| 1 | /*
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| 2 | * Copyright 2005-2006 Luc Verhaegen.
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| 3 | *
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| 4 | * Permission is hereby granted, free of charge, to any person obtaining a
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| 5 | * copy of this software and associated documentation files (the "Software"),
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| 6 | * to deal in the Software without restriction, including without limitation
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| 7 | * the rights to use, copy, modify, merge, publish, distribute, sublicense,
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| 8 | * and/or sell copies of the Software, and to permit persons to whom the
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| 9 | * Software is furnished to do so, subject to the following conditions:
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| 10 | *
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| 11 | * The above copyright notice and this permission notice shall be included in
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| 12 | * all copies or substantial portions of the Software.
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| 13 | *
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| 14 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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| 15 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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| 16 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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| 17 | * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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| 18 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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| 19 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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| 20 | * OTHER DEALINGS IN THE SOFTWARE.
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| 21 | */
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| 22 |
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| 23 | /*
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| 24 | * The reason for having this function in a file of its own is
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| 25 | * so that ../utils/cvt/cvt can link to it, and that xf86CVTMode
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| 26 | * code is shared directly.
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| 27 | */
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| 28 |
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| 29 | #ifdef HAVE_XORG_CONFIG_H
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| 30 | #include <xorg-config.h>
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| 31 | #else
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| 32 | #ifdef HAVE_CONFIG_H
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| 33 | #include <config.h>
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| 34 | #endif
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| 35 | #endif
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| 36 |
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| 37 | #include "xf86.h"
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| 38 | #include "xf86Modes.h"
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| 39 |
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| 40 | #include <string.h>
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| 41 |
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| 42 | /*
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| 43 | * Generate a CVT standard mode from HDisplay, VDisplay and VRefresh.
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| 44 | *
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| 45 | * These calculations are stolen from the CVT calculation spreadsheet written
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| 46 | * by Graham Loveridge. He seems to be claiming no copyright and there seems to
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| 47 | * be no license attached to this. He apparently just wants to see his name
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| 48 | * mentioned.
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| 49 | *
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| 50 | * This file can be found at http://www.vesa.org/Public/CVT/CVTd6r1.xls
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| 51 | *
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| 52 | * Comments and structure corresponds to the comments and structure of the xls.
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| 53 | * This should ease importing of future changes to the standard (not very
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| 54 | * likely though).
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| 55 | *
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| 56 | * About margins; i'm sure that they are to be the bit between HDisplay and
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| 57 | * HBlankStart, HBlankEnd and HTotal, VDisplay and VBlankStart, VBlankEnd and
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| 58 | * VTotal, where the overscan colour is shown. FB seems to call _all_ blanking
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| 59 | * outside sync "margin" for some reason. Since we prefer seeing proper
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| 60 | * blanking instead of the overscan colour, and since the Crtc* values will
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| 61 | * probably get altered after us, we will disable margins altogether. With
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| 62 | * these calculations, Margins will plainly expand H/VDisplay, and we don't
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| 63 | * want that. -- libv
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| 64 | *
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| 65 | */
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| 66 | DisplayModePtr
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| 67 | xf86CVTMode(int HDisplay, int VDisplay, float VRefresh, Bool Reduced,
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| 68 | Bool Interlaced)
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| 69 | {
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| 70 | DisplayModeRec *Mode = xnfcalloc(1, sizeof(DisplayModeRec));
