Line data Source code
1 : /* $NetBSD: vesagtf.c,v 1.1 2006/05/11 01:49:53 gdamore Exp $ */
2 :
3 : /*-
4 : * Copyright (c) 2006 Itronix Inc.
5 : * All rights reserved.
6 : *
7 : * Written by Garrett D'Amore for Itronix Inc.
8 : *
9 : * Redistribution and use in source and binary forms, with or without
10 : * modification, are permitted provided that the following conditions
11 : * are met:
12 : * 1. Redistributions of source code must retain the above copyright
13 : * notice, this list of conditions and the following disclaimer.
14 : * 2. Redistributions in binary form must reproduce the above copyright
15 : * notice, this list of conditions and the following disclaimer in the
16 : * documentation and/or other materials provided with the distribution.
17 : * 3. The name of Itronix Inc. may not be used to endorse
18 : * or promote products derived from this software without specific
19 : * prior written permission.
20 : *
21 : * THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND ANY EXPRESS
22 : * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23 : * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 : * ARE DISCLAIMED. IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY
25 : * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 : * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27 : * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 : * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 : * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30 : * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31 : * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 : */
33 :
34 : /*
35 : * This was derived from a userland GTF program supplied by NVIDIA.
36 : * NVIDIA's original boilerplate follows.
37 : *
38 : * Note that I have heavily modified the program for use in the EDID
39 : * kernel code for NetBSD, including removing the use of floating
40 : * point operations and making significant adjustments to minimize
41 : * error propogation while operating with integer only math.
42 : *
43 : * This has required the use of 64-bit integers in a few places, but
44 : * the upshot is that for a calculation of 1920x1200x85 (as an
45 : * example), the error deviates by only ~.004% relative to the
46 : * floating point version. This error is *well* within VESA
47 : * tolerances.
48 : */
49 :
50 : /*
51 : * Copyright (c) 2001, Andy Ritger aritger@nvidia.com
52 : * All rights reserved.
53 : *
54 : * Redistribution and use in source and binary forms, with or without
55 : * modification, are permitted provided that the following conditions
56 : * are met:
57 : *
58 : * o Redistributions of source code must retain the above copyright
59 : * notice, this list of conditions and the following disclaimer.
60 : * o Redistributions in binary form must reproduce the above copyright
61 : * notice, this list of conditions and the following disclaimer
62 : * in the documentation and/or other materials provided with the
63 : * distribution.
64 : * o Neither the name of NVIDIA nor the names of its contributors
65 : * may be used to endorse or promote products derived from this
66 : * software without specific prior written permission.
67 : *
68 : *
69 : * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
70 : * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
71 : * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
72 : * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
73 : * THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
74 : * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
75 : * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
76 : * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
77 : * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
78 : * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
79 : * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
80 : * POSSIBILITY OF SUCH DAMAGE.
81 : *
82 : *
83 : *
84 : * This program is based on the Generalized Timing Formula(GTF TM)
85 : * Standard Version: 1.0, Revision: 1.0
86 : *
87 : * The GTF Document contains the following Copyright information:
88 : *
89 : * Copyright (c) 1994, 1995, 1996 - Video Electronics Standards
90 : * Association. Duplication of this document within VESA member
91 : * companies for review purposes is permitted. All other rights
92 : * reserved.
93 : *
94 : * While every precaution has been taken in the preparation
95 : * of this standard, the Video Electronics Standards Association and
96 : * its contributors assume no responsibility for errors or omissions,
97 : * and make no warranties, expressed or implied, of functionality
98 : * of suitability for any purpose. The sample code contained within
99 : * this standard may be used without restriction.
100 : *
101 : *
102 : *
103 : * The GTF EXCEL(TM) SPREADSHEET, a sample (and the definitive)
104 : * implementation of the GTF Timing Standard, is available at:
105 : *
106 : * ftp://ftp.vesa.org/pub/GTF/GTF_V1R1.xls
107 : *
108 : *
109 : *
110 : * This program takes a desired resolution and vertical refresh rate,
111 : * and computes mode timings according to the GTF Timing Standard.
