/* * Copyright 2005-2006 Luc Verhaegen. * * 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 * the rights to use, copy, modify, merge, publish, distribute, sublicense, * 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 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 NONINFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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. */ /* * The reason for having this function in a file of its own is * so that ../utils/cvt/cvt can link to it, and that xf86CVTMode * code is shared directly. */ #include "xf86.h" /* * Generate a CVT standard mode from HDisplay, VDisplay and VRefresh. * * These calculations are stolen from the CVT calculation spreadsheet written * by Graham Loveridge. He seems to be claiming no copyright and there seems to * be no license attached to this. He apparently just wants to see his name * mentioned. * * This file can be found at http://www.vesa.org/Public/CVT/CVTd6r1.xls * * Comments and structure corresponds to the comments and structure of the xls. * This should ease importing of future changes to the standard (not very * likely though). * * About margins; i'm sure that they are to be the bit between HDisplay and * HBlankStart, HBlankEnd and HTotal, VDisplay and VBlankStart, VBlankEnd and * VTotal, where the overscan colour is shown. FB seems to call _all_ blanking * outside sync "margin" for some reason. Since we prefer seeing proper * blanking instead of the overscan colour, and since the Crtc* values will * probably get altered after us, we will disable margins altogether. With * these calculations, Margins will plainly expand H/VDisplay, and we don't * want that. -- libv * */ _X_EXPORT DisplayModePtr xf86CVTMode(int HDisplay, int VDisplay, float VRefresh, Bool Reduced, Bool Interlaced) { DisplayModeRec *Mode = xnfalloc(sizeof(DisplayModeRec)); /* 1) top/bottom margin size (% of height) - default: 1.8 */ #define CVT_MARGIN_PERCENTAGE 1.8 /* 2) character cell horizontal granularity (pixels) - default 8 */ #define CVT_H_GRANULARITY 8 /* 4) Minimum vertical porch (lines) - default 3 */ #define CVT_MIN_V_PORCH 3 /* 4) Minimum number of vertical back porch lines - default 6 */ #define CVT_MIN_V_BPORCH 6 /* Pixel Clock step (kHz) */ #define CVT_CLOCK_STEP 250 Bool Margins = FALSE; float VFieldRate, HPeriod; int HDisplayRnd, HMargin; int VDisplayRnd, VMargin, VSync; float Interlace; /* Please rename this */ memset(Mode, 0, sizeof(DisplayModeRec)); /* CVT default is 60.0Hz */ if (!VRefresh) VRefresh = 60.0; /* 1. Required field rate */ if (Interlaced) VFieldRate = VRefresh * 2; else VFieldRate = VRefresh; /* 2. Horizontal pixels */ HDisplayRnd = HDisplay - (HDisplay % CVT_H_GRANULARITY); /* 3. Determine left and right borders */ if (Margins) { /* right margin is actually exactly the same as left */ HMargin = (((float) HDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0); HMargin -= HMargin % CVT_H_GRANULARITY; } else HMargin = 0; /* 4. Find total active pixels */ Mode->HDisplay = HDisplayRnd + 2*HMargin; /* 5. Find number of lines per field */ if (Interlaced) VDisplayRnd = VDisplay / 2; else VDisplayRnd = VDisplay; /* 6. Find top and bottom margins */ /* nope. */ if (Margins) /* top and bottom margins are equal again. */ VMargin = (((float) VDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0); else VMargin = 0; Mode->VDisplay = VDisplay + 2*VMargin; /* 7. Interlace */ if (Interlaced) Interlace = 0.5; else Interlace = 0.0; /* Determine VSync Width from aspect ratio */ if (!(VDisplay % 3) && ((VDisplay * 4 / 3) == HDisplay)) VSync = 4; else if (!(VDisplay % 9) && ((VDisplay * 16 / 9) == HDisplay)) VSync = 5; else if (!(VDisplay % 10) && ((VDisplay * 16 / 10) == HDisplay)) VSync = 6; else if (!(VDisplay % 4) && ((VDisplay * 5 / 4) == HDisplay)) VSync = 7; else if (!