/* gtf.c Generate mode timings using the GTF Timing Standard * * gcc gtf.c -o gtf -lm -Wall * * Copyright (c) 2001, Andy Ritger aritger@nvidia.com * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * o Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * o Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * o Neither the name of NVIDIA nor the names of its contributors * may be used to endorse or promote products derived from this * software without specific prior written permission. * * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL * THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * * * This program is based on the Generalized Timing Formula(GTF TM) * Standard Version: 1.0, Revision: 1.0 * * The GTF Document contains the following Copyright information: * * Copyright (c) 1994, 1995, 1996 - Video Electronics Standards * Association. Duplication of this document within VESA member * companies for review purposes is permitted. All other rights * reserved. * * While every precaution has been taken in the preparation * of this standard, the Video Electronics Standards Association and * its contributors assume no responsibility for errors or omissions, * and make no warranties, expressed or implied, of functionality * of suitability for any purpose. The sample code contained within * this standard may be used without restriction. * * * * The GTF EXCEL(TM) SPREADSHEET, a sample (and the definitive) * implementation of the GTF Timing Standard, is available at: * * ftp://ftp.vesa.org/pub/GTF/GTF_V1R1.xls * * * * This program takes a desired resolution and vertical refresh rate, * and computes mode timings according to the GTF Timing Standard. * These mode timings can then be formatted as an XServer modeline * or a mode description for use by fbset(8). * * * * NOTES: * * The GTF allows for computation of "margins" (the visible border * surrounding the addressable video); on most non-overscan type * systems, the margin period is zero. I've implemented the margin * computations but not enabled it because 1) I don't really have * any experience with this, and 2) neither XServer modelines nor * fbset fb.modes provide an obvious way for margin timings to be * included in their mode descriptions (needs more investigation). * * The GTF provides for computation of interlaced mode timings; * I've implemented the computations but not enabled them, yet. * I should probably enable and test this at some point. * * * * TODO: * * o Add support for interlaced modes. * * o Implement the other portions of the GTF: compute mode timings * given either the desired pixel clock or the desired horizontal * frequency. * * o It would be nice if this were more general purpose to do things * outside the scope of the GTF: like generate double scan mode * timings, for example. * * o Printing digits to the right of the decimal point when the * digits are 0 annoys me. * * o Error checking. * */ #ifdef HAVE_XORG_CONFIG_H # include <xorg-config.h> #endif #include <stdio.h> #include <stdlib.h> #include <string.h> #include <math.h> #define MARGIN_PERCENT 1.8 /* % of active vertical image */ #define CELL_GRAN 8.0 /* assumed character cell granularity */ #define MIN_PORCH 1 /* minimum front porch */ #define V_SYNC_RQD 3 /* width of vsync in lines */ #define H_SYNC_PERCENT 8.0 /* width of hsync as % of total line */ #define MIN_VSYNC_PLUS_BP 550.0 /* min time of vsync + back porch (microsec) */ #define M 600.0 /* blanking formula gradient */ #define C 40.0 /* blanking formula offset */ #define K 128.0 /* blanking formula