112 : * These mode timings can then be formatted as an XFree86 modeline
113 : * or a mode description for use by fbset(8).
114 : *
115 : *
116 : *
117 : * NOTES:
118 : *
119 : * The GTF allows for computation of "margins" (the visible border
120 : * surrounding the addressable video); on most non-overscan type
121 : * systems, the margin period is zero. I've implemented the margin
122 : * computations but not enabled it because 1) I don't really have
123 : * any experience with this, and 2) neither XFree86 modelines nor
124 : * fbset fb.modes provide an obvious way for margin timings to be
125 : * included in their mode descriptions (needs more investigation).
126 : *
127 : * The GTF provides for computation of interlaced mode timings;
128 : * I've implemented the computations but not enabled them, yet.
129 : * I should probably enable and test this at some point.
130 : *
131 : *
132 : *
133 : * TODO:
134 : *
135 : * o Add support for interlaced modes.
136 : *
137 : * o Implement the other portions of the GTF: compute mode timings
138 : * given either the desired pixel clock or the desired horizontal
139 : * frequency.
140 : *
141 : * o It would be nice if this were more general purpose to do things
142 : * outside the scope of the GTF: like generate double scan mode
143 : * timings, for example.
144 : *
145 : * o Printing digits to the right of the decimal point when the
146 : * digits are 0 annoys me.
147 : *
148 : * o Error checking.
149 : *
150 : */
151 :
152 :
153 : #ifdef _KERNEL
154 : #include <sys/param.h>
155 : #include <sys/systm.h>
156 : #include <dev/videomode/videomode.h>
157 : #include <dev/videomode/vesagtf.h>
158 : #else
159 : #include <sys/types.h>
160 : #include "videomode.h"
161 : #include "vesagtf.h"
162 : #include <stdio.h>
163 : #include <stdlib.h>
164 : void print_xf86_mode(struct videomode *m);
165 : #endif
166 :
167 : #define CELL_GRAN 8 /* assumed character cell granularity */
168 :
169 : /* C' and M' are part of the Blanking Duty Cycle computation */
170 : /*
171 : * #define C_PRIME (((C - J) * K/256.0) + J)
172 : * #define M_PRIME (K/256.0 * M)
173 : */
174 :
175 : /*
176 : * C' and M' multiplied by 256 to give integer math. Make sure to
177 : * scale results using these back down, appropriately.
178 : */
179 : #define C_PRIME256(p) (((p->C - p->J) * p->K) + (p->J * 256))
180 : #define M_PRIME256(p) (p->K * p->M)
181 :
182 : #define DIVIDE(x,y) (((x) + ((y) / 2)) / (y))
183 :
184 : /*
185 : * print_value() - print the result of the named computation; this is
186 : * useful when comparing against the GTF EXCEL spreadsheet.
187 : */
188 :
189 : #ifdef GTFDEBUG
190 :
191 : void
192 : print_value(int n, const char *name, unsigned val)
193 : {
194 : printf("%2d: %-27s: %u\n", n, name, val);
195 : }
196 : #else
197 : #define print_value(n, name, val)
198 : #endif
199 :
200 :
201 : /*
202 : * vert_refresh() - as defined by the GTF Timing Standard, compute the
203 : * Stage 1 Parameters using the vertical refresh frequency. In other
204 : * words: input a desired resolution and desired refresh rate, and
205 : * output the GTF mode timings.
206 : *
207 : * XXX All the code is in place to compute interlaced modes, but I don't
208 : * feel like testing it right now.
209 : *
210 : * XXX margin computations are implemented but not tested (nor used by
211 : * XFree86 of fbset mode descriptions, from what I can tell).