(VDisplay % 9) && ((VDisplay * 15 / 9) == HDisplay)) VSync = 7; else /* Custom */ VSync = 10; if (!Reduced) { /* simplified GTF calculation */ /* 4) Minimum time of vertical sync + back porch interval (µs) * default 550.0 */ #define CVT_MIN_VSYNC_BP 550.0 /* 3) Nominal HSync width (% of line period) - default 8 */ #define CVT_HSYNC_PERCENTAGE 8 float HBlankPercentage; int VSyncAndBackPorch, VBackPorch; int HBlank; /* 8. Estimated Horizontal period */ HPeriod = ((float) (1000000.0 / VFieldRate - CVT_MIN_VSYNC_BP)) / (VDisplayRnd + 2 * VMargin + CVT_MIN_V_PORCH + Interlace); /* 9. Find number of lines in sync + backporch */ if (((int)(CVT_MIN_VSYNC_BP / HPeriod) + 1) < (VSync + CVT_MIN_V_PORCH)) VSyncAndBackPorch = VSync + CVT_MIN_V_PORCH; else VSyncAndBackPorch = (int)(CVT_MIN_VSYNC_BP / HPeriod) + 1; /* 10. Find number of lines in back porch */ VBackPorch = VSyncAndBackPorch - VSync; /* 11. Find total number of lines in vertical field */ Mode->VTotal = VDisplayRnd + 2 * VMargin + VSyncAndBackPorch + Interlace + CVT_MIN_V_PORCH; /* 5) Definition of Horizontal blanking time limitation */ /* Gradient (%/kHz) - default 600 */ #define CVT_M_FACTOR 600 /* Offset (%) - default 40 */ #define CVT_C_FACTOR 40 /* Blanking time scaling factor - default 128 */ #define CVT_K_FACTOR 128 /* Scaling factor weighting - default 20 */ #define CVT_J_FACTOR 20 #define CVT_M_PRIME CVT_M_FACTOR * CVT_K_FACTOR / 256 #define CVT_C_PRIME (CVT_C_FACTOR - CVT_J_FACTOR) * CVT_K_FACTOR / 256 + \ CVT_J_FACTOR /* 12. Find ideal blanking duty cycle from formula */ HBlankPercentage = CVT_C_PRIME - CVT_M_PRIME * HPeriod/1000.0; /* 13. Blanking time */ if (HBlankPercentage < 20) HBlankPercentage = 20; HBlank = Mode->HDisplay * HBlankPercentage/(100.0 - HBlankPercentage); HBlank -= HBlank % (2*CVT_H_GRANULARITY); /* 14. Find total number of pixels in a line. */ Mode->HTotal = Mode->HDisplay + HBlank; /* Fill in HSync values */ Mode->HSyncEnd = Mode->HDisplay + HBlank / 2; Mode->HSyncStart = Mode->HSyncEnd - (Mode->HTotal * CVT_HSYNC_PERCENTAGE) / 100; Mode->HSyncStart += CVT_H_GRANULARITY - Mode->HSyncStart % CVT_H_GRANULARITY; /* Fill in VSync values */ Mode->VSyncStart = Mode->VDisplay + CVT_MIN_V_PORCH; Mode->VSyncEnd = Mode->VSyncStart + VSync; } else { /* Reduced blanking */ /* Minimum vertical blanking interval time (µs) - default 460 */ #define CVT_RB_MIN_VBLANK 460.0 /* Fixed number of clocks for horizontal sync */ #define CVT_RB_H_SYNC 32.0 /* Fixed number of clocks for horizontal blanking */ #define CVT_RB_H_BLANK 160.0 /* Fixed number of lines for vertical front porch - default 3 */ #define CVT_RB_VFPORCH 3 int VBILines; /* 8. Estimate Horizontal period. */ HPeriod = ((float) (1000000.0 / VFieldRate - CVT_RB_MIN_VBLANK)) / (VDisplayRnd + 2*VMargin); /* 9. Find number of lines in vertical blanking */ VBILines = ((float) CVT_RB_MIN_VBLANK) / HPeriod + 1; /* 10. Check if vertical blanking is sufficient */ if (VBILines < (CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH)) VBILines = CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH; /* 11. Find total number of lines in vertical field */ Mode->VTotal = VDisplayRnd + 2 * VMargin + Interlace + VBILines; /* 12. Find total number of pixels in a line */ Mode->HTotal = Mode->HDisplay + CVT_RB_H_BLANK; /* Fill in HSync values */ Mode->HSyncEnd = Mode->HDisplay + CVT_RB_H_BLANK / 2; Mode->HSyncStart = Mode->HSyncEnd - CVT_RB_H_SYNC; /* Fill in VSync values */ Mode->VSyncStart = Mode->VDisplay + CVT_RB_VFPORCH; Mode->VSyncEnd = Mode->VSyncStart + VSync; } /* 15/13. Find pixel clock frequency (kHz for xf86) */ Mode->Clock = Mode->HTotal * 1000.0 / HPeriod; Mode->Clock -= Mode->Clock % CVT_CLOCK_STEP; /* 16/14. Find actual Horizontal Frequency (kHz) */ Mode->HSync = ((float) Mode->Clock) / ((float) Mode->HTotal); /* 17/15. Find actual Field rate */ Mode->VRefresh = (1000.0 * ((float) Mode->Clock)) / ((float) (Mode->HTotal * Mode->VTotal)); /* 18/16. Find actual vertical frame frequency */ /* ignore - just set the mode flag for interlaced */ if (Interlaced) Mode->VTotal *= 2; { char Name[256]; Name[0] = 0; snprintf(Name, 256, "%dx%d", HDisplay, VDisplay); Mode->name = xnfalloc(strlen(Name) + 1); memcpy(Mode->name, Name, strlen(Name) + 1); } if (Reduced) Mode->Flags |= V_PHSYNC | V_NVSYNC; else Mode->Flags |= V_NHSYNC | V_PVSYNC; if (Interlaced) Mode->Flags |= V_INTERLACE; return Mode; }