edid-parse.c

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/*
 * Copyright 2007 Red Hat, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/* Author: Soren Sandmann <sandmann@redhat.com> */

#include "edid.h"
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <stdio.h>

#define TRUE 1
#define FALSE 0

static int
get_bit (int in, int bit)
{
    return (in & (1 << bit)) >> bit;
}

static int
get_bits (int in, int begin, int end)
{
    int mask = (1 << (end - begin + 1)) - 1;
    
    return (in >> begin) & mask;
}

static int
decode_header (const uchar *edid)
{
    if (memcmp (edid, "\x00\xff\xff\xff\xff\xff\xff\x00", 8) == 0)
  return TRUE;
    return FALSE;
}

static int
decode_vendor_and_product_identification (const uchar *edid, MonitorInfo *info)
{
    int is_model_year;
    
    /* Manufacturer Code */
    info->manufacturer_code[0]  = get_bits (edid[0x08], 2, 6);
    info->manufacturer_code[1]  = get_bits (edid[0x08], 0, 1) << 3;
    info->manufacturer_code[1] |= get_bits (edid[0x09], 5, 7);
    info->manufacturer_code[2]  = get_bits (edid[0x09], 0, 4);
    info->manufacturer_code[3]  = '\0';
    
    info->manufacturer_code[0] += 'A' - 1;
    info->manufacturer_code[1] += 'A' - 1;
    info->manufacturer_code[2] += 'A' - 1;

    /* Product Code */
    info->product_code = edid[0x0b] << 8 | edid[0x0a];

    /* Serial Number */
    info->serial_number =
  edid[0x0c] | edid[0x0d] << 8 | edid[0x0e] << 16 | edid[0x0f] << 24;

    /* Week and Year */
    is_model_year = FALSE;
    switch (edid[0x10])
    {
    case 0x00:
  info->production_week = -1;
  break;

    case 0xff:
  info->production_week = -1;
  is_model_year = TRUE;
  break;

    default:
  info->production_week = edid[0x10];
  break;
    }

    if (is_model_year)
    {
  info->production_year = -1;
  info->model_year = 1990 + edid[0x11];
    }
    else
    {
  info->production_year = 1990 + edid[0x11];
  info->model_year = -1;
    }

    return TRUE;
}

static int
decode_edid_version (const uchar *edid, MonitorInfo *info)
{
    info->major_version = edid[0x12];
    info->minor_version = edid[0x13];

    return TRUE;
}

static int
decode_display_parameters (const uchar *edid, MonitorInfo *info)
{
    /* Digital vs Analog */
    info->is_digital = get_bit (edid[0x14], 7);

    if (info->is_digital)
    {
  int bits;
  
  static const int bit_depth[8] =
  {
      -1, 6, 8, 10, 12, 14, 16, -1
  };

  static const Interface interfaces[6] =
  {
      UNDEFINED, DVI, HDMI_A, HDMI_B, MDDI, DISPLAY_PORT
  };

  bits = get_bits (edid[0x14], 4, 6);
  info->digital.bits_per_primary = bit_depth[bits];

  bits = get_bits (edid[0x14], 0, 3);
  
  if (bits <= 5)
      info->digital.interface = interfaces[bits];
  else
      info->digital.interface = UNDEFINED;
    }
    else
    {
  int bits = get_bits (edid[0x14], 5, 6);
  
  static const double levels[][3] =
  {
      { 0.7,   0.3,    1.0 },
      { 0.714, 0.286,  1.0 },
      { 1.0,   0.4,    1.4 },
      { 0.7,   0.0,    0.7 },
  };

  info->analog.video_signal_level = levels[bits][0];
  info->analog.sync_signal_level = levels[bits][1];
  info->analog.total_signal_level = levels[bits][2];

  info->analog.blank_to_black = get_bit (edid[0x14], 4);