212 : */
213 :
214 : void
215 0 : vesagtf_mode_params(unsigned h_pixels, unsigned v_lines, unsigned freq,
216 : struct vesagtf_params *params, int flags, struct videomode *vmp)
217 : {
218 : unsigned v_field_rqd;
219 : unsigned top_margin;
220 : unsigned bottom_margin;
221 : unsigned interlace;
222 : uint64_t h_period_est;
223 : unsigned vsync_plus_bp;
224 : unsigned v_back_porch;
225 : unsigned total_v_lines;
226 : uint64_t v_field_est;
227 : uint64_t h_period;
228 : unsigned v_field_rate;
229 : unsigned v_frame_rate;
230 : unsigned left_margin;
231 : unsigned right_margin;
232 : unsigned total_active_pixels;
233 : uint64_t ideal_duty_cycle;
234 : unsigned h_blank;
235 : unsigned total_pixels;
236 : unsigned pixel_freq;
237 :
238 : unsigned h_sync;
239 : unsigned h_front_porch;
240 : unsigned v_odd_front_porch_lines;
241 :
242 : #ifdef GTFDEBUG
243 : unsigned h_freq;
244 : #endif
245 :
246 : /* 1. In order to give correct results, the number of horizontal
247 : * pixels requested is first processed to ensure that it is divisible
248 : * by the character size, by rounding it to the nearest character
249 : * cell boundary:
250 : *
251 : * [H PIXELS RND] = ((ROUND([H PIXELS]/[CELL GRAN RND],0))*[CELLGRAN RND])
252 : */
253 :
254 0 : h_pixels = DIVIDE(h_pixels, CELL_GRAN) * CELL_GRAN;
255 :
256 : print_value(1, "[H PIXELS RND]", h_pixels);
257 :
258 :
259 : /* 2. If interlace is requested, the number of vertical lines assumed
260 : * by the calculation must be halved, as the computation calculates
261 : * the number of vertical lines per field. In either case, the
262 : * number of lines is rounded to the nearest integer.
263 : *
264 : * [V LINES RND] = IF([INT RQD?]="y", ROUND([V LINES]/2,0),
265 : * ROUND([V LINES],0))
266 : */
267 :
268 0 : v_lines = (flags & VESAGTF_FLAG_ILACE) ? DIVIDE(v_lines, 2) : v_lines;
269 :
270 : print_value(2, "[V LINES RND]", v_lines);
271 :
272 :
273 : /* 3. Find the frame rate required:
274 : *
275 : * [V FIELD RATE RQD] = IF([INT RQD?]="y", [I/P FREQ RQD]*2,
276 : * [I/P FREQ RQD])
277 : */
278 :
279 0 : v_field_rqd = (flags & VESAGTF_FLAG_ILACE) ? (freq * 2) : (freq);
280 :
281 : print_value(3, "[V FIELD RATE RQD]", v_field_rqd);
282 :
283 :
284 : /* 4. Find number of lines in Top margin:
285 : * 5. Find number of lines in Bottom margin:
286 : *
287 : * [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y",
288 : * ROUND(([MARGIN%]/100*[V LINES RND]),0),
289 : * 0)
290 : *
291 : * Ditto for bottom margin. Note that instead of %, we use PPT, which
292 : * is parts per thousand. This helps us with integer math.
293 : */
294 :
295 0 : top_margin = bottom_margin = (flags & VESAGTF_FLAG_MARGINS) ?
296 0 : DIVIDE(v_lines * params->margin_ppt, 1000) : 0;
297 :
298 : print_value(4, "[TOP MARGIN (LINES)]", top_margin);
299 : print_value(5, "[BOT MARGIN (LINES)]", bottom_margin);
300 :
301 :
302 : /* 6. If interlace is required, then set variable [INTERLACE]=0.5:
303 : *
304 : * [INTERLACE]=(IF([INT RQD?]="y",0.5,0))
305 : *
306 : * To make this integer friendly, we use some special hacks in step
307 : * 7 below. Please read those comments to understand why I am using
308 : * a whole number of 1.0 instead of 0.5 here.
