1 | /* $NetBSD: vesagtf.c,v 1.3 2014/03/21 22:00:00 dholland 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 propagation 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/cdefs.h> |
155 | |
156 | __KERNEL_RCSID(0, "$NetBSD: vesagtf.c,v 1.3 2014/03/21 22:00:00 dholland Exp $" ); |
157 | #include <sys/types.h> |
158 | #include <sys/param.h> |
159 | #include <sys/systm.h> |
160 | #include <dev/videomode/videomode.h> |
161 | #include <dev/videomode/vesagtf.h> |
162 | #else |
163 | #include <stdio.h> |
164 | #include <stdlib.h> |
165 | #include <sys/types.h> |
166 | #include "videomode.h" |
167 | #include "vesagtf.h" |
168 | |
169 | void print_xf86_mode(struct videomode *m); |
170 | #endif |
171 | |
172 | #define CELL_GRAN 8 /* assumed character cell granularity */ |
173 | |
174 | /* C' and M' are part of the Blanking Duty Cycle computation */ |
175 | /* |
176 | * #define C_PRIME (((C - J) * K/256.0) + J) |
177 | * #define M_PRIME (K/256.0 * M) |
178 | */ |
179 | |
180 | /* |
181 | * C' and M' multiplied by 256 to give integer math. Make sure to |
182 | * scale results using these back down, appropriately. |
183 | */ |
184 | #define C_PRIME256(p) (((p->C - p->J) * p->K) + (p->J * 256)) |
185 | #define M_PRIME256(p) (p->K * p->M) |
186 | |
187 | #define DIVIDE(x,y) (((x) + ((y) / 2)) / (y)) |
188 | |
189 | /* |
190 | * print_value() - print the result of the named computation; this is |
191 | * useful when comparing against the GTF EXCEL spreadsheet. |
192 | */ |
193 | |
194 | #ifdef GTFDEBUG |
195 | |
196 | static void |
197 | print_value(int n, const char *name, unsigned val) |
198 | { |
199 | printf("%2d: %-27s: %u\n" , n, name, val); |
200 | } |
201 | #else |
202 | #define print_value(n, name, val) |
203 | #endif |
204 | |
205 | |
206 | /* |
207 | * vert_refresh() - as defined by the GTF Timing Standard, compute the |
208 | * Stage 1 Parameters using the vertical refresh frequency. In other |
209 | * words: input a desired resolution and desired refresh rate, and |
210 | * output the GTF mode timings. |
211 | * |
212 | * XXX All the code is in place to compute interlaced modes, but I don't |
213 | * feel like testing it right now. |
214 | * |
215 | * XXX margin computations are implemented but not tested (nor used by |
216 | * XFree86 of fbset mode descriptions, from what I can tell). |
217 | */ |
218 | |
219 | void |
220 | vesagtf_mode_params(unsigned h_pixels, unsigned v_lines, unsigned freq, |
221 | struct vesagtf_params *params, int flags, struct videomode *vmp) |
222 | { |
223 | unsigned v_field_rqd; |
224 | unsigned top_margin; |
225 | unsigned bottom_margin; |
226 | unsigned interlace; |
227 | uint64_t h_period_est; |
228 | unsigned vsync_plus_bp; |
229 | unsigned v_back_porch __unused; |
230 | unsigned total_v_lines; |
231 | uint64_t v_field_est; |
232 | uint64_t h_period; |
233 | unsigned v_field_rate; |
234 | unsigned v_frame_rate __unused; |
235 | unsigned left_margin; |
236 | unsigned right_margin; |
237 | unsigned total_active_pixels; |
238 | uint64_t ideal_duty_cycle; |
239 | unsigned h_blank; |
240 | unsigned total_pixels; |
