1/* gtf.c  Generate mode timings using the GTF Timing Standard
2 *
3 * gcc gtf.c -o gtf -lm -Wall
4 *
5 * Copyright (c) 2001, Andy Ritger  aritger@nvidia.com
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * o Redistributions of source code must retain the above copyright
13 *   notice, this list of conditions and the following disclaimer.
14 * o Redistributions in binary form must reproduce the above copyright
15 *   notice, this list of conditions and the following disclaimer
16 *   in the documentation and/or other materials provided with the
17 *   distribution.
18 * o Neither the name of NVIDIA nor the names of its contributors
19 *   may be used to endorse or promote products derived from this
20 *   software without specific prior written permission.
21 *
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
25 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
26 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
27 * THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
29 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
31 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
33 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 *
36 *
37 *
38 * This program is based on the Generalized Timing Formula(GTF TM)
39 * Standard Version: 1.0, Revision: 1.0
40 *
41 * The GTF Document contains the following Copyright information:
42 *
43 * Copyright (c) 1994, 1995, 1996 - Video Electronics Standards
44 * Association. Duplication of this document within VESA member
45 * companies for review purposes is permitted. All other rights
46 * reserved.
47 *
48 * While every precaution has been taken in the preparation
49 * of this standard, the Video Electronics Standards Association and
50 * its contributors assume no responsibility for errors or omissions,
51 * and make no warranties, expressed or implied, of functionality
52 * of suitability for any purpose. The sample code contained within
53 * this standard may be used without restriction.
54 *
55 *
56 *
57 * The GTF EXCEL(TM) SPREADSHEET, a sample (and the definitive)
58 * implementation of the GTF Timing Standard, is available at:
59 *
60 * ftp://ftp.vesa.org/pub/GTF/GTF_V1R1.xls
61 *
62 *
63 *
64 * This program takes a desired resolution and vertical refresh rate,
65 * and computes mode timings according to the GTF Timing Standard.
66 * These mode timings can then be formatted as an XServer modeline
67 * or a mode description for use by fbset(8).
68 *
69 *
70 *
71 * NOTES:
72 *
73 * The GTF allows for computation of "margins" (the visible border
74 * surrounding the addressable video); on most non-overscan type
75 * systems, the margin period is zero.  I've implemented the margin
76 * computations but not enabled it because 1) I don't really have
77 * any experience with this, and 2) neither XServer modelines nor
78 * fbset fb.modes provide an obvious way for margin timings to be
79 * included in their mode descriptions (needs more investigation).
80 *
81 * The GTF provides for computation of interlaced mode timings;
82 * I've implemented the computations but not enabled them, yet.
83 * I should probably enable and test this at some point.
84 *
85 *
86 *
87 * TODO:
88 *
89 * o Add support for interlaced modes.
90 *
91 * o Implement the other portions of the GTF: compute mode timings
92 *   given either the desired pixel clock or the desired horizontal
93 *   frequency.
94 *
95 * o It would be nice if this were more general purpose to do things
96 *   outside the scope of the GTF: like generate double scan mode
97 *   timings, for example.
98 *
99 * o Printing digits to the right of the decimal point when the
100 *   digits are 0 annoys me.
101 *
102 * o Error checking.
103 *
104 */
105
106#ifdef HAVE_XORG_CONFIG_H
107#include <xorg-config.h>
108#endif
109
110#include <stdio.h>
111#include <stdlib.h>
112#include <string.h>
113#include <math.h>
114
115#define MARGIN_PERCENT    1.8   /* % of active vertical image                */
116#define CELL_GRAN         8.0   /* assumed character cell granularity        */
117#define MIN_PORCH         1     /* minimum front porch                       */
118#define V_SYNC_RQD        3     /* width of vsync in lines                   */
119#define H_SYNC_PERCENT    8.0   /* width of hsync as % of total line         */
120#define MIN_VSYNC_PLUS_BP 550.0 /* min time of vsync + back porch (microsec) */
121#define M                 600.0 /* blanking formula gradient                 */
122#define C                 40.0  /* blanking formula offset                   */
123#define K                 128.0 /* blanking formula scaling factor           */
124#define J                 20.0  /* blanking formula scaling factor           */
125
126/* C' and M' are part of the Blanking Duty Cycle computation */
127
128#define C_PRIME           (((C - J) * K/256.0) + J)
129#define M_PRIME           (K/256.0 * M)
130
131/* struct definitions */
132
133typedef struct __mode {
134    int hr, hss, hse, hfl;
135    int vr, vss, vse, vfl;
136    float pclk, h_freq, v_freq;
137} mode;
138
139typedef struct __options {
140    int x, y;
141    int xorgmode, fbmode;
142    float v_freq;
143} options;
144
145/* prototypes */
146
147void print_value(int n, const char *name, float val);
148void print_xf86_mode(mode * m);
149void print_fb_mode(mode * m);
150mode *vert_refresh(int h_pixels, int v_lines, float freq,
151                   int interlaced, int margins);
152options *parse_command_line(int argc, char *argv[]);
153
154/*
155 * print_value() - print the result of the named computation; this is
156 * useful when comparing against the GTF EXCEL spreadsheet.
