| 1 | /* $Id: display-svga-xf86cvt.cpp 98202 2023-01-22 02:05:53Z vboxsync $ */
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| 2 | /** @file
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| 3 | * Guest Additions - Our version of xf86CVTMode.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2006-2023 Oracle and/or its affiliates.
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| 8 | * This file is based on x.org server 1.18.0 file xf86cvt.c:
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| 9 | *
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| 10 | * Copyright 2005-2006 Luc Verhaegen.
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| 11 | *
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| 12 | * Permission is hereby granted, free of charge, to any person obtaining a
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| 13 | * copy of this software and associated documentation files (the "Software"),
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| 14 | * to deal in the Software without restriction, including without limitation
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| 15 | * the rights to use, copy, modify, merge, publish, distribute, sublicense,
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| 16 | * and/or sell copies of the Software, and to permit persons to whom the
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| 17 | * Software is furnished to do so, subject to the following conditions:
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| 18 | *
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| 19 | * The above copyright notice and this permission notice shall be included in
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| 20 | * all copies or substantial portions of the Software.
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| 21 | *
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| 22 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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| 23 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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| 24 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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| 25 | * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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| 26 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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| 27 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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| 28 | * OTHER DEALINGS IN THE SOFTWARE.
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| 29 | */
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| 30 |
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| 31 | #if 0
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| 32 | /*
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| 33 | * The reason for having this function in a file of its own is
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| 34 | * so that ../utils/cvt/cvt can link to it, and that xf86CVTMode
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| 35 | * code is shared directly.
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| 36 | */
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| 37 |
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| 38 | #ifdef HAVE_XORG_CONFIG_H
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| 39 | #include <xorg-config.h>
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| 40 | #else
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| 41 | #ifdef HAVE_CONFIG_H
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| 42 | #include <config.h>
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| 43 | #endif
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| 44 | #endif
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| 45 |
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| 46 | #include "xf86.h"
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| 47 | #include "xf86Modes.h"
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| 48 |
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| 49 | #include <string.h>
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| 50 | #else
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| 51 | # include "VBoxClient.h"
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| 52 | # include "display-svga-xf86cvt.h"
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| 53 | #endif
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| 54 |
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| 55 | /*
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| 56 | * This is a slightly modified version of the xf86CVTMode function from
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| 57 | * xf86cvt.c from the xorg xserver source code. Computes several parameters
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| 58 | * of a display mode out of horizontal and vertical resolutions. Replicated
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| 59 | * here to avoid further dependencies.
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| 60 | *
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| 61 | *----------------------------------------------------------------------------
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| 62 | *
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| 63 | * Generate a CVT standard mode from HDisplay, VDisplay and VRefresh.
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| 64 | *
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| 65 | * These calculations are stolen from the CVT calculation spreadsheet written
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| 66 | * by Graham Loveridge. He seems to be claiming no copyright and there seems to
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| 67 | * be no license attached to this. He apparently just wants to see his name
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| 68 | * mentioned.
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| 69 | *
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| 70 | * This file can be found at http://www.vesa.org/Public/CVT/CVTd6r1.xls
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| 71 | *
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| 72 | * Comments and structure corresponds to the comments and structure of the xls.
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| 73 | * This should ease importing of future changes to the standard (not very
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| 74 | * likely though).
