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xserver/hw/xfree86/utils/gtf/gtf.c

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/* 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, const 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, const 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)lrint(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);
free(m);
return 0;
}
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