241 | unsigned pixel_freq; |
242 | |
243 | unsigned h_sync; |
244 | unsigned h_front_porch; |
245 | unsigned v_odd_front_porch_lines; |
246 | |
247 | #ifdef GTFDEBUG |
248 | unsigned h_freq; |
249 | #endif |
250 | |
251 | /* 1. In order to give correct results, the number of horizontal |
252 | * pixels requested is first processed to ensure that it is divisible |
253 | * by the character size, by rounding it to the nearest character |
254 | * cell boundary: |
255 | * |
256 | * [H PIXELS RND] = ((ROUND([H PIXELS]/[CELL GRAN RND],0))*[CELLGRAN RND]) |
257 | */ |
258 | |
259 | h_pixels = DIVIDE(h_pixels, CELL_GRAN) * CELL_GRAN; |
260 | |
261 | print_value(1, "[H PIXELS RND]" , h_pixels); |
262 | |
263 | |
264 | /* 2. If interlace is requested, the number of vertical lines assumed |
265 | * by the calculation must be halved, as the computation calculates |
266 | * the number of vertical lines per field. In either case, the |
267 | * number of lines is rounded to the nearest integer. |
268 | * |
269 | * [V LINES RND] = IF([INT RQD?]="y", ROUND([V LINES]/2,0), |
270 | * ROUND([V LINES],0)) |
271 | */ |
272 | |
273 | v_lines = (flags & VESAGTF_FLAG_ILACE) ? DIVIDE(v_lines, 2) : v_lines; |
274 | |
275 | print_value(2, "[V LINES RND]" , v_lines); |
276 | |
277 | |
278 | /* 3. Find the frame rate required: |
279 | * |
280 | * [V FIELD RATE RQD] = IF([INT RQD?]="y", [I/P FREQ RQD]*2, |
281 | * [I/P FREQ RQD]) |
282 | */ |
283 | |
284 | v_field_rqd = (flags & VESAGTF_FLAG_ILACE) ? (freq * 2) : (freq); |
285 | |
286 | print_value(3, "[V FIELD RATE RQD]" , v_field_rqd); |
287 | |
288 | |
289 | /* 4. Find number of lines in Top margin: |
290 | * 5. Find number of lines in Bottom margin: |
291 | * |
292 | * [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y", |
293 | * ROUND(([MARGIN%]/100*[V LINES RND]),0), |
294 | * 0) |
295 | * |
296 | * Ditto for bottom margin. Note that instead of %, we use PPT, which |
297 | * is parts per thousand. This helps us with integer math. |
298 | */ |
299 | |
300 | top_margin = bottom_margin = (flags & VESAGTF_FLAG_MARGINS) ? |
301 | DIVIDE(v_lines * params->margin_ppt, 1000) : 0; |
302 | |
303 | print_value(4, "[TOP MARGIN (LINES)]" , top_margin); |
304 | print_value(5, "[BOT MARGIN (LINES)]" , bottom_margin); |
305 | |
306 | |
307 | /* 6. If interlace is required, then set variable [INTERLACE]=0.5: |
308 | * |
309 | * [INTERLACE]=(IF([INT RQD?]="y",0.5,0)) |
310 | * |
311 | * To make this integer friendly, we use some special hacks in step |
312 | * 7 below. Please read those comments to understand why I am using |
313 | * a whole number of 1.0 instead of 0.5 here. |
314 | */ |
315 | interlace = (flags & VESAGTF_FLAG_ILACE) ? 1 : 0; |
316 | |
317 | print_value(6, "[2*INTERLACE]" , interlace); |
318 | |
319 | |
320 | /* 7. Estimate the Horizontal period |
321 | * |
322 | * [H PERIOD EST] = ((1/[V FIELD RATE RQD]) - [MIN VSYNC+BP]/1000000) / |
323 | * ([V LINES RND] + (2*[TOP MARGIN (LINES)]) + |
324 | * [MIN PORCH RND]+[INTERLACE]) * 1000000 |
325 | * |
326 | * To make it integer friendly, we pre-multiply the 1000000 to get to |