309 : */
310 0 : interlace = (flags & VESAGTF_FLAG_ILACE) ? 1 : 0;
311 :
312 : print_value(6, "[2*INTERLACE]", interlace);
313 :
314 :
315 : /* 7. Estimate the Horizontal period
316 : *
317 : * [H PERIOD EST] = ((1/[V FIELD RATE RQD]) - [MIN VSYNC+BP]/1000000) /
318 : * ([V LINES RND] + (2*[TOP MARGIN (LINES)]) +
319 : * [MIN PORCH RND]+[INTERLACE]) * 1000000
320 : *
321 : * To make it integer friendly, we pre-multiply the 1000000 to get to
322 : * usec. This gives us:
323 : *
324 : * [H PERIOD EST] = ((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP]) /
325 : * ([V LINES RND] + (2 * [TOP MARGIN (LINES)]) +
326 : * [MIN PORCH RND]+[INTERLACE])
327 : *
328 : * The other problem is that the interlace value is wrong. To get
329 : * the interlace to a whole number, we multiply both the numerator and
330 : * divisor by 2, so we can use a value of either 1 or 0 for the interlace
331 : * factor.
332 : *
333 : * This gives us:
334 : *
335 : * [H PERIOD EST] = ((2*((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP])) /
336 : * (2*([V LINES RND] + (2*[TOP MARGIN (LINES)]) +
337 : * [MIN PORCH RND]) + [2*INTERLACE]))
338 : *
339 : * Finally we multiply by another 1000, to get value in picosec.
340 : * Why picosec? To minimize rounding errors. Gotta love integer
341 : * math and error propogation.
342 : */
343 :
344 0 : h_period_est = DIVIDE(((DIVIDE(2000000000000ULL, v_field_rqd)) -
345 : (2000000 * params->min_vsbp)),
346 : ((2 * (v_lines + (2 * top_margin) + params->min_porch)) + interlace));
347 :
348 : print_value(7, "[H PERIOD EST (ps)]", h_period_est);
349 :
350 :
351 : /* 8. Find the number of lines in V sync + back porch:
352 : *
353 : * [V SYNC+BP] = ROUND(([MIN VSYNC+BP]/[H PERIOD EST]),0)
354 : *
355 : * But recall that h_period_est is in psec. So multiply by 1000000.
356 : */
357 :
358 0 : vsync_plus_bp = DIVIDE(params->min_vsbp * 1000000, h_period_est);
359 :
360 : print_value(8, "[V SYNC+BP]", vsync_plus_bp);
361 :
362 :
363 : /* 9. Find the number of lines in V back porch alone:
364 : *
365 : * [V BACK PORCH] = [V SYNC+BP] - [V SYNC RND]
366 : *
367 : * XXX is "[V SYNC RND]" a typo? should be [V SYNC RQD]?
368 : */
369 :
370 0 : v_back_porch = vsync_plus_bp - params->vsync_rqd;
371 :
372 : print_value(9, "[V BACK PORCH]", v_back_porch);
373 :
374 :
375 : /* 10. Find the total number of lines in Vertical field period:
376 : *
377 : * [TOTAL V LINES] = [V LINES RND] + [TOP MARGIN (LINES)] +
378 : * [BOT MARGIN (LINES)] + [V SYNC+BP] + [INTERLACE] +
379 : * [MIN PORCH RND]
380 : */
381 :
382 0 : total_v_lines = v_lines + top_margin + bottom_margin + vsync_plus_bp +
383 0 : interlace + params->min_porch;
384 :
385 : print_value(10, "[TOTAL V LINES]", total_v_lines);
386 :
387 :
388 : /* 11. Estimate the Vertical field frequency:
389 : *
390 : * [V FIELD RATE EST] = 1 / [H PERIOD EST] / [TOTAL V LINES] * 1000000
391 : *
392 : * Again, we want to pre multiply by 10^9 to convert for nsec, thereby
393 : * making it usable in integer math.
394 : *
395 : * So we get:
396 : *
397 : * [V FIELD RATE EST] = 1000000000 / [H PERIOD EST] / [TOTAL V LINES]
398 : *
399 : * This is all scaled to get the result in uHz. Again, we're trying to
400 : * minimize error propogation.