  info->analog.separate_hv_sync = get_bit (edid[0x14], 3);
  info->analog.composite_sync_on_h = get_bit (edid[0x14], 2);
  info->analog.composite_sync_on_green = get_bit (edid[0x14], 1);

  info->analog.serration_on_vsync = get_bit (edid[0x14], 0);
    }

    /* Screen Size / Aspect Ratio */
    if (edid[0x15] == 0 && edid[0x16] == 0)
    {
  info->width_mm = -1;
  info->height_mm = -1;
  info->aspect_ratio = -1.0;
    }
    else if (edid[0x16] == 0)
    {
  info->width_mm = -1;
  info->height_mm = -1; 
  info->aspect_ratio = 100.0 / (edid[0x15] + 99);
    }
    else if (edid[0x15] == 0)
    {
  info->width_mm = -1;
  info->height_mm = -1;
  info->aspect_ratio = 100.0 / (edid[0x16] + 99);
  info->aspect_ratio = 1/info->aspect_ratio; /* portrait */
    }
    else
    {
  info->width_mm = 10 * edid[0x15];
  info->height_mm = 10 * edid[0x16];
    }

    /* Gamma */
    if (edid[0x17] == 0xFF)
  info->gamma = -1.0;
    else
  info->gamma = (edid[0x17] + 100.0) / 100.0;

    /* Features */
    info->standby = get_bit (edid[0x18], 7);
    info->suspend = get_bit (edid[0x18], 6);
    info->active_off = get_bit (edid[0x18], 5);

    if (info->is_digital)
    {
  info->digital.rgb444 = TRUE;
  if (get_bit (edid[0x18], 3))
      info->digital.ycrcb444 = 1;
  if (get_bit (edid[0x18], 4))
      info->digital.ycrcb422 = 1;
    }
    else
    {
  int bits = get_bits (edid[0x18], 3, 4);
  ColorType color_type[4] =
  {
      MONOCHROME, RGB, OTHER_COLOR, UNDEFINED_COLOR
  };

  info->analog.color_type = color_type[bits];
    }

    info->srgb_is_standard = get_bit (edid[0x18], 2);

    /* In 1.3 this is called "has preferred timing" */
    info->preferred_timing_includes_native = get_bit (edid[0x18], 1);

    /* FIXME: In 1.3 this indicates whether the monitor accepts GTF */
    info->continuous_frequency = get_bit (edid[0x18], 0);
    return TRUE;
}

static double
decode_fraction (int high, int low)
{
    double result = 0.0;
    int i;

    high = (high << 2) | low;

    for (i = 0; i < 10; ++i)
  result += get_bit (high, i) * pow (2, i - 10);

    return result;
}

static int
decode_color_characteristics (const uchar *edid, MonitorInfo *info)
{
    info->red_x = decode_fraction (edid[0x1b], get_bits (edid[0x19], 6, 7));
    info->red_y = decode_fraction (edid[0x1c], get_bits (edid[0x19], 5, 4));
    info->green_x = decode_fraction (edid[0x1d], get_bits (edid[0x19], 2, 3));
    info->green_y = decode_fraction (edid[0x1e], get_bits (edid[0x19], 0, 1));
    info->blue_x = decode_fraction (edid[0x1f], get_bits (edid[0x1a], 6, 7));
    info->blue_y = decode_fraction (edid[0x20], get_bits (edid[0x1a], 4, 5));
    info->white_x = decode_fraction (edid[0x21], get_bits (edid[0x1a], 2, 3));
    info->white_y = decode_fraction (edid[0x22], get_bits (edid[0x1a], 0, 1));

