302 lines
9.9 KiB
C
302 lines
9.9 KiB
C
/*
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* Copyright 2005-2006 Luc Verhaegen.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* The reason for having this function in a file of its own is
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* so that ../utils/cvt/cvt can link to it, and that xf86CVTMode
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* code is shared directly.
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*/
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#ifdef HAVE_XORG_CONFIG_H
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#include <xorg-config.h>
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#else
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#endif
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#include "xf86.h"
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#include "xf86Modes.h"
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#include <string.h>
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/*
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* Generate a CVT standard mode from HDisplay, VDisplay and VRefresh.
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*
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* These calculations are stolen from the CVT calculation spreadsheet written
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* by Graham Loveridge. He seems to be claiming no copyright and there seems to
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* be no license attached to this. He apparently just wants to see his name
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* mentioned.
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*
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* This file can be found at http://www.vesa.org/Public/CVT/CVTd6r1.xls
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*
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* Comments and structure corresponds to the comments and structure of the xls.
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* This should ease importing of future changes to the standard (not very
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* likely though).
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*
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* About margins; i'm sure that they are to be the bit between HDisplay and
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* HBlankStart, HBlankEnd and HTotal, VDisplay and VBlankStart, VBlankEnd and
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* VTotal, where the overscan colour is shown. FB seems to call _all_ blanking
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* outside sync "margin" for some reason. Since we prefer seeing proper
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* blanking instead of the overscan colour, and since the Crtc* values will
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* probably get altered after us, we will disable margins altogether. With
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* these calculations, Margins will plainly expand H/VDisplay, and we don't
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* want that. -- libv
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*
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*/
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DisplayModePtr
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xf86CVTMode(int HDisplay, int VDisplay, float VRefresh, Bool Reduced,
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Bool Interlaced)
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{
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DisplayModeRec *Mode = xnfcalloc(1, sizeof(DisplayModeRec));
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/* 1) top/bottom margin size (% of height) - default: 1.8 */
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#define CVT_MARGIN_PERCENTAGE 1.8
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/* 2) character cell horizontal granularity (pixels) - default 8 */
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#define CVT_H_GRANULARITY 8
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/* 4) Minimum vertical porch (lines) - default 3 */
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#define CVT_MIN_V_PORCH 3
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/* 4) Minimum number of vertical back porch lines - default 6 */
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#define CVT_MIN_V_BPORCH 6
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/* Pixel Clock step (kHz) */
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#define CVT_CLOCK_STEP 250
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Bool Margins = FALSE;
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float VFieldRate, HPeriod;
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int HDisplayRnd, HMargin;
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int VDisplayRnd, VMargin, VSync;
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float Interlace; /* Please rename this */
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/* CVT default is 60.0Hz */
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if (!VRefresh)
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VRefresh = 60.0;
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/* 1. Required field rate */
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if (Interlaced)
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VFieldRate = VRefresh * 2;
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else
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VFieldRate = VRefresh;
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/* 2. Horizontal pixels */
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HDisplayRnd = HDisplay - (HDisplay % CVT_H_GRANULARITY);
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/* 3. Determine left and right borders */
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if (Margins) {
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/* right margin is actually exactly the same as left */
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HMargin = (((float) HDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0);
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HMargin -= HMargin % CVT_H_GRANULARITY;
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} else
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HMargin = 0;
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/* 4. Find total active pixels */
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Mode->HDisplay = HDisplayRnd + 2*HMargin;
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/* 5. Find number of lines per field */
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if (Interlaced)
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VDisplayRnd = VDisplay / 2;
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else
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VDisplayRnd = VDisplay;
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/* 6. Find top and bottom margins */
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/* nope. */
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if (Margins)
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/* top and bottom margins are equal again. */
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VMargin = (((float) VDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0);
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else
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VMargin = 0;
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Mode->VDisplay = VDisplay + 2*VMargin;
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/* 7. Interlace */
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if (Interlaced)
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Interlace = 0.5;
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else
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Interlace = 0.0;
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/* Determine VSync Width from aspect ratio */
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if (!(VDisplay % 3) && ((VDisplay * 4 / 3) == HDisplay))
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VSync = 4;
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else if (!(VDisplay % 9) && ((VDisplay * 16 / 9) == HDisplay))
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VSync = 5;
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else if (!(VDisplay % 10) && ((VDisplay * 16 / 10) == HDisplay))
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VSync = 6;
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else if (!(VDisplay % 4) && ((VDisplay * 5 / 4) == HDisplay))
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VSync = 7;
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else if (!(VDisplay % 9) && ((VDisplay * 15 / 9) == HDisplay))
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VSync = 7;
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else /* Custom */
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VSync = 10;
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if (!Reduced) { /* simplified GTF calculation */
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/* 4) Minimum time of vertical sync + back porch interval (<28>s)
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* default 550.0 */
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#define CVT_MIN_VSYNC_BP 550.0