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| 71 |
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| 72 | /* 1) top/bottom margin size (% of height) - default: 1.8 */
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| 73 | #define CVT_MARGIN_PERCENTAGE 1.8
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| 74 |
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| 75 | /* 2) character cell horizontal granularity (pixels) - default 8 */
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| 76 | #define CVT_H_GRANULARITY 8
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| 77 |
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| 78 | /* 4) Minimum vertical porch (lines) - default 3 */
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| 79 | #define CVT_MIN_V_PORCH 3
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| 80 |
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| 81 | /* 4) Minimum number of vertical back porch lines - default 6 */
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| 82 | #define CVT_MIN_V_BPORCH 6
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| 83 |
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| 84 | /* Pixel Clock step (kHz) */
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| 85 | #define CVT_CLOCK_STEP 250
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| 86 |
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| 87 | Bool Margins = FALSE;
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| 88 | float VFieldRate, HPeriod;
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| 89 | int HDisplayRnd, HMargin;
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| 90 | int VDisplayRnd, VMargin, VSync;
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| 91 | float Interlace; /* Please rename this */
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| 92 | char *tmp;
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| 93 |
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| 94 | /* CVT default is 60.0Hz */
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| 95 | if (!VRefresh)
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| 96 | VRefresh = 60.0;
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| 97 |
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| 98 | /* 1. Required field rate */
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| 99 | if (Interlaced)
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| 100 | VFieldRate = VRefresh * 2;
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| 101 | else
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| 102 | VFieldRate = VRefresh;
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| 103 |
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| 104 | /* 2. Horizontal pixels */
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| 105 | HDisplayRnd = HDisplay - (HDisplay % CVT_H_GRANULARITY);
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| 106 |
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| 107 | /* 3. Determine left and right borders */
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| 108 | if (Margins) {
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| 109 | /* right margin is actually exactly the same as left */
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| 110 | HMargin = (((float) HDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0);
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| 111 | HMargin -= HMargin % CVT_H_GRANULARITY;
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| 112 | }
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| 113 | else
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| 114 | HMargin = 0;
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| 115 |
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| 116 | /* 4. Find total active pixels */
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| 117 | Mode->HDisplay = HDisplayRnd + 2 * HMargin;
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| 118 |
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| 119 | /* 5. Find number of lines per field */
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| 120 | if (Interlaced)
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| 121 | VDisplayRnd = VDisplay / 2;
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| 122 | else
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| 123 | VDisplayRnd = VDisplay;
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| 124 |
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| 125 | /* 6. Find top and bottom margins */
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| 126 | /* nope. */
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| 127 | if (Margins)
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| 128 | /* top and bottom margins are equal again. */
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| 129 | VMargin = (((float) VDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0);
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| 130 | else
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| 131 | VMargin = 0;
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| 132 |
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| 133 | Mode->VDisplay = VDisplay + 2 * VMargin;
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| 134 |
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| 135 | /* 7. Interlace */
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| 136 | if (Interlaced)
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| 137 | Interlace = 0.5;
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| 138 | else
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| 139 | Interlace = 0.0;
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| 140 |
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| 141 | /* Determine VSync Width from aspect ratio */
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| 142 | if (!(VDisplay % 3) && ((VDisplay * 4 / 3) == HDisplay))
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| 143 | VSync = 4;
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| 144 | else if (!(VDisplay % 9) && ((VDisplay * 16 / 9) == HDisplay))
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| 145 | VSync = 5;
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| 146 | else if (!(VDisplay % 10) && ((VDisplay * 16 / 10) == HDisplay))
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| 147 | VSync = 6;
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| 148 | else if (!(VDisplay % 4) && ((VDisplay * 5 / 4) == HDisplay))
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| 149 | VSync = 7;