157 */
158
159int global_verbose = 0;
160
161void
162print_value(int n, const char *name, float val)
163{
164    if (global_verbose) {
165        printf("%2d: %-27s: %15f\n", n, name, val);
166    }
167}
168
169/* print_xf86_mode() - print the XServer modeline, given mode timings. */
170
171void
172print_xf86_mode(mode * m)
173{
174    printf("\n");
175    printf("  # %dx%d @ %.2f Hz (GTF) hsync: %.2f kHz; pclk: %.2f MHz\n",
176           m->hr, m->vr, m->v_freq, m->h_freq, m->pclk);
177
178    printf("  Modeline \"%dx%d_%.2f\"  %.2f"
179           "  %d %d %d %d"
180           "  %d %d %d %d"
181           "  -HSync +Vsync\n\n",
182           m->hr, m->vr, m->v_freq, m->pclk,
183           m->hr, m->hss, m->hse, m->hfl, m->vr, m->vss, m->vse, m->vfl);
184
185}
186
187/*
188 * print_fb_mode() - print a mode description in fbset(8) format;
189 * see the fb.modes(8) manpage.  The timing description used in
190 * this is rather odd; they use "left and right margin" to refer
191 * to the portion of the hblank before and after the sync pulse
192 * by conceptually wrapping the portion of the blank after the pulse
193 * to infront of the visible region; ie:
194 *
195 *
196 * Timing description I'm accustomed to:
197 *
198 *
199 *
200 *     <--------1--------> <--2--> <--3--> <--4-->
201 *                                _________
202 *    |-------------------|_______|       |_______
203 *
204 *                        R       SS      SE     FL
205 *
206 * 1: visible image
207 * 2: blank before sync (aka front porch)
208 * 3: sync pulse
209 * 4: blank after sync (aka back porch)
210 * R: Resolution
211 * SS: Sync Start
212 * SE: Sync End
213 * FL: Frame Length
214 *
215 *
216 * But the fb.modes format is:
217 *
218 *
219 *    <--4--> <--------1--------> <--2--> <--3-->
220 *                                       _________
221 *    _______|-------------------|_______|       |
222 *
223 * The fb.modes(8) manpage refers to <4> and <2> as the left and
224 * right "margin" (as well as upper and lower margin in the vertical
225 * direction) -- note that this has nothing to do with the term
226 * "margin" used in the GTF Timing Standard.
227 *
228 * XXX always prints the 32 bit mode -- should I provide a command
229 * line option to specify the bpp?  It's simple enough for a user
230 * to edit the mode description after it's generated.
231 */
232
233void
234print_fb_mode(mode * m)
235{
236    printf("\n");
237    printf("mode \"%dx%d %.2fHz 32bit (GTF)\"\n", m->hr, m->vr, m->v_freq);
238    printf("    # PCLK: %.2f MHz, H: %.2f kHz, V: %.2f Hz\n",
239           m->pclk, m->h_freq, m->v_freq);
240    printf("    geometry %d %d %d %d 32\n", m->hr, m->vr, m->hr, m->vr);
241    printf("    timings %d %d %d %d %d %d %d\n", (int)lrint(1000000.0 / m->pclk),       /* pixclock in picoseconds */
242           m->hfl - m->hse,     /* left margin (in pixels) */
243           m->hss - m->hr,      /* right margin (in pixels) */
244           m->vfl - m->vse,     /* upper margin (in pixel lines) */
245           m->vss - m->vr,      /* lower margin (in pixel lines) */
246           m->hse - m->hss,     /* horizontal sync length (pixels) */
247           m->vse - m->vss);    /* vert sync length (pixel lines) */
248    printf("    hsync low\n");
249    printf("    vsync high\n");
250    printf("endmode\n\n");
251
252}
253
254/*
255 * vert_refresh() - as defined by the GTF Timing Standard, compute the
256 * Stage 1 Parameters using the vertical refresh frequency.  In other
257 * words: input a desired resolution and desired refresh rate, and
258 * output the GTF mode timings.