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/* 3) Nominal HSync width (% of line period) - default 8 */
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#define CVT_HSYNC_PERCENTAGE 8
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float HBlankPercentage;
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int VSyncAndBackPorch, VBackPorch;
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int HBlank;
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/* 8. Estimated Horizontal period */
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HPeriod = ((float) (1000000.0 / VFieldRate - CVT_MIN_VSYNC_BP)) /
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(VDisplayRnd + 2 * VMargin + CVT_MIN_V_PORCH + Interlace);
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/* 9. Find number of lines in sync + backporch */
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if (((int)(CVT_MIN_VSYNC_BP / HPeriod) + 1) < (VSync + CVT_MIN_V_PORCH))
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VSyncAndBackPorch = VSync + CVT_MIN_V_PORCH;
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else
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VSyncAndBackPorch = (int)(CVT_MIN_VSYNC_BP / HPeriod) + 1;
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/* 10. Find number of lines in back porch */
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VBackPorch = VSyncAndBackPorch - VSync;
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/* 11. Find total number of lines in vertical field */
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Mode->VTotal = VDisplayRnd + 2 * VMargin + VSyncAndBackPorch + Interlace
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+ CVT_MIN_V_PORCH;
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/* 5) Definition of Horizontal blanking time limitation */
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/* Gradient (%/kHz) - default 600 */
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#define CVT_M_FACTOR 600
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/* Offset (%) - default 40 */
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#define CVT_C_FACTOR 40
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/* Blanking time scaling factor - default 128 */
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#define CVT_K_FACTOR 128
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/* Scaling factor weighting - default 20 */
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#define CVT_J_FACTOR 20
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#define CVT_M_PRIME CVT_M_FACTOR * CVT_K_FACTOR / 256
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#define CVT_C_PRIME (CVT_C_FACTOR - CVT_J_FACTOR) * CVT_K_FACTOR / 256 + \
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CVT_J_FACTOR
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/* 12. Find ideal blanking duty cycle from formula */
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HBlankPercentage = CVT_C_PRIME - CVT_M_PRIME * HPeriod/1000.0;
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/* 13. Blanking time */
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if (HBlankPercentage < 20)
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HBlankPercentage = 20;
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HBlank = Mode->HDisplay * HBlankPercentage/(100.0 - HBlankPercentage);
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HBlank -= HBlank % (2*CVT_H_GRANULARITY);
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/* 14. Find total number of pixels in a line. */
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Mode->HTotal = Mode->HDisplay + HBlank;
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/* Fill in HSync values */
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Mode->HSyncEnd = Mode->HDisplay + HBlank / 2;
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Mode->HSyncStart = Mode->HSyncEnd -
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(Mode->HTotal * CVT_HSYNC_PERCENTAGE) / 100;
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Mode->HSyncStart += CVT_H_GRANULARITY -
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Mode->HSyncStart % CVT_H_GRANULARITY;
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/* Fill in VSync values */
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Mode->VSyncStart = Mode->VDisplay + CVT_MIN_V_PORCH;
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Mode->VSyncEnd = Mode->VSyncStart + VSync;
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} else { /* Reduced blanking */
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/* Minimum vertical blanking interval time (<28>s) - default 460 */
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#define CVT_RB_MIN_VBLANK 460.0
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/* Fixed number of clocks for horizontal sync */
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#define CVT_RB_H_SYNC 32.0
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/* Fixed number of clocks for horizontal blanking */
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#define CVT_RB_H_BLANK 160.0
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/* Fixed number of lines for vertical front porch - default 3 */
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#define CVT_RB_VFPORCH 3
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int VBILines;
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/* 8. Estimate Horizontal period. */
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HPeriod = ((float) (1000000.0 / VFieldRate - CVT_RB_MIN_VBLANK)) /
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(VDisplayRnd + 2*VMargin);
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/* 9. Find number of lines in vertical blanking */
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VBILines = ((float) CVT_RB_MIN_VBLANK) / HPeriod + 1;
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/* 10. Check if vertical blanking is sufficient */
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if (VBILines < (CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH))
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VBILines = CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH;
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/* 11. Find total number of lines in vertical field */
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Mode->VTotal = VDisplayRnd + 2 * VMargin + Interlace + VBILines;
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/* 12. Find total number of pixels in a line */
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Mode->HTotal = Mode->HDisplay + CVT_RB_H_BLANK;
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/* Fill in HSync values */
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Mode->HSyncEnd = Mode->HDisplay + CVT_RB_H_BLANK / 2;
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Mode->HSyncStart = Mode->HSyncEnd - CVT_RB_H_SYNC;
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/* Fill in VSync values */
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Mode->VSyncStart = Mode->VDisplay + CVT_RB_VFPORCH;
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Mode->VSyncEnd = Mode->VSyncStart + VSync;
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}
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/* 15/13. Find pixel clock frequency (kHz for xf86) */
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Mode->Clock = Mode->HTotal * 1000.0 / HPeriod;
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Mode->Clock -= Mode->Clock % CVT_CLOCK_STEP;
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/* 16/14. Find actual Horizontal Frequency (kHz) */
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Mode->HSync = ((float) Mode->Clock) / ((float) Mode->HTotal);
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/* 17/15. Find actual Field rate */
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Mode->VRefresh = (1000.0 * ((float) Mode->Clock)) /
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((float) (Mode->HTotal * Mode->VTotal));
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/* 18/16. Find actual vertical frame frequency */
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/* ignore - just set the mode flag for interlaced */
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if (Interlaced)
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Mode->VTotal *= 2;
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{
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char Name[256];
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Name[0] = 0;
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snprintf(Name, 256, "%dx%d", HDisplay, VDisplay);
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Mode->name = xnfalloc(strlen(Name) + 1);
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memcpy(Mode->name, Name, strlen(Name) + 1);
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}
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if (Reduced)
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Mode->Flags |= V_PHSYNC | V_NVSYNC;
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else
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Mode->Flags |= V_NHSYNC | V_PVSYNC;
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if (Interlaced)
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Mode->Flags |= V_INTERLACE;
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return Mode;
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}
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