    return TRUE;
}

static int
decode_established_timings (const uchar *edid, MonitorInfo *info)
{
    static const Timing established[][8] = 
    {
  {
      { 800, 600, 60 },
      { 800, 600, 56 },
      { 640, 480, 75 },
      { 640, 480, 72 },
      { 640, 480, 67 },
      { 640, 480, 60 },
      { 720, 400, 88 },
      { 720, 400, 70 }
  },
  {
      { 1280, 1024, 75 },
      { 1024, 768, 75 },
      { 1024, 768, 70 },
      { 1024, 768, 60 },
      { 1024, 768, 87 },
      { 832, 624, 75 },
      { 800, 600, 75 },
      { 800, 600, 72 }
  },
  {
      { 0, 0, 0 },
      { 0, 0, 0 },
      { 0, 0, 0 },
      { 0, 0, 0 },
      { 0, 0, 0 },
      { 0, 0, 0 },
      { 0, 0, 0 },
      { 1152, 870, 75 }
  },
    };

    int i, j, idx;

    idx = 0;
    for (i = 0; i < 3; ++i)
    {
  for (j = 0; j < 8; ++j)
  {
      int byte = edid[0x23 + i];

      if (get_bit (byte, j) && established[i][j].frequency != 0)
    info->established[idx++] = established[i][j];
  }
    }
    return TRUE;
}

static int
decode_standard_timings (const uchar *edid, MonitorInfo *info)
{
    int i;
    
    for (i = 0; i < 8; i++)
    {
  int first = edid[0x26 + 2 * i];
  int second = edid[0x27 + 2 * i];

  if (first != 0x01 && second != 0x01)
  {
      int w = 8 * (first + 31);
      int h = 0;

      switch (get_bits (second, 6, 7))
      {
      case 0x00: h = (w / 16) * 10; break;
      case 0x01: h = (w / 4) * 3; break;
      case 0x02: h = (w / 5) * 4; break;
      case 0x03: h = (w / 16) * 9; break;
      }

      info->standard[i].width = w;
      info->standard[i].height = h;
      info->standard[i].frequency = get_bits (second, 0, 5) + 60;
  }
    }
    
    return TRUE;
}

static void
decode_lf_string (const uchar *s, int n_chars, char *result)
{
    int i;
    for (i = 0; i < n_chars; ++i)
    {
  if (s[i] == 0x0a)
  {
      *result++ = '\0';
      break;
  }
  else if (s[i] == 0x00)
  {
      /* Convert embedded 0's to spaces */
      *result++ = ' ';
  }
  else
  {
      *result++ = s[i];
  }
    }
}

static void
decode_display_descriptor (const uchar *desc,
         MonitorInfo *info)
{
    switch (desc[0x03])
    {
    case 0xFC:
  decode_lf_string (desc + 5, 13, info->dsc_product_name);
  break;
    case 0xFF:
  decode_lf_string (desc + 5, 13, info->dsc_serial_number);
  break;
    case 0xFE:
  decode_lf_string (desc + 5, 13, info->dsc_string);
  break;
    case 0xFD:
  /* Range Limits */
  break;
    case 0xFB:
  /* Color Point */
  break;
    case 0xFA:
  /* Timing Identifications */
  break;
    case 0xF9:
  /* Color Management */
  break;
    case 0xF8:
  /* Timing Codes */
  break;
    case 0xF7:
  /* Established Timings */
  break;
    case 0x10:
  break;
    }
}

static void
decode_detailed_timing (const uchar *timing,
      DetailedTiming *detailed)
{
    int bits;
    StereoType stereo[] =
    {
  NO_STEREO, NO_STEREO, FIELD_RIGHT, FIELD_LEFT,
  TWO_WAY_RIGHT_ON_EVEN, TWO_WAY_LEFT_ON_EVEN,
  FOUR_WAY_INTERLEAVED, SIDE_BY_SIDE
    };
    