401 : */
402 0 : v_field_est = DIVIDE(DIVIDE(1000000000000000ULL, h_period_est),
403 : total_v_lines);
404 :
405 : print_value(11, "[V FIELD RATE EST(uHz)]", v_field_est);
406 :
407 :
408 : /* 12. Find the actual horizontal period:
409 : *
410 : * [H PERIOD] = [H PERIOD EST] / ([V FIELD RATE RQD] / [V FIELD RATE EST])
411 : */
412 :
413 0 : h_period = DIVIDE(h_period_est * v_field_est, v_field_rqd * 1000);
414 :
415 : print_value(12, "[H PERIOD(ps)]", h_period);
416 :
417 :
418 : /* 13. Find the actual Vertical field frequency:
419 : *
420 : * [V FIELD RATE] = 1 / [H PERIOD] / [TOTAL V LINES] * 1000000
421 : *
422 : * And again, we convert to nsec ahead of time, giving us:
423 : *
424 : * [V FIELD RATE] = 1000000 / [H PERIOD] / [TOTAL V LINES]
425 : *
426 : * And another rescaling back to mHz. Gotta love it.
427 : */
428 :
429 0 : v_field_rate = DIVIDE(1000000000000ULL, h_period * total_v_lines);
430 :
431 : print_value(13, "[V FIELD RATE]", v_field_rate);
432 :
433 :
434 : /* 14. Find the Vertical frame frequency:
435 : *
436 : * [V FRAME RATE] = (IF([INT RQD?]="y", [V FIELD RATE]/2, [V FIELD RATE]))
437 : *
438 : * N.B. that the result here is in mHz.
439 : */
440 :
441 : v_frame_rate = (flags & VESAGTF_FLAG_ILACE) ?
442 0 : v_field_rate / 2 : v_field_rate;
443 :
444 : print_value(14, "[V FRAME RATE]", v_frame_rate);
445 :
446 :
447 : /* 15. Find number of pixels in left margin:
448 : * 16. Find number of pixels in right 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 : * Again, we deal with margin percentages as PPT (parts per thousand).
456 : * And the calculations for left and right are the same.
457 : */
458 :
459 0 : left_margin = right_margin = (flags & VESAGTF_FLAG_MARGINS) ?
460 0 : DIVIDE(DIVIDE(h_pixels * params->margin_ppt, 1000),
461 0 : CELL_GRAN) * CELL_GRAN : 0;
462 :
463 : print_value(15, "[LEFT MARGIN (PIXELS)]", left_margin);
464 : print_value(16, "[RIGHT MARGIN (PIXELS)]", right_margin);
465 :
466 :
467 : /* 17. Find total number of active pixels in image and left and right
468 : * margins:
469 : *
470 : * [TOTAL ACTIVE PIXELS] = [H PIXELS RND] + [LEFT MARGIN (PIXELS)] +
471 : * [RIGHT MARGIN (PIXELS)]
472 : */
473 :
474 0 : total_active_pixels = h_pixels + left_margin + right_margin;
475 :
476 : print_value(17, "[TOTAL ACTIVE PIXELS]", total_active_pixels);
477 :
478 :
479 : /* 18. Find the ideal blanking duty cycle from the blanking duty cycle
480 : * equation:
481 : *
482 : * [IDEAL DUTY CYCLE] = [C'] - ([M']*[H PERIOD]/1000)
483 : *
484 : * However, we have modified values for [C'] as [256*C'] and
485 : * [M'] as [256*M']. Again the idea here is to get good scaling.
486 : * We use 256 as the factor to make the math fast.
487 : *
488 : * Note that this means that we have to scale it appropriately in
489 : * later calculations.
490 : *
491 : * The ending result is that our ideal_duty_cycle is 256000x larger
492 : * than the duty cycle used by VESA. But again, this reduces error
493 : * propogation.
494 : */
495 :
496 : ideal_duty_cycle =
497 0 : ((C_PRIME256(params) * 1000) -
498 0 : (M_PRIME256(params) * h_period / 1000000));
499 :
500 : print_value(18, "[IDEAL DUTY CYCLE]", ideal_duty_cycle);
501 :
502 :
503 : /* 19. Find the number of pixels in the blanking time to the nearest
504 : * double character cell:
505 : *
506 : * [H BLANK (PIXELS)] = (ROUND(([TOTAL ACTIVE PIXELS] *
507 : * [IDEAL DUTY CYCLE] /
508 : * (100-[IDEAL DUTY CYCLE]) /
509 : * (2*[CELL GRAN RND])), 0))
510 : * * (2*[CELL GRAN RND])
511 : *
512 : * Of course, we adjust to make this rounding work in integer math.