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| 75 | *
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| 76 | * About margins; i'm sure that they are to be the bit between HDisplay and
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| 77 | * HBlankStart, HBlankEnd and HTotal, VDisplay and VBlankStart, VBlankEnd and
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| 78 | * VTotal, where the overscan colour is shown. FB seems to call _all_ blanking
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| 79 | * outside sync "margin" for some reason. Since we prefer seeing proper
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| 80 | * blanking instead of the overscan colour, and since the Crtc* values will
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| 81 | * probably get altered after us, we will disable margins altogether. With
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| 82 | * these calculations, Margins will plainly expand H/VDisplay, and we don't
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| 83 | * want that. -- libv
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| 84 | *
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| 85 | */
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| 86 | DisplayModeR VBoxClient_xf86CVTMode(int HDisplay, int VDisplay, float VRefresh /* Herz */, bool Reduced, bool Interlaced)
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| 87 | {
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| 88 | DisplayModeR Mode;
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| 89 |
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| 90 | /* 1) top/bottom margin size (% of height) - default: 1.8 */
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| 91 | #define CVT_MARGIN_PERCENTAGE 1.8
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| 92 |
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| 93 | /* 2) character cell horizontal granularity (pixels) - default 8 */
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| 94 | #define CVT_H_GRANULARITY 8
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| 95 |
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| 96 | /* 4) Minimum vertical porch (lines) - default 3 */
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| 97 | #define CVT_MIN_V_PORCH 3
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| 98 |
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| 99 | /* 4) Minimum number of vertical back porch lines - default 6 */
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| 100 | #define CVT_MIN_V_BPORCH 6
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| 101 |
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| 102 | /* Pixel Clock step (kHz) */
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| 103 | #define CVT_CLOCK_STEP 250
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| 104 |
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| 105 | bool Margins = false;
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| 106 | float VFieldRate, HPeriod;
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| 107 | int HDisplayRnd, HMargin;
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| 108 | int VDisplayRnd, VMargin, VSync;
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| 109 | float Interlace; /* Please rename this */
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| 110 |
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| 111 | /* CVT default is 60.0Hz */
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| 112 | if (!VRefresh)
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| 113 | VRefresh = 60.0;
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| 114 |
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| 115 | /* 1. Required field rate */
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| 116 | if (Interlaced)
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| 117 | VFieldRate = VRefresh * 2;
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| 118 | else
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| 119 | VFieldRate = VRefresh;
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| 120 |
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| 121 | /* 2. Horizontal pixels */
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| 122 | HDisplayRnd = HDisplay - (HDisplay % CVT_H_GRANULARITY);
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| 123 |
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| 124 | /* 3. Determine left and right borders */
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| 125 | if (Margins) {
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| 126 | /* right margin is actually exactly the same as left */
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| 127 | HMargin = (int)((float)HDisplayRnd * CVT_MARGIN_PERCENTAGE / 100.0);
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| 128 | HMargin -= HMargin % CVT_H_GRANULARITY;
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| 129 | }
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| 130 | else
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| 131 | HMargin = 0;
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| 132 |
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| 133 | /* 4. Find total active pixels */
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| 134 | Mode.HDisplay = HDisplayRnd + 2 * HMargin;
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| 135 |
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| 136 | /* 5. Find number of lines per field */
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| 137 | if (Interlaced)
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| 138 | VDisplayRnd = VDisplay / 2;
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| 139 | else
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| 140 | VDisplayRnd = VDisplay;
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| 141 |
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| 142 | /* 6. Find top and bottom margins */
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| 143 | /* nope. */
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| 144 | if (Margins)
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| 145 | /* top and bottom margins are equal again. */
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| 146 | VMargin = (int)((float)VDisplayRnd * CVT_MARGIN_PERCENTAGE / 100.0);
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| 147 | else
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| 148 | VMargin = 0;
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| 149 |
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| 150 | Mode.VDisplay = VDisplay + 2 * VMargin;
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| 151 |
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| 152 | /* 7. Interlace */
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| 153 | if (Interlaced)
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| 154 | Interlace = 0.5;