scaling factor */ #define J 20.0 /* blanking formula scaling factor */ /* C' and M' are part of the Blanking Duty Cycle computation */ #define C_PRIME (((C - J) * K/256.0) + J) #define M_PRIME (K/256.0 * M) /* struct definitions */ typedef struct __mode { int hr, hss, hse, hfl; int vr, vss, vse, vfl; float pclk, h_freq, v_freq; } mode; typedef struct __options { int x, y; int xorgmode, fbmode; float v_freq; } options; /* prototypes */ void print_value(int n, char *name, float val); void print_xf86_mode (mode *m); void print_fb_mode (mode *m); mode *vert_refresh (int h_pixels, int v_lines, float freq, int interlaced, int margins); options *parse_command_line (int argc, char *argv[]); /* * print_value() - print the result of the named computation; this is * useful when comparing against the GTF EXCEL spreadsheet. */ int global_verbose = 0; void print_value(int n, char *name, float val) { if (global_verbose) { printf("%2d: %-27s: %15f\n", n, name, val); } } /* print_xf86_mode() - print the XServer modeline, given mode timings. */ void print_xf86_mode (mode *m) { printf ("\n"); printf (" # %dx%d @ %.2f Hz (GTF) hsync: %.2f kHz; pclk: %.2f MHz\n", m->hr, m->vr, m->v_freq, m->h_freq, m->pclk); printf (" Modeline \"%dx%d_%.2f\" %.2f" " %d %d %d %d" " %d %d %d %d" " -HSync +Vsync\n\n", m->hr, m->vr, m->v_freq, m->pclk, m->hr, m->hss, m->hse, m->hfl, m->vr, m->vss, m->vse, m->vfl); } /* * print_fb_mode() - print a mode description in fbset(8) format; * see the fb.modes(8) manpage. The timing description used in * this is rather odd; they use "left and right margin" to refer * to the portion of the hblank before and after the sync pulse * by conceptually wrapping the portion of the blank after the pulse * to infront of the visible region; ie: * * * Timing description I'm accustomed to: * * * * <--------1--------> <--2--> <--3--> <--4--> * _________ * |-------------------|_______| |_______ * * R SS SE FL * * 1: visible image * 2: blank before sync (aka front porch) * 3: sync pulse * 4: blank after sync (aka back porch) * R: Resolution * SS: Sync Start * SE: Sync End * FL: Frame Length * * * But the fb.modes format is: * * * <--4--> <--------1--------> <--2--> <--3--> * _________ * _______|-------------------|_______| | * * The fb.modes(8) manpage refers to <4> and <2> as the left and * right "margin" (as well as upper and lower margin in the vertical * direction) -- note that this has nothing to do with the term * "margin" used in the GTF Timing Standard. * * XXX always prints the 32 bit mode -- should I provide a command * line option to specify the bpp? It's simple enough for a user * to edit the mode description after it's generated. */ void print_fb_mode (mode *m) { printf ("\n"); printf ("mode \"%dx%d %.2fHz 32bit (GTF)\"\n", m->hr, m->vr, m->v_freq); printf (" # PCLK: %.2f MHz, H: %.2f kHz, V: %.2f Hz\n", m->pclk, m->h_freq, m->v_freq); printf (" geometry %d %d %d %d 32\n", m->hr, m->vr, m->hr, m->vr); printf (" timings %d %d %d %d %d %d %d\n", (int) rint(1000000.0/m->pclk),/* pixclock in picoseconds */ m->hfl - m->hse, /* left margin (in pixels) */ m->hss - m->hr, /* right margin (in pixels) */ m->vfl - m->vse, /* upper margin (in pixel lines) */ m->vss - m->vr, /* lower margin (in pixel lines) */ m->hse - m->hss, /* horizontal sync length (pixels) */ m->vse - m->vss); /* vert sync length (pixel lines) */ printf (" hsync low\n"); printf (" vsync high\n"); printf ("endmode\n\n"); } /* * vert_refresh() - as defined by the GTF Timing Standard, compute the * Stage 1 Parameters using the vertical refresh