513 : */
514 :
515 0 : h_blank = DIVIDE(DIVIDE(total_active_pixels * ideal_duty_cycle,
516 : (256000 * 100ULL) - ideal_duty_cycle),
517 0 : 2 * CELL_GRAN) * (2 * CELL_GRAN);
518 :
519 : print_value(19, "[H BLANK (PIXELS)]", h_blank);
520 :
521 :
522 : /* 20. Find total number of pixels:
523 : *
524 : * [TOTAL PIXELS] = [TOTAL ACTIVE PIXELS] + [H BLANK (PIXELS)]
525 : */
526 :
527 0 : total_pixels = total_active_pixels + h_blank;
528 :
529 : print_value(20, "[TOTAL PIXELS]", total_pixels);
530 :
531 :
532 : /* 21. Find pixel clock frequency:
533 : *
534 : * [PIXEL FREQ] = [TOTAL PIXELS] / [H PERIOD]
535 : *
536 : * We calculate this in Hz rather than MHz, to get a value that
537 : * is usable with integer math. Recall that the [H PERIOD] is in
538 : * nsec.
539 : */
540 :
541 0 : pixel_freq = DIVIDE(total_pixels * 1000000, DIVIDE(h_period, 1000));
542 :
543 : print_value(21, "[PIXEL FREQ]", pixel_freq);
544 :
545 :
546 : /* 22. Find horizontal frequency:
547 : *
548 : * [H FREQ] = 1000 / [H PERIOD]
549 : *
550 : * I've ifdef'd this out, because we don't need it for any of
551 : * our calculations.
552 : * We calculate this in Hz rather than kHz, to avoid rounding
553 : * errors. Recall that the [H PERIOD] is in usec.
554 : */
555 :
556 : #ifdef GTFDEBUG
557 : h_freq = 1000000000 / h_period;
558 :
559 : print_value(22, "[H FREQ]", h_freq);
560 : #endif
561 :
562 :
563 :
564 : /* Stage 1 computations are now complete; I should really pass
565 : the results to another function and do the Stage 2
566 : computations, but I only need a few more values so I'll just
567 : append the computations here for now */
568 :
569 :
570 :
571 : /* 17. Find the number of pixels in the horizontal sync period:
572 : *
573 : * [H SYNC (PIXELS)] =(ROUND(([H SYNC%] / 100 * [TOTAL PIXELS] /
574 : * [CELL GRAN RND]),0))*[CELL GRAN RND]
575 : *
576 : * Rewriting for integer math:
577 : *
578 : * [H SYNC (PIXELS)]=(ROUND((H SYNC%] * [TOTAL PIXELS] / 100 /
579 : * [CELL GRAN RND),0))*[CELL GRAN RND]
580 : */
581 :
582 0 : h_sync = DIVIDE(((params->hsync_pct * total_pixels) / 100), CELL_GRAN) *
583 : CELL_GRAN;
584 :
585 : print_value(17, "[H SYNC (PIXELS)]", h_sync);
586 :
587 :
588 : /* 18. Find the number of pixels in the horizontal front porch period:
589 : *
590 : * [H FRONT PORCH (PIXELS)] = ([H BLANK (PIXELS)]/2)-[H SYNC (PIXELS)]
591 : *
592 : * Note that h_blank is always an even number of characters (i.e.