    detailed->pixel_clock = (timing[0x00] | timing[0x01] << 8) * 10000;
    detailed->h_addr = timing[0x02] | ((timing[0x04] & 0xf0) << 4);
    detailed->h_blank = timing[0x03] | ((timing[0x04] & 0x0f) << 8);
    detailed->v_addr = timing[0x05] | ((timing[0x07] & 0xf0) << 4);
    detailed->v_blank = timing[0x06] | ((timing[0x07] & 0x0f) << 8);
    detailed->h_front_porch = timing[0x08] | get_bits (timing[0x0b], 6, 7) << 8;
    detailed->h_sync = timing[0x09] | get_bits (timing[0x0b], 4, 5) << 8;
    detailed->v_front_porch =
  get_bits (timing[0x0a], 4, 7) | get_bits (timing[0x0b], 2, 3) << 4;
    detailed->v_sync =
  get_bits (timing[0x0a], 0, 3) | get_bits (timing[0x0b], 0, 1) << 4;
    detailed->width_mm =  timing[0x0c] | get_bits (timing[0x0e], 4, 7) << 8;
    detailed->height_mm = timing[0x0d] | get_bits (timing[0x0e], 0, 3) << 8;
    detailed->right_border = timing[0x0f];
    detailed->top_border = timing[0x10];

    detailed->interlaced = get_bit (timing[0x11], 7);

    /* Stereo */
    bits = get_bits (timing[0x11], 5, 6) << 1 | get_bit (timing[0x11], 0);
    detailed->stereo = stereo[bits];

    /* Sync */
    bits = timing[0x11];

    detailed->digital_sync = get_bit (bits, 4);
    if (detailed->digital_sync)
    {
  detailed->digital.composite = !get_bit (bits, 3);

  if (detailed->digital.composite)
  {
      detailed->digital.serrations = get_bit (bits, 2);
      detailed->digital.negative_vsync = FALSE;
  }
  else
  {
      detailed->digital.serrations = FALSE;
      detailed->digital.negative_vsync = !get_bit (bits, 2);
  }

  detailed->digital.negative_hsync = !get_bit (bits, 0);
    }
    else
    {
  detailed->analog.bipolar = get_bit (bits, 3);
  detailed->analog.serrations = get_bit (bits, 2);
  detailed->analog.sync_on_green = !get_bit (bits, 1);
    }
}

static int
decode_descriptors (const uchar *edid, MonitorInfo *info)
{
    int i;
    int timing_idx;
    
    timing_idx = 0;
    
    for (i = 0; i < 4; ++i)
    {
  int index = 0x36 + i * 18;

  if (edid[index + 0] == 0x00 && edid[index + 1] == 0x00)
  {
      decode_display_descriptor (edid + index, info);
  }
  else
  {
      decode_detailed_timing (
    edid + index, &(info->detailed_timings[timing_idx++]));
  }
    }

    info->n_detailed_timings = timing_idx;

    return TRUE;
}

static void
decode_check_sum (const uchar *edid,
      MonitorInfo *info)
{
    int i;
    uchar check = 0;

    for (i = 0; i < 128; ++i)
  check += edid[i];

    info->checksum = check;
}

MonitorInfo *
decode_edid (const uchar *edid)
{
    MonitorInfo *info = calloc (1, sizeof (MonitorInfo));

    decode_check_sum (edid, info);
    
    if (!decode_header (edid) ||
        !decode_vendor_and_product_identification (edid, info) ||
        !decode_edid_version (edid, info) ||
        !decode_display_parameters (edid, info) ||
        !decode_color_characteristics (edid, info) ||
        !decode_established_timings (edid, info) ||
        !decode_standard_timings (edid, info) ||
        !decode_descriptors (edid, info)) {
        free(info);
  return NULL;
    }
    
    return info;
}

static const char *
yesno (int v)
{
    return v? "yes" : "no";
}

void
dump_monitor_info (MonitorInfo *info)
{
    char *s;
    int i;
    
    printf ("Checksum: %d (%s)\n",
      info->checksum, info->checksum? "incorrect" : "correct");
    printf ("Manufacturer Code: %s\n", info->manufacturer_code);
    printf ("Product Code: 0x%x\n", info->product_code);
    printf ("Serial Number: %u\n", info->serial_number);
    