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| 150 | else if (!(VDisplay % 9) && ((VDisplay * 15 / 9) == HDisplay))
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| 151 | VSync = 7;
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| 152 | else /* Custom */
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| 153 | VSync = 10;
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| 154 |
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| 155 | if (!Reduced) { /* simplified GTF calculation */
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| 156 |
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| 157 | /* 4) Minimum time of vertical sync + back porch interval (µs)
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| 158 | * default 550.0 */
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| 159 | #define CVT_MIN_VSYNC_BP 550.0
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| 160 |
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| 161 | /* 3) Nominal HSync width (% of line period) - default 8 */
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| 162 | #define CVT_HSYNC_PERCENTAGE 8
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| 163 |
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| 164 | float HBlankPercentage;
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| 165 | int VSyncAndBackPorch, VBackPorch;
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| 166 | int HBlank;
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| 167 |
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| 168 | /* 8. Estimated Horizontal period */
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| 169 | HPeriod = ((float) (1000000.0 / VFieldRate - CVT_MIN_VSYNC_BP)) /
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| 170 | (VDisplayRnd + 2 * VMargin + CVT_MIN_V_PORCH + Interlace);
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| 171 |
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| 172 | /* 9. Find number of lines in sync + backporch */
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| 173 | if (((int) (CVT_MIN_VSYNC_BP / HPeriod) + 1) <
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| 174 | (VSync + CVT_MIN_V_PORCH))
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| 175 | VSyncAndBackPorch = VSync + CVT_MIN_V_PORCH;
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| 176 | else
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| 177 | VSyncAndBackPorch = (int) (CVT_MIN_VSYNC_BP / HPeriod) + 1;
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| 178 |
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| 179 | /* 10. Find number of lines in back porch */
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| 180 | VBackPorch = VSyncAndBackPorch - VSync;
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| 181 | (void) VBackPorch;
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| 182 |
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| 183 | /* 11. Find total number of lines in vertical field */
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| 184 | Mode->VTotal = VDisplayRnd + 2 * VMargin + VSyncAndBackPorch + Interlace
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| 185 | + CVT_MIN_V_PORCH;
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| 186 |
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| 187 | /* 5) Definition of Horizontal blanking time limitation */
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| 188 | /* Gradient (%/kHz) - default 600 */
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| 189 | #define CVT_M_FACTOR 600
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| 190 |
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| 191 | /* Offset (%) - default 40 */
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| 192 | #define CVT_C_FACTOR 40
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| 193 |
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| 194 | /* Blanking time scaling factor - default 128 */
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| 195 | #define CVT_K_FACTOR 128
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| 196 |
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| 197 | /* Scaling factor weighting - default 20 */
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| 198 | #define CVT_J_FACTOR 20
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| 199 |
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| 200 | #define CVT_M_PRIME CVT_M_FACTOR * CVT_K_FACTOR / 256
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| 201 | #define CVT_C_PRIME (CVT_C_FACTOR - CVT_J_FACTOR) * CVT_K_FACTOR / 256 + \
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| 202 | CVT_J_FACTOR
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| 203 |
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| 204 | /* 12. Find ideal blanking duty cycle from formula */
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| 205 | HBlankPercentage = CVT_C_PRIME - CVT_M_PRIME * HPeriod / 1000.0;
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| 206 |
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| 207 | /* 13. Blanking time */
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| 208 | if (HBlankPercentage < 20)
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| 209 | HBlankPercentage = 20;
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| 210 |
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| 211 | HBlank = Mode->HDisplay * HBlankPercentage / (100.0 - HBlankPercentage);
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| 212 | HBlank -= HBlank % (2 * CVT_H_GRANULARITY);
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| 213 |
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| 214 | /* 14. Find total number of pixels in a line. */
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| 215 | Mode->HTotal = Mode->HDisplay + HBlank;
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| 216 |
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| 217 | /* Fill in HSync values */
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| 218 | Mode->HSyncEnd = Mode->HDisplay + HBlank / 2;
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| 219 |
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| 220 | Mode->HSyncStart = Mode->HSyncEnd -
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| 221 | (Mode->HTotal * CVT_HSYNC_PERCENTAGE) / 100;
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| 222 | Mode->HSyncStart += CVT_H_GRANULARITY -
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| 223 | Mode->HSyncStart % CVT_H_GRANULARITY;
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| 224 |
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| 225 | /* Fill in VSync values */