327 | * usec. This gives us: |
328 | * |
329 | * [H PERIOD EST] = ((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP]) / |
330 | * ([V LINES RND] + (2 * [TOP MARGIN (LINES)]) + |
331 | * [MIN PORCH RND]+[INTERLACE]) |
332 | * |
333 | * The other problem is that the interlace value is wrong. To get |
334 | * the interlace to a whole number, we multiply both the numerator and |
335 | * divisor by 2, so we can use a value of either 1 or 0 for the interlace |
336 | * factor. |
337 | * |
338 | * This gives us: |
339 | * |
340 | * [H PERIOD EST] = ((2*((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP])) / |
341 | * (2*([V LINES RND] + (2*[TOP MARGIN (LINES)]) + |
342 | * [MIN PORCH RND]) + [2*INTERLACE])) |
343 | * |
344 | * Finally we multiply by another 1000, to get value in picosec. |
345 | * Why picosec? To minimize rounding errors. Gotta love integer |
346 | * math and error propagation. |
347 | */ |
348 | |
349 | h_period_est = DIVIDE(((DIVIDE(2000000000000ULL, v_field_rqd)) - |
350 | (2000000 * params->min_vsbp)), |
351 | ((2 * (v_lines + (2 * top_margin) + params->min_porch)) + interlace)); |
352 | |
353 | print_value(7, "[H PERIOD EST (ps)]" , h_period_est); |
354 | |
355 | |
356 | /* 8. Find the number of lines in V sync + back porch: |
357 | * |
358 | * [V SYNC+BP] = ROUND(([MIN VSYNC+BP]/[H PERIOD EST]),0) |
359 | * |
360 | * But recall that h_period_est is in psec. So multiply by 1000000. |
361 | */ |
362 | |
363 | vsync_plus_bp = DIVIDE(params->min_vsbp * 1000000, h_period_est); |
364 | |
365 | print_value(8, "[V SYNC+BP]" , vsync_plus_bp); |
366 | |
367 | |
368 | /* 9. Find the number of lines in V back porch alone: |
369 | * |
370 | * [V BACK PORCH] = [V SYNC+BP] - [V SYNC RND] |
371 | * |
372 | * XXX is "[V SYNC RND]" a typo? should be [V SYNC RQD]? |
373 | */ |
374 | |
375 | v_back_porch = vsync_plus_bp - params->vsync_rqd; |
376 | |
377 | print_value(9, "[V BACK PORCH]" , v_back_porch); |
378 | |
379 | |
380 | /* 10. Find the total number of lines in Vertical field period: |
381 | * |
382 | * [TOTAL V LINES] = [V LINES RND] + [TOP MARGIN (LINES)] + |
383 | * [BOT MARGIN (LINES)] + [V SYNC+BP] + [INTERLACE] + |
384 | * [MIN PORCH RND] |
385 | */ |
386 | |
387 | total_v_lines = v_lines + top_margin + bottom_margin + vsync_plus_bp + |
388 | interlace + params->min_porch; |
389 | |
390 | print_value(10, "[TOTAL V LINES]" , total_v_lines); |
391 | |
392 | |
393 | /* 11. Estimate the Vertical field frequency: |
394 | * |
395 | * [V FIELD RATE EST] = 1 / [H PERIOD EST] / [TOTAL V LINES] * 1000000 |
396 | * |
397 | * Again, we want to pre multiply by 10^9 to convert for nsec, thereby |
398 | * making it usable in integer math. |
399 | * |
400 | * So we get: |
401 | * |
402 | * [V FIELD RATE EST] = 1000000000 / [H PERIOD EST] / [TOTAL V LINES] |
403 | * |
404 | * This is all scaled to get the result in uHz. Again, we're trying to |
405 | * minimize error propagation. |
406 | */ |
407 | v_field_est = DIVIDE(DIVIDE(1000000000000000ULL, h_period_est), |
408 | total_v_lines); |
409 | |