    if (info->production_week != -1)
  printf ("Production Week: %d\n", info->production_week);
    else
  printf ("Production Week: unspecified\n");
    
    if (info->production_year != -1)
  printf ("Production Year: %d\n", info->production_year);
    else
  printf ("Production Year: unspecified\n");
    
    if (info->model_year != -1)
  printf ("Model Year: %d\n", info->model_year);
    else
  printf ("Model Year: unspecified\n");
    
    printf ("EDID revision: %d.%d\n", info->major_version, info->minor_version);
    
    printf ("Display is %s\n", info->is_digital? "digital" : "analog");
    if (info->is_digital)
    {
  const char *interface;
  if (info->digital.bits_per_primary != -1)
      printf ("Bits Per Primary: %d\n", info->digital.bits_per_primary);
  else
      printf ("Bits Per Primary: undefined\n");
  
  switch (info->digital.interface)
  {
  case DVI: interface = "DVI"; break;
  case HDMI_A: interface = "HDMI-a"; break;
  case HDMI_B: interface = "HDMI-b"; break;
  case MDDI: interface = "MDDI"; break;
  case DISPLAY_PORT: interface = "DisplayPort"; break;
  case UNDEFINED: interface = "undefined"; break;
  default: interface = "unknown"; break;
  }
  printf ("Interface: %s\n", interface);
  
  printf ("RGB 4:4:4: %s\n", yesno (info->digital.rgb444));
  printf ("YCrCb 4:4:4: %s\n", yesno (info->digital.ycrcb444));
  printf ("YCrCb 4:2:2: %s\n", yesno (info->digital.ycrcb422));
    }
    else
    {
  printf ("Video Signal Level: %f\n", info->analog.video_signal_level);
  printf ("Sync Signal Level: %f\n", info->analog.sync_signal_level);
  printf ("Total Signal Level: %f\n", info->analog.total_signal_level);
  
  printf ("Blank to Black: %s\n",
    yesno (info->analog.blank_to_black));
  printf ("Separate HV Sync: %s\n",
    yesno (info->analog.separate_hv_sync));
  printf ("Composite Sync on H: %s\n",
    yesno (info->analog.composite_sync_on_h));
  printf ("Serration on VSync: %s\n",
    yesno (info->analog.serration_on_vsync));
  
  switch (info->analog.color_type)
  {
  case UNDEFINED_COLOR: s = "undefined"; break;
  case MONOCHROME: s = "monochrome"; break;
  case RGB: s = "rgb"; break;
  case OTHER_COLOR: s = "other color"; break;
  default: s = "unknown"; break;
  };
  
  printf ("Color: %s\n", s);
    }
    
    if (info->width_mm == -1)
  printf ("Width: undefined\n");
    else
  printf ("Width: %d mm\n", info->width_mm);
    
    if (info->height_mm == -1)
  printf ("Height: undefined\n");
    else
  printf ("Height: %d mm\n", info->height_mm);
    
    if (info->aspect_ratio > 0)
  printf ("Aspect Ratio: %f\n", info->aspect_ratio);
    else
  printf ("Aspect Ratio: undefined\n");
    
    if (info->gamma >= 0)
  printf ("Gamma: %f\n", info->gamma);
    else
  printf ("Gamma: undefined\n");
    
    printf ("Standby: %s\n", yesno (info->standby));
    printf ("Suspend: %s\n", yesno (info->suspend));
    printf ("Active Off: %s\n", yesno (info->active_off));
    
    printf ("SRGB is Standard: %s\n", yesno (info->srgb_is_standard));
    printf ("Preferred Timing Includes Native: %s\n",
      yesno (info->preferred_timing_includes_native));
    printf ("Continuous Frequency: %s\n", yesno (info->continuous_frequency));
    