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| 155 | else
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| 156 | Interlace = 0.0;
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| 157 |
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| 158 | /* Determine VSync Width from aspect ratio */
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| 159 | if (!(VDisplay % 3) && ((VDisplay * 4 / 3) == HDisplay))
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| 160 | VSync = 4;
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| 161 | else if (!(VDisplay % 9) && ((VDisplay * 16 / 9) == HDisplay))
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| 162 | VSync = 5;
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| 163 | else if (!(VDisplay % 10) && ((VDisplay * 16 / 10) == HDisplay))
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| 164 | VSync = 6;
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| 165 | else if (!(VDisplay % 4) && ((VDisplay * 5 / 4) == HDisplay))
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| 166 | VSync = 7;
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| 167 | else if (!(VDisplay % 9) && ((VDisplay * 15 / 9) == HDisplay))
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| 168 | VSync = 7;
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| 169 | else /* Custom */
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| 170 | VSync = 10;
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| 171 |
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| 172 | if (!Reduced) { /* simplified GTF calculation */
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| 173 |
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| 174 | /* 4) Minimum time of vertical sync + back porch interval (µs)
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| 175 | * default 550.0 */
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| 176 | #define CVT_MIN_VSYNC_BP 550.0
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| 177 |
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| 178 | /* 3) Nominal HSync width (% of line period) - default 8 */
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| 179 | #define CVT_HSYNC_PERCENTAGE 8
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| 180 |
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| 181 | float HBlankPercentage;
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| 182 | int VSyncAndBackPorch, VBackPorch;
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| 183 | int HBlank;
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| 184 |
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| 185 | /* 8. Estimated Horizontal period */
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| 186 | HPeriod = ((float)(1000000.0 / VFieldRate - CVT_MIN_VSYNC_BP))
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| 187 | / (VDisplayRnd + 2 * VMargin + CVT_MIN_V_PORCH + Interlace);
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| 188 |
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| 189 | /* 9. Find number of lines in sync + backporch */
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| 190 | if ((int)(CVT_MIN_VSYNC_BP / HPeriod) + 1 < VSync + CVT_MIN_V_PORCH)
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| 191 | VSyncAndBackPorch = VSync + CVT_MIN_V_PORCH;
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| 192 | else
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| 193 | VSyncAndBackPorch = (int)(CVT_MIN_VSYNC_BP / HPeriod) + 1;
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| 194 |
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| 195 | /* 10. Find number of lines in back porch */
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| 196 | VBackPorch = VSyncAndBackPorch - VSync;
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| 197 | (void) VBackPorch;
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| 198 |
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| 199 | /* 11. Find total number of lines in vertical field */
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| 200 | Mode.VTotal = (int)(VDisplayRnd + 2 * VMargin + VSyncAndBackPorch + Interlace + CVT_MIN_V_PORCH);
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| 201 |
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| 202 | /* 5) Definition of Horizontal blanking time limitation */
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| 203 | /* Gradient (%/kHz) - default 600 */
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| 204 | #define CVT_M_FACTOR 600
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| 205 |
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| 206 | /* Offset (%) - default 40 */
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| 207 | #define CVT_C_FACTOR 40
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| 208 |
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| 209 | /* Blanking time scaling factor - default 128 */
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| 210 | #define CVT_K_FACTOR 128
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| 211 |
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| 212 | /* Scaling factor weighting - default 20 */
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| 213 | #define CVT_J_FACTOR 20
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| 214 |
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| 215 | #define CVT_M_PRIME (CVT_M_FACTOR * CVT_K_FACTOR / 256)
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| 216 | #define CVT_C_PRIME ((CVT_C_FACTOR - CVT_J_FACTOR) * CVT_K_FACTOR / 256 + CVT_J_FACTOR)
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| 217 |
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| 218 | /* 12. Find ideal blanking duty cycle from formula */
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| 219 | HBlankPercentage = CVT_C_PRIME - CVT_M_PRIME * HPeriod / 1000.0;
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| 220 |
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| 221 | /* 13. Blanking time */
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| 222 | if (HBlankPercentage < 20)
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| 223 | HBlankPercentage = 20;
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| 224 |
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| 225 | HBlank = (int)(Mode.HDisplay * HBlankPercentage / (100.0 - HBlankPercentage));
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| 226 | HBlank -= HBlank % (2 * CVT_H_GRANULARITY);
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| 227 |
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| 228 | /* 14. Find total number of pixels in a line. */
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| 229 | Mode.HTotal = Mode.HDisplay + HBlank;
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| 230 |
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| 231 | /* Fill in HSync values */
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| 232 | Mode.HSyncEnd = Mode.HDisplay + HBlank / 2;