259 *
260 * XXX All the code is in place to compute interlaced modes, but I don't
261 * feel like testing it right now.
262 *
263 * XXX margin computations are implemented but not tested (nor used by
264 * XServer of fbset mode descriptions, from what I can tell).
265 */
266
267mode *
268vert_refresh(int h_pixels, int v_lines, float freq, int interlaced, int margins)
269{
270    float h_pixels_rnd;
271    float v_lines_rnd;
272    float v_field_rate_rqd;
273    float top_margin;
274    float bottom_margin;
275    float interlace;
276    float h_period_est;
277    float vsync_plus_bp;
278    float v_back_porch;
279    float total_v_lines;
280    float v_field_rate_est;
281    float h_period;
282    float v_field_rate;
283    float v_frame_rate;
284    float left_margin;
285    float right_margin;
286    float total_active_pixels;
287    float ideal_duty_cycle;
288    float h_blank;
289    float total_pixels;
290    float pixel_freq;
291    float h_freq;
292
293    float h_sync;
294    float h_front_porch;
295    float v_odd_front_porch_lines;
296
297    mode *m = (mode *) malloc(sizeof(mode));
298
299    /*  1. In order to give correct results, the number of horizontal
300     *  pixels requested is first processed to ensure that it is divisible
301     *  by the character size, by rounding it to the nearest character
302     *  cell boundary:
303     *
304     *  [H PIXELS RND] = ((ROUND([H PIXELS]/[CELL GRAN RND],0))*[CELLGRAN RND])
305     */
306
307    h_pixels_rnd = rint((float) h_pixels / CELL_GRAN) * CELL_GRAN;
308
309    print_value(1, "[H PIXELS RND]", h_pixels_rnd);
310
311    /*  2. If interlace is requested, the number of vertical lines assumed
312     *  by the calculation must be halved, as the computation calculates
313     *  the number of vertical lines per field. In either case, the
314     *  number of lines is rounded to the nearest integer.
315     *
316     *  [V LINES RND] = IF([INT RQD?]="y", ROUND([V LINES]/2,0),
317     *                                     ROUND([V LINES],0))
318     */
319
320    v_lines_rnd = interlaced ?
321        rint((float) v_lines) / 2.0 : rint((float) v_lines);
322
323    print_value(2, "[V LINES RND]", v_lines_rnd);
324
325    /*  3. Find the frame rate required:
326     *
327     *  [V FIELD RATE RQD] = IF([INT RQD?]="y", [I/P FREQ RQD]*2,
328     *                                          [I/P FREQ RQD])
329     */
330
331    v_field_rate_rqd = interlaced ? (freq * 2.0) : (freq);
332
333    print_value(3, "[V FIELD RATE RQD]", v_field_rate_rqd);
334
335    /*  4. Find number of lines in Top margin:
336     *
337     *  [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y",
338     *          ROUND(([MARGIN%]/100*[V LINES RND]),0),
339     *          0)
340     */
341
342    top_margin = margins ? rint(MARGIN_PERCENT / 100.0 * v_lines_rnd) : (0.0);
343
344    print_value(4, "[TOP MARGIN (LINES)]", top_margin);
345
346    /*  5. Find number of lines in Bottom margin:
347     *
348     *  [BOT MARGIN (LINES)] = IF([MARGINS RQD?]="Y",
349     *          ROUND(([MARGIN%]/100*[V LINES RND]),0),
350     *          0)
351     */
352
353    bottom_margin =
354        margins ? rint(MARGIN_PERCENT / 100.0 * v_lines_rnd) : (0.0);
355
356    print_value(5, "[BOT MARGIN (LINES)]", bottom_margin);
357
358    /*  6. If interlace is required, then set variable [INTERLACE]=0.5:
359     *
360     *  [INTERLACE]=(IF([INT RQD?]="y",0.5,0))
361     */
362
363    interlace = interlaced ? 0.5 : 0.0;
364
365    print_value(6, "[INTERLACE]", interlace);
366
367    /*  7. Estimate the Horizontal period
368     *
369     *  [H PERIOD EST] = ((1/[V FIELD RATE RQD]) - [MIN VSYNC+BP]/1000000) /
370     *                    ([V LINES RND] + (2*[TOP MARGIN (LINES)]) +
371     *                     [MIN PORCH RND]+[INTERLACE]) * 1000000
372     */
373
374    h_period_est = (((1.0 / v_field_rate_rqd) - (MIN_VSYNC_PLUS_BP / 1000000.0))
375                    / (v_lines_rnd + (2 * top_margin) + MIN_PORCH + interlace)
376                    * 1000000.0);
377
378    print_value(7, "[H PERIOD EST]", h_period_est);
379
380    /*  8. Find the number of lines in V sync + back porch:
381     *
382     *  [V SYNC+BP] = ROUND(([MIN VSYNC+BP]/[H PERIOD EST]),0)
383     */
384
385    vsync_plus_bp = rint(MIN_VSYNC_PLUS_BP / h_period_est);
386
387    print_value(8, "[V SYNC+BP]", vsync_plus_bp);
388
389    /*  9. Find the number of lines in V back porch alone:
390     *
391     *  [V BACK PORCH] = [V SYNC+BP] - [V SYNC RND]
392     *
393     *  XXX is "[V SYNC RND]" a typo? should be [V SYNC RQD]?
394     */
395
396    v_back_porch = vsync_plus_bp - V_SYNC_RQD;
397
398    print_value(9, "[V BACK PORCH]", v_back_porch);
399
400    /*  10. Find the total number of lines in Vertical field period:
401     *
402     *  [TOTAL V LINES] = [V LINES RND] + [TOP MARGIN (LINES)] +
403     *                    [BOT MARGIN (LINES)] + [V SYNC+BP] + [INTERLACE] +
404     *                    [MIN PORCH RND]
405     */
406
407    total_v_lines = v_lines_rnd + top_margin + bottom_margin + vsync_plus_bp +
408        interlace + MIN_PORCH;
409
410    print_value(10, "[TOTAL V LINES]", total_v_lines);
411
412    /*  11. Estimate the Vertical field frequency:
413     *
414     *  [V FIELD RATE EST] = 1 / [H PERIOD EST] / [TOTAL V LINES] * 1000000
415     */
416
417    v_field_rate_est = 1.0 / h_period_est / total_v_lines * 1000000.0;
418
419    print_value(11, "[V FIELD RATE EST]", v_field_rate_est);
420
421    /*  12. Find the actual horizontal period:
422     *
423     *  [H PERIOD] = [H PERIOD EST] / ([V FIELD RATE RQD] / [V FIELD RATE EST])
424     */
425
426    h_period = h_period_est / (v_field_rate_rqd / v_field_rate_est);
427
428    print_value(12, "[H PERIOD]", h_period);
429
430    /*  13. Find the actual Vertical field frequency:
431     *
432     *  [V FIELD RATE] = 1 / [H PERIOD] / [TOTAL V LINES] * 1000000
433     */
434
435    v_field_rate = 1.0 / h_period / total_v_lines * 1000000.0;
436
437    print_value(13, "[V FIELD RATE]", v_field_rate);
438
439    /*  14. Find the Vertical frame frequency:
440     *
441     *  [V FRAME RATE] = (IF([INT RQD?]="y", [V FIELD RATE]/2, [V FIELD RATE]))
442     */
443
444    v_frame_rate = interlaced ? v_field_rate / 2.0 : v_field_rate;
445
446    print_value(14, "[V FRAME RATE]", v_frame_rate);
447
448    /*  15. Find number of pixels in left margin:
449     *
450     *  [LEFT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y",
451     *          (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 /
452     *                   [CELL GRAN RND]),0)) * [CELL GRAN RND],
453     *          0))
454     */
455
456    left_margin = margins ?