593 : * h_blank % (CELL_GRAN * 2) == 0)
594 : */
595 :
596 0 : h_front_porch = (h_blank / 2) - h_sync;
597 :
598 : print_value(18, "[H FRONT PORCH (PIXELS)]", h_front_porch);
599 :
600 :
601 : /* 36. Find the number of lines in the odd front porch period:
602 : *
603 : * [V ODD FRONT PORCH(LINES)]=([MIN PORCH RND]+[INTERLACE])
604 : *
605 : * Adjusting for the fact that the interlace is scaled:
606 : *
607 : * [V ODD FRONT PORCH(LINES)]=(([MIN PORCH RND] * 2) + [2*INTERLACE]) / 2
608 : */
609 :
610 0 : v_odd_front_porch_lines = ((2 * params->min_porch) + interlace) / 2;
611 :
612 : print_value(36, "[V ODD FRONT PORCH(LINES)]", v_odd_front_porch_lines);
613 :
614 :
615 : /* finally, pack the results in the mode struct */
616 :
617 0 : vmp->hsync_start = h_pixels + h_front_porch;
618 0 : vmp->hsync_end = vmp->hsync_start + h_sync;
619 0 : vmp->htotal = total_pixels;
620 0 : vmp->hdisplay = h_pixels;
621 :
622 0 : vmp->vsync_start = v_lines + v_odd_front_porch_lines;
623 0 : vmp->vsync_end = vmp->vsync_start + params->vsync_rqd;
624 0 : vmp->vtotal = total_v_lines;
625 0 : vmp->vdisplay = v_lines;
626 :
627 0 : vmp->dot_clock = pixel_freq;
628 :
629 0 : }
630 :
631 : void
632 0 : vesagtf_mode(unsigned x, unsigned y, unsigned refresh, struct videomode *vmp)
633 : {
634 0 : struct vesagtf_params params;
635 :
636 0 : params.margin_ppt = VESAGTF_MARGIN_PPT;
637 0 : params.min_porch = VESAGTF_MIN_PORCH;
638 0 : params.vsync_rqd = VESAGTF_VSYNC_RQD;
639 0 : params.hsync_pct = VESAGTF_HSYNC_PCT;
640 0 : params.min_vsbp = VESAGTF_MIN_VSBP;
641 0 : params.M = VESAGTF_M;
642 0 : params.C = VESAGTF_C;
643 0 : params.K = VESAGTF_K;
644 0 : params.J = VESAGTF_J;
645 :
646 0 : vesagtf_mode_params(x, y, refresh, ¶ms, 0, vmp);
647 0 : }
648 :
649 : /*
650 : * The tidbit here is so that you can compile this file as a
651 : * standalone user program to generate X11 modelines using VESA GTF.
652 : * This also allows for testing of the code itself, without
653 : * necessitating a full kernel recompile.
654 : */
655 :
656 : /* print_xf86_mode() - print the XFree86 modeline, given mode timings. */
657 :
658 : #ifndef _KERNEL
659 : void
660 : print_xf86_mode (struct videomode *vmp)
661 : {
662 : float vf, hf;
663 :
664 : hf = 1000.0 * vmp->dot_clock / vmp->htotal;
665 : vf = 1.0 * hf / vmp->vtotal;
666 :
667 : printf("\n");
668 : printf(" # %dx%d @ %.2f Hz (GTF) hsync: %.2f kHz; pclk: %.2f MHz\n",
669 : vmp->hdisplay, vmp->vdisplay, vf, hf, vmp->dot_clock / 1000.0);
670 :
671 : printf(" Modeline \"%dx%d_%.2f\" %.2f"
672 : " %d %d %d %d"
673 : " %d %d %d %d"
674 : " -HSync +Vsync\n\n",
675 : vmp->hdisplay, vmp->vdisplay, vf, (vmp->dot_clock / 1000.0),
676 : vmp->hdisplay, vmp->hsync_start, vmp->hsync_end, vmp->htotal,
677 : vmp->vdisplay, vmp->vsync_start, vmp->vsync_end, vmp->vtotal);
678 : }
679 :
680 : int
681 : main (int argc, char *argv[])
682 : {
683 : struct videomode m;
684 :
685 : if (argc != 4) {
686 : printf("usage: %s x y refresh\n", argv[0]);
687 : exit(1);
688 : }
689 :
690 : vesagtf_mode(atoi(argv[1]), atoi(argv[2]), atoi(argv[3]), &m);
691 :
692 : print_xf86_mode(&m);
693 :
694 : return 0;
695 :
696 : }
697 : #endif
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