frequency. In other * words: input a desired resolution and desired refresh rate, and * output the GTF mode timings. * * XXX All the code is in place to compute interlaced modes, but I don't * feel like testing it right now. * * XXX margin computations are implemented but not tested (nor used by * XServer of fbset mode descriptions, from what I can tell). */ mode *vert_refresh (int h_pixels, int v_lines, float freq, int interlaced, int margins) { float h_pixels_rnd; float v_lines_rnd; float v_field_rate_rqd; float top_margin; float bottom_margin; float interlace; float h_period_est; float vsync_plus_bp; float v_back_porch; float total_v_lines; float v_field_rate_est; float h_period; float v_field_rate; float v_frame_rate; float left_margin; float right_margin; float total_active_pixels; float ideal_duty_cycle; float h_blank; float total_pixels; float pixel_freq; float h_freq; float h_sync; float h_front_porch; float v_odd_front_porch_lines; mode *m = (mode*) malloc (sizeof (mode)); /* 1. In order to give correct results, the number of horizontal * pixels requested is first processed to ensure that it is divisible * by the character size, by rounding it to the nearest character * cell boundary: * * [H PIXELS RND] = ((ROUND([H PIXELS]/[CELL GRAN RND],0))*[CELLGRAN RND]) */ h_pixels_rnd = rint((float) h_pixels / CELL_GRAN) * CELL_GRAN; print_value(1, "[H PIXELS RND]", h_pixels_rnd); /* 2. If interlace is requested, the number of vertical lines assumed * by the calculation must be halved, as the computation calculates * the number of vertical lines per field. In either case, the * number of lines is rounded to the nearest integer. * * [V LINES RND] = IF([INT RQD?]="y", ROUND([V LINES]/2,0), * ROUND([V LINES],0)) */ v_lines_rnd = interlaced ? rint((float) v_lines) / 2.0 : rint((float) v_lines); print_value(2, "[V LINES RND]", v_lines_rnd); /* 3. Find the frame rate required: * * [V FIELD RATE RQD] = IF([INT RQD?]="y", [I/P FREQ RQD]*2, * [I/P FREQ RQD]) */ v_field_rate_rqd = interlaced ? (freq * 2.0) : (freq); print_value(3, "[V FIELD RATE RQD]", v_field_rate_rqd); /* 4. Find number of lines in Top margin: * * [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y", * ROUND(([MARGIN%]/100*[V LINES RND]),0), * 0) */ top_margin = margins ? rint(MARGIN_PERCENT / 100.0 * v_lines_rnd) : (0.0); print_value(4, "[TOP MARGIN (LINES)]", top_margin); /* 5. Find number of lines in Bottom margin: * * [BOT MARGIN (LINES)] = IF([MARGINS RQD?]="Y", * ROUND(([MARGIN%]/100*[V LINES RND]),0), * 0) */ bottom_margin = margins ? rint(MARGIN_PERCENT/100.0 * v_lines_rnd) : (0.0); print_value(5, "[BOT MARGIN (LINES)]", bottom_margin); /* 6. If interlace is required, then set variable [INTERLACE]=0.5: * * [INTERLACE]=(IF([INT RQD?]="y",0.5,0)) */ interlace = interlaced ? 0.5 : 0.0; print_value(6, "[INTERLACE]", interlace); /* 7. Estimate the Horizontal period * * [H PERIOD EST] = ((1/[V FIELD RATE RQD]) - [MIN VSYNC+BP]/1000000) / * ([V LINES RND] + (2*[TOP MARGIN (LINES)]) + * [MIN PORCH RND]+[INTERLACE]) * 1000000 */ h_period_est = (((1.0/v_field_rate_rqd) - (MIN_VSYNC_PLUS_BP/1000000.0)) / (v_lines_rnd + (2*top_margin) + MIN_PORCH + interlace) * 1000000.0); print_value(7, "[H PERIOD EST]", h_period_est); /* 8. Find the number of lines in V sync + back porch: * * [V SYNC+BP] = ROUND(([MIN VSYNC+BP]/[H PERIOD EST]),0) */ vsync_plus_bp = rint(MIN_VSYNC_PLUS_BP/h_period_est); print_value(8, "[V SYNC+BP]", vsync_plus_bp); /* 9. Find the number of lines in V back porch alone: * * [V BACK PORCH] = [V SYNC+BP] - [V SYNC RND] * * XXX is "[V