410 | print_value(11, "[V FIELD RATE EST(uHz)]" , v_field_est); |
411 | |
412 | |
413 | /* 12. Find the actual horizontal period: |
414 | * |
415 | * [H PERIOD] = [H PERIOD EST] / ([V FIELD RATE RQD] / [V FIELD RATE EST]) |
416 | */ |
417 | |
418 | h_period = DIVIDE(h_period_est * v_field_est, v_field_rqd * 1000); |
419 | |
420 | print_value(12, "[H PERIOD(ps)]" , h_period); |
421 | |
422 | |
423 | /* 13. Find the actual Vertical field frequency: |
424 | * |
425 | * [V FIELD RATE] = 1 / [H PERIOD] / [TOTAL V LINES] * 1000000 |
426 | * |
427 | * And again, we convert to nsec ahead of time, giving us: |
428 | * |
429 | * [V FIELD RATE] = 1000000 / [H PERIOD] / [TOTAL V LINES] |
430 | * |
431 | * And another rescaling back to mHz. Gotta love it. |
432 | */ |
433 | |
434 | v_field_rate = DIVIDE(1000000000000ULL, h_period * total_v_lines); |
435 | |
436 | print_value(13, "[V FIELD RATE]" , v_field_rate); |
437 | |
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 | * N.B. that the result here is in mHz. |
444 | */ |
445 | |
446 | v_frame_rate = (flags & VESAGTF_FLAG_ILACE) ? |
447 | v_field_rate / 2 : v_field_rate; |
448 | |
449 | print_value(14, "[V FRAME RATE]" , v_frame_rate); |
450 | |
451 | |
452 | /* 15. Find number of pixels in left margin: |
453 | * 16. Find number of pixels in right margin: |
454 | * |
455 | * [LEFT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y", |
456 | * (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 / |
457 | * [CELL GRAN RND]),0)) * [CELL GRAN RND], |
458 | * 0)) |
459 | * |
460 | * Again, we deal with margin percentages as PPT (parts per thousand). |
461 | * And the calculations for left and right are the same. |
462 | */ |
463 | |
464 | left_margin = right_margin = (flags & VESAGTF_FLAG_MARGINS) ? |
465 | DIVIDE(DIVIDE(h_pixels * params->margin_ppt, 1000), |
466 | CELL_GRAN) * CELL_GRAN : 0; |
467 | |
468 | print_value(15, "[LEFT MARGIN (PIXELS)]" , left_margin); |
469 | print_value(16, "[RIGHT MARGIN (PIXELS)]" , right_margin); |
470 | |
471 | |
472 | /* 17. Find total number of active pixels in image and left and right |
473 | * margins: |
474 | * |
475 | * [TOTAL ACTIVE PIXELS] = [H PIXELS RND] + [LEFT MARGIN (PIXELS)] + |
476 | * [RIGHT MARGIN (PIXELS)] |
477 | */ |
478 | |
479 | total_active_pixels = h_pixels + left_margin + right_margin; |
480 | |
481 | print_value(17, "[TOTAL ACTIVE PIXELS]" , total_active_pixels); |
482 | |
483 | |
484 | /* 18. Find the ideal blanking duty cycle from the blanking duty cycle |
485 | * equation: |
486 | * |
487 | * [IDEAL DUTY CYCLE] = [C'] - ([M']*[H PERIOD]/1000) |
488 | * |
489 | * However, we have modified values for [C'] as [256*C'] and |
490 | * [M'] as [256*M']. Again the idea here is to get good scaling. |
491 | * We use 256 as the factor to make the math fast. |
492 | * |
493 | * Note that this means that we have to scale it appropriately in |
494 | * later calculations. |
495 | * |
496 | * The ending result is that our ideal_duty_cycle is 256000x larger |
497 | * than the duty cycle used by VESA. But again, this reduces error |
498 | * propagation. |
499 | */ |
500 | |
