 0;


      timings = kzalloc(sizeof(struct __fb_timings), GFP_KERNEL);

      if (!timings)
            return -ENOMEM;

      /* 
       * If monspecs are invalid, use values that are enough
       * for 640x480@60
       */
      if (!info || !info->monspecs.hfmax || !info->monspecs.vfmax ||
          !info->monspecs.dclkmax ||
          info->monspecs.hfmax < info->monspecs.hfmin ||
          info->monspecs.vfmax < info->monspecs.vfmin ||
          info->monspecs.dclkmax < info->monspecs.dclkmin) {
            hfmin = 29000; hfmax = 30000;
            vfmin = 60; vfmax = 60;
            dclkmin = 0; dclkmax = 25000000;
      } else {
            hfmin = info->monspecs.hfmin;
            hfmax = info->monspecs.hfmax;
            vfmin = info->monspecs.vfmin;
            vfmax = info->monspecs.vfmax;
            dclkmin = info->monspecs.dclkmin;
            dclkmax = info->monspecs.dclkmax;
      }

      timings->hactive = var->xres;
      timings->vactive = var->yres;
      if (var->vmode & FB_VMODE_INTERLACED) { 
            timings->vactive /= 2;
            interlace = 2;
      }
      if (var->vmode & FB_VMODE_DOUBLE) {
            timings->vactive *= 2;
            dscan = 2;
      }

      switch (flags & ~FB_IGNOREMON) {
      case FB_MAXTIMINGS: /* maximize refresh rate */
            timings->hfreq = hfmax;
            fb_timings_hfreq(timings);
            if (timings->vfreq > vfmax) {
                  timings->vfreq = vfmax;
                  fb_timings_vfreq(timings);
            }
            if (timings->dclk > dclkmax) {
                  timings->dclk = dclkmax;
                  fb_timings_dclk(timings);
            }
            break;
      case FB_VSYNCTIMINGS: /* vrefresh driven */
            timings->vfreq = val;
            fb_timings_vfreq(timings);
            break;
      case FB_HSYNCTIMINGS: /* hsync driven */
            timings->hfreq = val;
            fb_timings_hfreq(timings);
            break;
      case FB_DCLKTIMINGS: /* pixelclock driven */
            timings->dclk = PICOS2KHZ(val) * 1000;
            fb_timings_dclk(timings);
            break;
      default:
            err = -EINVAL;
            
      } 
      
      if (err || (!(flags & FB_IGNOREMON) &&
          (timings->vfreq < vfmin || timings->vfreq > vfmax ||
           timings->hfreq < hfmin || timings->hfreq > hfmax ||
           timings->dclk < dclkmin || timings->dclk > dclkmax))) {
            err = -EINVAL;
      } else {
            var->pixclock = KHZ2PICOS(timings->dclk/1000);
            var->hsync_len = (timings->htotal * 8)/100;
            var->right_margin = (timings->hblank/2) - var->hsync_len;
            var->left_margin = timings->hblank - var->right_margin -
                  var->hsync_len;
            var->vsync_len = (3 * interlace)/dscan;
            var->lower_margin = (1 * interlace)/dscan;
            var->upper_margin = (timings->vblank * interlace)/dscan -
                  (var->vsync_len + var->lower_margin);
      }
      
      kfree(timings);
      return err;
}
#else
int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
{
      return 1;
}
void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
      specs = NULL;
}
void fb_destroy_modedb(struct fb_videomode *modedb)
{
}
int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var,
            struct fb_info *info)
{
      return -EINVAL;
}
#endif /* CONFIG_FB_MODE_HELPERS */
      
/*
 * fb_validate_mode - validates var against monitor capabilities
 * @var: pointer to fb_var_screeninfo
 * @info: pointer to fb_info
 *
 * DESCRIPTION:
 * Validates video mode against monitor capabilities specified in
 * info->monspecs.
 *
 * REQUIRES:
 * A valid info->monspecs.
 */
int fb_validate_mode(const struct fb_var_screeninfo *var, struct fb_info *info)
{
      u32 hfreq, vfreq, htotal, vtotal, pixclock;
      u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax;

      /* 
       * If monspecs are invalid, use values that are enough
       * for 640x480@60
       */
      if (!info->monspecs.hfmax || !info->monspecs.vfmax ||
          !info->monspecs.dclkmax ||
          info->monspecs.hfmax < info->monspecs.hfmin ||
          info->monspecs.vfmax < info->monspecs.vfmin ||
          info->monspecs.dclkmax < info->monspecs.dclkmin) {
            hfmin = 29000; hfmax = 30000;
            vfmin = 60; vfmax = 60;
            dclkmin = 0; dclkmax = 25000000;
      } else {
            hfmin = info->monspecs.hfmin;
            hfmax = info->monspecs.hfmax;
            vfmin = info->monspecs.vfmin;
            vfmax = info->monspecs.vfmax;
            dclkmin = info->monspecs.dclkmin;
            dclkmax = info->monspecs.dclkmax;
      }

      if (!var->pixclock)
            return -EINVAL;
      pixclock = PICOS2KHZ(var->pixclock) * 1000;
         
      htotal = var->xres + var->right_margin + var->hsync_len + 
            var->left_margin;
      vtotal = var->yres + var->lower_margin + var->vsync_len + 
            var->upper_margin;

      if (var->vmode & FB_VMODE_INTERLACED)
            vtotal /= 2;
      if (var->vmode & FB_VMODE_DOUBLE)
            vtotal *= 2;

      hfreq = pixclock/htotal;
      hfreq = (hfreq + 500) / 1000 * 1000;

      vfreq = hfreq/vtotal;

      return (vfreq < vfmin || vfreq > vfmax || 
            hfreq < hfmin || hfreq > hfmax ||
            pixclock < dclkmin || pixclock > dclkmax) ?
            -EINVAL : 0;
}

#if defined(CONFIG_FIRMWARE_EDID) && defined(CONFIG_X86)

/*
 * We need to ensure that the EDID block is only returned for
 * the primary graphics adapter.
 */

const unsigned char *fb_firmware_edid(struct device *device)
{
      struct pci_dev *dev = NULL;
      struct resource *res = NULL;
      unsigned char *edid = NULL;

      if (device)
            dev = to_pci_dev(device);

      if (dev)
            res = &dev->resource[PCI_ROM_RESOURCE];

      if (res && res->flags & IORESOURCE_ROM_SHADOW)
            edid = edid_info.dummy;

      return edid;
}
#else
const unsigned char *fb_firmware_edid(struct device *device)
{
      return NULL;
}
#endif
EXPORT_SYMBOL(fb_firmware_edid);

EXPORT_SYMBOL(fb_parse_edid);
EXPORT_SYMBOL(fb_edid_to_monspecs);
EXPORT_SYMBOL(fb_get_mode);
EXPORT_SYMBOL(fb_validate_mode);
EXPORT_SYMBOL(fb_destroy_modedb);

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