457        rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN :
458        0.0;
459
460    print_value(15, "[LEFT MARGIN (PIXELS)]", left_margin);
461
462    /*  16. Find number of pixels in right margin:
463     *
464     *  [RIGHT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y",
465     *          (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 /
466     *                   [CELL GRAN RND]),0)) * [CELL GRAN RND],
467     *          0))
468     */
469
470    right_margin = margins ?
471        rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN :
472        0.0;
473
474    print_value(16, "[RIGHT MARGIN (PIXELS)]", right_margin);
475
476    /*  17. Find total number of active pixels in image and left and right
477     *  margins:
478     *
479     *  [TOTAL ACTIVE PIXELS] = [H PIXELS RND] + [LEFT MARGIN (PIXELS)] +
480     *                          [RIGHT MARGIN (PIXELS)]
481     */
482
483    total_active_pixels = h_pixels_rnd + left_margin + right_margin;
484
485    print_value(17, "[TOTAL ACTIVE PIXELS]", total_active_pixels);
486
487    /*  18. Find the ideal blanking duty cycle from the blanking duty cycle
488     *  equation:
489     *
490     *  [IDEAL DUTY CYCLE] = [C'] - ([M']*[H PERIOD]/1000)
491     */
492
493    ideal_duty_cycle = C_PRIME - (M_PRIME * h_period / 1000.0);
494
495    print_value(18, "[IDEAL DUTY CYCLE]", ideal_duty_cycle);
496
497    /*  19. Find the number of pixels in the blanking time to the nearest
498     *  double character cell:
499     *
500     *  [H BLANK (PIXELS)] = (ROUND(([TOTAL ACTIVE PIXELS] *
501     *                               [IDEAL DUTY CYCLE] /
502     *                               (100-[IDEAL DUTY CYCLE]) /
503     *                               (2*[CELL GRAN RND])), 0))
504     *                       * (2*[CELL GRAN RND])
505     */
506
507    h_blank = rint(total_active_pixels *
508                   ideal_duty_cycle /
509                   (100.0 - ideal_duty_cycle) /
510                   (2.0 * CELL_GRAN)) * (2.0 * CELL_GRAN);
511
512    print_value(19, "[H BLANK (PIXELS)]", h_blank);
513
514    /*  20. Find total number of pixels:
515     *
516     *  [TOTAL PIXELS] = [TOTAL ACTIVE PIXELS] + [H BLANK (PIXELS)]
517     */
518
519    total_pixels = total_active_pixels + h_blank;
520
521    print_value(20, "[TOTAL PIXELS]", total_pixels);
522
523    /*  21. Find pixel clock frequency:
524     *
525     *  [PIXEL FREQ] = [TOTAL PIXELS] / [H PERIOD]
526     */
527
528    pixel_freq = total_pixels / h_period;
529
530    print_value(21, "[PIXEL FREQ]", pixel_freq);
531
532    /*  22. Find horizontal frequency:
533     *
534     *  [H FREQ] = 1000 / [H PERIOD]
535     */
536
537    h_freq = 1000.0 / h_period;
538
539    print_value(22, "[H FREQ]", h_freq);
540
541    /* Stage 1 computations are now complete; I should really pass
542       the results to another function and do the Stage 2
543       computations, but I only need a few more values so I'll just
544       append the computations here for now */
545
546    /*  17. Find the number of pixels in the horizontal sync period:
547     *
548     *  [H SYNC (PIXELS)] =(ROUND(([H SYNC%] / 100 * [TOTAL PIXELS] /
549     *                             [CELL GRAN RND]),0))*[CELL GRAN RND]
550     */
551
552    h_sync =
553        rint(H_SYNC_PERCENT / 100.0 * total_pixels / CELL_GRAN) * CELL_GRAN;
554
555    print_value(17, "[H SYNC (PIXELS)]", h_sync);
556
557    /*  18. Find the number of pixels in the horizontal front porch period:
558     *
559     *  [H FRONT PORCH (PIXELS)] = ([H BLANK (PIXELS)]/2)-[H SYNC (PIXELS)]
560     */
561
562    h_front_porch = (h_blank / 2.0) - h_sync;
563
564    print_value(18, "[H FRONT PORCH (PIXELS)]", h_front_porch);