SYNC RND]" a typo? should be [V SYNC RQD]? */ v_back_porch = vsync_plus_bp - V_SYNC_RQD; print_value(9, "[V BACK PORCH]", v_back_porch); /* 10. Find the total number of lines in Vertical field period: * * [TOTAL V LINES] = [V LINES RND] + [TOP MARGIN (LINES)] + * [BOT MARGIN (LINES)] + [V SYNC+BP] + [INTERLACE] + * [MIN PORCH RND] */ total_v_lines = v_lines_rnd + top_margin + bottom_margin + vsync_plus_bp + interlace + MIN_PORCH; print_value(10, "[TOTAL V LINES]", total_v_lines); /* 11. Estimate the Vertical field frequency: * * [V FIELD RATE EST] = 1 / [H PERIOD EST] / [TOTAL V LINES] * 1000000 */ v_field_rate_est = 1.0 / h_period_est / total_v_lines * 1000000.0; print_value(11, "[V FIELD RATE EST]", v_field_rate_est); /* 12. Find the actual horizontal period: * * [H PERIOD] = [H PERIOD EST] / ([V FIELD RATE RQD] / [V FIELD RATE EST]) */ h_period = h_period_est / (v_field_rate_rqd / v_field_rate_est); print_value(12, "[H PERIOD]", h_period); /* 13. Find the actual Vertical field frequency: * * [V FIELD RATE] = 1 / [H PERIOD] / [TOTAL V LINES] * 1000000 */ v_field_rate = 1.0 / h_period / total_v_lines * 1000000.0; print_value(13, "[V FIELD RATE]", v_field_rate); /* 14. Find the Vertical frame frequency: * * [V FRAME RATE] = (IF([INT RQD?]="y", [V FIELD RATE]/2, [V FIELD RATE])) */ v_frame_rate = interlaced ? v_field_rate / 2.0 : v_field_rate; print_value(14, "[V FRAME RATE]", v_frame_rate); /* 15. Find number of pixels in left margin: * * [LEFT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y", * (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 / * [CELL GRAN RND]),0)) * [CELL GRAN RND], * 0)) */ left_margin = margins ? rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN : 0.0; print_value(15, "[LEFT MARGIN (PIXELS)]", left_margin); /* 16. Find number of pixels in right margin: * * [RIGHT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y", * (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 / * [CELL GRAN RND]),0)) * [CELL GRAN RND], * 0)) */ right_margin = margins ? rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN : 0.0; print_value(16, "[RIGHT MARGIN (PIXELS)]", right_margin); /* 17. Find total number of active pixels in image and left and right * margins: * * [TOTAL ACTIVE PIXELS] = [H PIXELS RND] + [LEFT MARGIN (PIXELS)] + * [RIGHT MARGIN (PIXELS)] */ total_active_pixels = h_pixels_rnd + left_margin + right_margin; print_value(17, "[TOTAL ACTIVE PIXELS]", total_active_pixels); /* 18. Find the ideal blanking duty cycle from the blanking duty cycle * equation: * * [IDEAL DUTY CYCLE] = [C'] - ([M']*[H PERIOD]/1000) */ ideal_duty_cycle = C_PRIME - (M_PRIME * h_period / 1000.0); print_value(18, "[IDEAL DUTY CYCLE]", ideal_duty_cycle); /* 19. Find the number of pixels in the blanking time to the nearest * double character cell: * * [H BLANK (PIXELS)] = (ROUND(([TOTAL ACTIVE PIXELS] * * [IDEAL DUTY CYCLE] / * (100-[IDEAL DUTY CYCLE]) / * (2*[CELL GRAN RND])), 0)) * * (2*[CELL GRAN RND]) */ h_blank = rint(total_active_pixels * ideal_duty_cycle / (100.0 - ideal_duty_cycle) / (2.0 * CELL_GRAN)) * (2.0 * CELL_GRAN); print_value(19, "[H BLANK (PIXELS)]", h_blank); /* 20. Find total number of pixels: * * [TOTAL PIXELS] = [TOTAL ACTIVE PIXELS] + [H BLANK (PIXELS)] */ total_pixels = total_active_pixels + h_blank; print_value(20, "[TOTAL PIXELS]", total_pixels); /* 21. Find pixel clock frequency: * * [PIXEL FREQ] = [TOTAL PIXELS] / [H PERIOD] */ pixel_freq = total_pixels / h_period; print_value(21, "[PIXEL FREQ]", pixel_freq); /* 22. Find horizontal frequency: * * [H FREQ] = 1000 / [H PERIOD] */ h_freq = 1000.0 / h_period; print_value(22, "[H FREQ]", h_freq); /* Stage 1 computations are now complete; I should really pass the results to another function and do the Stage 2 computations, but I only need a few more values so I'll just append the computations here for now */ /* 17. Find the number of pixels in the horizontal sync period: * * [H SYNC (PIXELS)] =(ROUND(([H SYNC%] / 100 * [TOTAL PIXELS] / * [CELL GRAN RND]),0))*[CELL GRAN RND] */ h_sync = rint(H_SYNC_PERCENT/100.0 * total_pixels / CELL_GRAN) * CELL_GRAN; print_value(17, "[H SYNC (PIXELS)]", h_sync); /* 18. Find the number of pixels in the horizontal front porch period: * * [H FRONT PORCH (PIXELS)] = ([H BLANK (PIXELS)]/2)-[H SYNC (PIXELS)] */ h_front_porch = (h_blank / 2.0) - h_sync; print_value(18, "[H FRONT PORCH (PIXELS)]", h_front_porch); /* 36. Find the number of lines in the odd front porch period: * * [V ODD FRONT PORCH(LINES)]=([MIN PORCH RND]+[INTERLACE]) */ v_odd_front_porch_lines = MIN_PORCH + interlace; print_value(36, "[V ODD FRONT PORCH(LINES)]", v_odd_front_porch_lines); /* finally, pack the results in the mode struct */ m->hr = (int) (h_pixels_rnd); m->hss = (int) (h_pixels_rnd + h_front_porch); m->hse = (int) (h_pixels_rnd + h_front_porch + h_sync); m->hfl = (int) (total_pixels); m->vr = (int) (v_lines_rnd); m->vss = (int) (v_lines_rnd + v_odd_front_porch_lines); m->vse = (int) (int) (v_lines_rnd + v_odd_front_porch_lines + V_SYNC_RQD); m->vfl = (int) (total_v_lines); m->pclk = pixel_freq; m->h_freq = h_freq; m->v_freq = freq; return (m); } /* * parse_command_line() - parse the command line and return an * alloced structure containing the results. On error print usage * and return NULL. */ options *parse_command_line (int argc, char *argv[]) { int n; options *o = (options *) calloc (1, sizeof (options)); if (argc < 4) goto bad_option; o->x = atoi (argv[1]); o->y = atoi (argv[2]); o->v_freq = atof (argv[3]); /* XXX should check for errors in the above */ n = 4; while (n < argc) { if ((strcmp (argv[n], "-v") == 0) || (strcmp (argv[n], "--verbose") == 0)) { global_verbose = 1; } else if ((strcmp (argv[n], "-f") == 0) || (strcmp (argv[n], "--fbmode") == 0)) { o->fbmode = 1; } else if ((strcmp (argv[n], "-x") == 0) || (strcmp (argv[n], "--xorgmode") == 0) || (strcmp (argv[n], "--xf86mode") == 0)) { o->xorgmode = 1; } else { goto bad_option; } n++; } /* if neither xorgmode nor fbmode were requested, default to xorgmode */ if (!o->fbmode && !o->xorgmode) o->xorgmode = 1; return (o); bad_option: fprintf (stderr, "\n"); fprintf (stderr, "usage: %s x y refresh [-v|--verbose] " "[-f|--fbmode] [-x|--xorgmode]\n", argv[0]); fprintf (stderr, "\n"); fprintf (stderr, " x : the desired horizontal " "resolution (required)\n"); fprintf (stderr, " y : the desired vertical " "resolution (required)\n"); fprintf (stderr, " refresh : the desired refresh " "rate (required)\n"); fprintf (stderr, " -v|--verbose : enable verbose printouts " "(traces each step of the computation)\n"); fprintf (stderr, " -f|--fbmode : output an fbset(8)-style mode " "description\n"); fprintf (stderr, " -x|--xorgmode : output an "__XSERVERNAME__"-style mode " "description (this is the default\n" " if no mode description is requested)\n"); fprintf (stderr, "\n"); free (o); return (NULL); } int main (int argc, char *argv[]) { mode *m; options *o; o = parse_command_line (argc, argv); if (!o) exit (1); m = vert_refresh (o->x, o->y, o->v_freq, 0, 0); if (!m) exit (1); if (o->xorgmode) print_xf86_mode(m); if (o->fbmode) print_fb_mode(m); return 0; }