    printf ("Red X: %f\n", info->red_x);
    printf ("Red Y: %f\n", info->red_y);
    printf ("Green X: %f\n", info->green_x);
    printf ("Green Y: %f\n", info->green_y);
    printf ("Blue X: %f\n", info->blue_x);
    printf ("Blue Y: %f\n", info->blue_y);
    printf ("White X: %f\n", info->white_x);
    printf ("White Y: %f\n", info->white_y);
    
    printf ("Established Timings:\n");
    
    for (i = 0; i < 24; ++i)
    {
  Timing *timing = &(info->established[i]);
  
  if (timing->frequency == 0)
      break;
  
  printf ("  %d x %d @ %d Hz\n",
    timing->width, timing->height, timing->frequency);
  
    }
    
    printf ("Standard Timings:\n");
    for (i = 0; i < 8; ++i)
    {
  Timing *timing = &(info->standard[i]);
  
  if (timing->frequency == 0)
      break;
  
  printf ("  %d x %d @ %d Hz\n",
    timing->width, timing->height, timing->frequency);
    }
    
    for (i = 0; i < info->n_detailed_timings; ++i)
    {
  DetailedTiming *timing = &(info->detailed_timings[i]);
  const char *s;
  
  printf ("Timing%s: \n",
    (i == 0 && info->preferred_timing_includes_native)?
    " (Preferred)" : "");
  printf ("  Pixel Clock: %d\n", timing->pixel_clock);
  printf ("  H Addressable: %d\n", timing->h_addr);
  printf ("  H Blank: %d\n", timing->h_blank);
  printf ("  H Front Porch: %d\n", timing->h_front_porch);
  printf ("  H Sync: %d\n", timing->h_sync);
  printf ("  V Addressable: %d\n", timing->v_addr);
  printf ("  V Blank: %d\n", timing->v_blank);
  printf ("  V Front Porch: %d\n", timing->v_front_porch);
  printf ("  V Sync: %d\n", timing->v_sync);
  printf ("  Width: %d mm\n", timing->width_mm);
  printf ("  Height: %d mm\n", timing->height_mm);
  printf ("  Right Border: %d\n", timing->right_border);
  printf ("  Top Border: %d\n", timing->top_border);
  switch (timing->stereo)
  {
  default:
  case NO_STEREO:   s = "No Stereo"; break;
  case FIELD_RIGHT: s = "Field Sequential, Right on Sync"; break;
  case FIELD_LEFT:  s = "Field Sequential, Left on Sync"; break;
  case TWO_WAY_RIGHT_ON_EVEN: s = "Two-way, Right on Even"; break;
  case TWO_WAY_LEFT_ON_EVEN:  s = "Two-way, Left on Even"; break;
  case FOUR_WAY_INTERLEAVED:  s = "Four-way Interleaved"; break;
  case SIDE_BY_SIDE:          s = "Side-by-Side"; break;
  }
  printf ("  Stereo: %s\n", s);
  
  if (timing->digital_sync)
  {
      printf ("  Digital Sync:\n");
      printf ("    composite: %s\n", yesno (timing->digital.composite));
      printf ("    serrations: %s\n", yesno (timing->digital.serrations));
      printf ("    negative vsync: %s\n",
        yesno (timing->digital.negative_vsync));
      printf ("    negative hsync: %s\n",
        yesno (timing->digital.negative_hsync));
  }
  else
  {
      printf ("  Analog Sync:\n");
      printf ("    bipolar: %s\n", yesno (timing->analog.bipolar));
      printf ("    serrations: %s\n", yesno (timing->analog.serrations));
      printf ("    sync on green: %s\n", yesno (
      timing->analog.sync_on_green));
  }
    }
    
    printf ("Detailed Product information:\n");
    printf ("  Product Name: %s\n", info->dsc_product_name);
    printf ("  Serial Number: %s\n", info->dsc_serial_number);
    printf ("  Unspecified String: %s\n", info->dsc_string);
}