565
566    /*  36. Find the number of lines in the odd front porch period:
567     *
568     *  [V ODD FRONT PORCH(LINES)]=([MIN PORCH RND]+[INTERLACE])
569     */
570
571    v_odd_front_porch_lines = MIN_PORCH + interlace;
572
573    print_value(36, "[V ODD FRONT PORCH(LINES)]", v_odd_front_porch_lines);
574
575    /* finally, pack the results in the mode struct */
576
577    m->hr = (int) (h_pixels_rnd);
578    m->hss = (int) (h_pixels_rnd + h_front_porch);
579    m->hse = (int) (h_pixels_rnd + h_front_porch + h_sync);
580    m->hfl = (int) (total_pixels);
581
582    m->vr = (int) (v_lines_rnd);
583    m->vss = (int) (v_lines_rnd + v_odd_front_porch_lines);
584    m->vse = (int) (int) (v_lines_rnd + v_odd_front_porch_lines + V_SYNC_RQD);
585    m->vfl = (int) (total_v_lines);
586
587    m->pclk = pixel_freq;
588    m->h_freq = h_freq;
589    m->v_freq = freq;
590
591    return m;
592
593}
594
595/*
596 * parse_command_line() - parse the command line and return an
597 * alloced structure containing the results.  On error print usage
598 * and return NULL.
599 */
600
601options *
602parse_command_line(int argc, char *argv[])
603{
604    int n;
605
606    options *o = (options *) calloc(1, sizeof(options));
607
608    if (argc < 4)
609        goto bad_option;
610
611    o->x = atoi(argv[1]);
612    o->y = atoi(argv[2]);
613    o->v_freq = atof(argv[3]);
614
615    /* XXX should check for errors in the above */
616
617    n = 4;
618
619    while (n < argc) {
620        if ((strcmp(argv[n], "-v") == 0) || (strcmp(argv[n], "--verbose") == 0)) {
621            global_verbose = 1;
622        }
623        else if ((strcmp(argv[n], "-f") == 0) ||
624                 (strcmp(argv[n], "--fbmode") == 0)) {
625            o->fbmode = 1;
626        }
627        else if ((strcmp(argv[n], "-x") == 0) ||
628                 (strcmp(argv[n], "--xorgmode") == 0) ||
629                 (strcmp(argv[n], "--xf86mode") == 0)) {
630            o->xorgmode = 1;
631        }
632        else {
633            goto bad_option;
634        }
635
636        n++;
637    }
638
639    /* if neither xorgmode nor fbmode were requested, default to
640       xorgmode */
641
642    if (!o->fbmode && !o->xorgmode)
643        o->xorgmode = 1;
644
645    return o;
646
647 bad_option:
648
649    fprintf(stderr, "\n");
650    fprintf(stderr, "usage: %s x y refresh [-v|--verbose] "
651            "[-f|--fbmode] [-x|--xorgmode]\n", argv[0]);
652
653    fprintf(stderr, "\n");
654
655    fprintf(stderr, "            x : the desired horizontal "
656            "resolution (required)\n");
657    fprintf(stderr, "            y : the desired vertical "
658            "resolution (required)\n");
659    fprintf(stderr, "      refresh : the desired refresh " "rate (required)\n");
660    fprintf(stderr, " -v|--verbose : enable verbose printouts "
661            "(traces each step of the computation)\n");
662    fprintf(stderr, "  -f|--fbmode : output an fbset(8)-style mode "
663            "description\n");
664    fprintf(stderr, " -x|--xorgmode : output an " __XSERVERNAME__ "-style mode "
665            "description (this is the default\n"
666            "                if no mode description is requested)\n");
667
668    fprintf(stderr, "\n");
669
670    free(o);
671    return NULL;
672
673}
674
675int
676main(int argc, char *argv[])
677{
678    mode *m;
679    options *o;
680
681    o = parse_command_line(argc, argv);
682    if (!o)
683        exit(1);
684
685    m = vert_refresh(o->x, o->y, o->v_freq, 0, 0);
686    if (!m)
687        exit(1);
688
689    if (o->xorgmode)
690        print_xf86_mode(m);
691
692    if (o->fbmode)
693        print_fb_mode(m);
694
695    free(m);
696
697    return 0;
698
699}
700