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| 226 | Mode->VSyncStart = Mode->VDisplay + CVT_MIN_V_PORCH;
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| 227 | Mode->VSyncEnd = Mode->VSyncStart + VSync;
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| 228 |
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| 229 | }
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| 230 | else { /* Reduced blanking */
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| 231 | /* Minimum vertical blanking interval time (µs) - default 460 */
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| 232 | #define CVT_RB_MIN_VBLANK 460.0
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| 233 |
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| 234 | /* Fixed number of clocks for horizontal sync */
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| 235 | #define CVT_RB_H_SYNC 32.0
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| 236 |
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| 237 | /* Fixed number of clocks for horizontal blanking */
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| 238 | #define CVT_RB_H_BLANK 160.0
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| 239 |
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| 240 | /* Fixed number of lines for vertical front porch - default 3 */
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| 241 | #define CVT_RB_VFPORCH 3
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| 242 |
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| 243 | int VBILines;
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| 244 |
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| 245 | /* 8. Estimate Horizontal period. */
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| 246 | HPeriod = ((float) (1000000.0 / VFieldRate - CVT_RB_MIN_VBLANK)) /
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| 247 | (VDisplayRnd + 2 * VMargin);
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| 248 |
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| 249 | /* 9. Find number of lines in vertical blanking */
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| 250 | VBILines = ((float) CVT_RB_MIN_VBLANK) / HPeriod + 1;
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| 251 |
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| 252 | /* 10. Check if vertical blanking is sufficient */
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| 253 | if (VBILines < (CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH))
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| 254 | VBILines = CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH;
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| 255 |
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| 256 | /* 11. Find total number of lines in vertical field */
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| 257 | Mode->VTotal = VDisplayRnd + 2 * VMargin + Interlace + VBILines;
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| 258 |
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| 259 | /* 12. Find total number of pixels in a line */
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| 260 | Mode->HTotal = Mode->HDisplay + CVT_RB_H_BLANK;
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| 261 |
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| 262 | /* Fill in HSync values */
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| 263 | Mode->HSyncEnd = Mode->HDisplay + CVT_RB_H_BLANK / 2;
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| 264 | Mode->HSyncStart = Mode->HSyncEnd - CVT_RB_H_SYNC;
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| 265 |
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| 266 | /* Fill in VSync values */
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| 267 | Mode->VSyncStart = Mode->VDisplay + CVT_RB_VFPORCH;
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| 268 | Mode->VSyncEnd = Mode->VSyncStart + VSync;
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| 269 | }
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| 270 |
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| 271 | /* 15/13. Find pixel clock frequency (kHz for xf86) */
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| 272 | Mode->Clock = Mode->HTotal * 1000.0 / HPeriod;
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| 273 | Mode->Clock -= Mode->Clock % CVT_CLOCK_STEP;
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| 274 |
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| 275 | /* 16/14. Find actual Horizontal Frequency (kHz) */
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| 276 | Mode->HSync = ((float) Mode->Clock) / ((float) Mode->HTotal);
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| 277 |
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| 278 | /* 17/15. Find actual Field rate */
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| 279 | Mode->VRefresh = (1000.0 * ((float) Mode->Clock)) /
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| 280 | ((float) (Mode->HTotal * Mode->VTotal));
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| 281 |
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| 282 | /* 18/16. Find actual vertical frame frequency */
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| 283 | /* ignore - just set the mode flag for interlaced */
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| 284 | if (Interlaced)
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| 285 | Mode->VTotal *= 2;
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| 286 |
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| 287 | XNFasprintf(&tmp, "%dx%d", HDisplay, VDisplay);
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| 288 | Mode->name = tmp;
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| 289 |
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| 290 | if (Reduced)
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| 291 | Mode->Flags |= V_PHSYNC | V_NVSYNC;
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| 292 | else
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| 293 | Mode->Flags |= V_NHSYNC | V_PVSYNC;
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| 294 |
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| 295 | if (Interlaced)
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| 296 | Mode->Flags |= V_INTERLACE;
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| 297 |
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| 298 | return Mode;
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| 299 | }
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