/* * 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. */ #include "minitru-int.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 * */ struct mt_mode * mt_cvt_mode(uint32_t hdisplay, uint32_t vdisplay, float refresh, uint32_t flags) { struct mt_mode *mode = mt_mode_alloc(); int interlaced = !!(flags & MT_FLAG_INTERLACED); int reduced = !!(flags & MT_FLAG_REDUCED); /* 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 uint32_t margins = 0; float vfieldrate, hperiod; int hdisplayrnd, hmargin; int vdisplayrnd, vmargin, vsync; float interlace; /* please rename this */ /* CVT default is 60.0Hz */ if (!refresh) refresh = 60.0; /* 1. Required field rate */ if (interlaced) vfieldrate = refresh * 2; else vfieldrate = refresh; /* 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; /* 18/16. Find actual vertical frame frequency */ /* ignore - just set the mode flag for interlaced */ if (interlaced) mode->vtotal *= 2; if (reduced) mode->flags |= MT_FLAG_PHSYNC | MT_FLAG_NVSYNC; else mode->flags |= MT_FLAG_NHSYNC | MT_FLAG_PVSYNC; if (interlaced) mode->flags |= MT_FLAG_INTERLACED; return mode; }