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| 233 |
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| 234 | Mode.HSyncStart = Mode.HSyncEnd - (Mode.HTotal * CVT_HSYNC_PERCENTAGE) / 100;
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| 235 | Mode.HSyncStart += CVT_H_GRANULARITY - Mode.HSyncStart % CVT_H_GRANULARITY;
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| 236 |
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| 237 | /* Fill in VSync values */
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| 238 | Mode.VSyncStart = Mode.VDisplay + CVT_MIN_V_PORCH;
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| 239 | Mode.VSyncEnd = Mode.VSyncStart + VSync;
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| 240 |
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| 241 | }
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| 242 | else { /* Reduced blanking */
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| 243 | /* Minimum vertical blanking interval time (µs) - default 460 */
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| 244 | #define CVT_RB_MIN_VBLANK 460.0
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| 245 |
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| 246 | /* Fixed number of clocks for horizontal sync */
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| 247 | #define CVT_RB_H_SYNC 32.0
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| 248 |
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| 249 | /* Fixed number of clocks for horizontal blanking */
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| 250 | #define CVT_RB_H_BLANK 160.0
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| 251 |
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| 252 | /* Fixed number of lines for vertical front porch - default 3 */
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| 253 | #define CVT_RB_VFPORCH 3
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| 254 |
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| 255 | int VBILines;
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| 256 |
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| 257 | /* 8. Estimate Horizontal period. */
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| 258 | HPeriod = ((float)(1000000.0 / VFieldRate - CVT_RB_MIN_VBLANK)) / (VDisplayRnd + 2 * VMargin);
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| 259 |
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| 260 | /* 9. Find number of lines in vertical blanking */
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| 261 | VBILines = (int)((float)CVT_RB_MIN_VBLANK / HPeriod + 1);
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| 262 |
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| 263 | /* 10. Check if vertical blanking is sufficient */
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| 264 | if (VBILines < CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH)
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| 265 | VBILines = CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH;
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| 266 |
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| 267 | /* 11. Find total number of lines in vertical field */
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| 268 | Mode.VTotal = (int)(VDisplayRnd + 2 * VMargin + Interlace + VBILines);
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| 269 |
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| 270 | /* 12. Find total number of pixels in a line */
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| 271 | Mode.HTotal = (int)(Mode.HDisplay + CVT_RB_H_BLANK);
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| 272 |
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| 273 | /* Fill in HSync values */
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| 274 | Mode.HSyncEnd = (int)(Mode.HDisplay + CVT_RB_H_BLANK / 2);
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| 275 | Mode.HSyncStart = (int)(Mode.HSyncEnd - CVT_RB_H_SYNC);
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| 276 |
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| 277 | /* Fill in VSync values */
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| 278 | Mode.VSyncStart = Mode.VDisplay + CVT_RB_VFPORCH;
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| 279 | Mode.VSyncEnd = Mode.VSyncStart + VSync;
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| 280 | }
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| 281 | /* 15/13. Find pixel clock frequency (kHz for xf86) */
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| 282 | Mode.Clock = (int)(Mode.HTotal * 1000.0 / HPeriod);
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| 283 | Mode.Clock -= Mode.Clock % CVT_CLOCK_STEP;
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| 284 |
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| 285 | /* 16/14. Find actual Horizontal Frequency (kHz) */
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| 286 | Mode.HSync = (float)Mode.Clock / (float)Mode.HTotal;
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| 287 |
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| 288 | /* 17/15. Find actual Field rate */
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| 289 | Mode.VRefresh = (1000.0 * (float)Mode.Clock) / (float)(Mode.HTotal * Mode.VTotal);
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| 290 |
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| 291 | /* 18/16. Find actual vertical frame frequency */
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| 292 | /* ignore - just set the mode flag for interlaced */
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| 293 | if (Interlaced)
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| 294 | Mode.VTotal *= 2;
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| 295 |
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| 296 | #if 0
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| 297 | XNFasprintf(&tmp, "%dx%d", HDisplay, VDisplay);
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| 298 | Mode->name = tmp;
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| 299 |
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| 300 | if (Reduced)
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| 301 | Mode->Flags |= V_PHSYNC | V_NVSYNC;
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| 302 | else
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| 303 | Mode->Flags |= V_NHSYNC | V_PVSYNC;
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| 304 |
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| 305 | if (Interlaced)
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| 306 | Mode->Flags |= V_INTERLACE;
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| 307 | #endif
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| 308 |
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| 309 | return Mode;
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| 310 | }
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