501 | ideal_duty_cycle = |
502 | ((C_PRIME256(params) * 1000) - |
503 | (M_PRIME256(params) * h_period / 1000000)); |
504 | |
505 | print_value(18, "[IDEAL DUTY CYCLE]" , ideal_duty_cycle); |
506 | |
507 | |
508 | /* 19. Find the number of pixels in the blanking time to the nearest |
509 | * double character cell: |
510 | * |
511 | * [H BLANK (PIXELS)] = (ROUND(([TOTAL ACTIVE PIXELS] * |
512 | * [IDEAL DUTY CYCLE] / |
513 | * (100-[IDEAL DUTY CYCLE]) / |
514 | * (2*[CELL GRAN RND])), 0)) |
515 | * * (2*[CELL GRAN RND]) |
516 | * |
517 | * Of course, we adjust to make this rounding work in integer math. |
518 | */ |
519 | |
520 | h_blank = DIVIDE(DIVIDE(total_active_pixels * ideal_duty_cycle, |
521 | (256000 * 100ULL) - ideal_duty_cycle), |
522 | 2 * CELL_GRAN) * (2 * CELL_GRAN); |
523 | |
524 | print_value(19, "[H BLANK (PIXELS)]" , h_blank); |
525 | |
526 | |
527 | /* 20. Find total number of pixels: |
528 | * |
529 | * [TOTAL PIXELS] = [TOTAL ACTIVE PIXELS] + [H BLANK (PIXELS)] |
530 | */ |
531 | |
532 | total_pixels = total_active_pixels + h_blank; |
533 | |
534 | print_value(20, "[TOTAL PIXELS]" , total_pixels); |
535 | |
536 | |
537 | /* 21. Find pixel clock frequency: |
538 | * |
539 | * [PIXEL FREQ] = [TOTAL PIXELS] / [H PERIOD] |
540 | * |
541 | * We calculate this in Hz rather than MHz, to get a value that |
542 | * is usable with integer math. Recall that the [H PERIOD] is in |
543 | * nsec. |
544 | */ |
545 | |
546 | pixel_freq = DIVIDE(total_pixels * 1000000, DIVIDE(h_period, 1000)); |
547 | |
548 | print_value(21, "[PIXEL FREQ]" , pixel_freq); |
549 | |
550 | |
551 | /* 22. Find horizontal frequency: |
552 | * |
553 | * [H FREQ] = 1000 / [H PERIOD] |
554 | * |
555 | * I've ifdef'd this out, because we don't need it for any of |
556 | * our calculations. |
557 | * We calculate this in Hz rather than kHz, to avoid rounding |
558 | * errors. Recall that the [H PERIOD] is in usec. |
559 | */ |
560 | |
561 | #ifdef GTFDEBUG |
562 | h_freq = 1000000000 / h_period; |
563 | |
564 | print_value(22, "[H FREQ]" , h_freq); |
565 | #endif |
566 | |
567 | |
568 | |
569 | /* Stage 1 computations are now complete; I should really pass |
570 | the results to another function and do the Stage 2 |
571 | computations, but I only need a few more values so I'll just |
572 | append the computations here for now */ |
573 | |
574 | |
575 | |
576 | /* 17. Find the number of pixels in the horizontal sync period: |
577 | * |
578 | * [H SYNC (PIXELS)] =(ROUND(([H SYNC%] / 100 * [TOTAL PIXELS] / |
579 | * [CELL GRAN RND]),0))*[CELL GRAN RND] |
580 | * |
581 | * Rewriting for integer math: |
582 | * |
583 | * [H SYNC (PIXELS)]=(ROUND((H SYNC%] * [TOTAL PIXELS] / 100 / |
584 | * [CELL GRAN RND),0))*[CELL GRAN RND] |
585 | */ |
586 | |
587 | h_sync = DIVIDE(((params->hsync_pct * total_pixels) / 100), CELL_GRAN) * |
588 | CELL_GRAN; |
589 | |
590 | print_value(17, "[H SYNC (PIXELS)]" , h_sync); |
591 | |
592 | |
593 | /* 18. Find the number of pixels in the horizontal front porch period: |
594 | * |
595 | * [H FRONT PORCH (PIXELS)] = ([H BLANK (PIXELS)]/2)-[H SYNC (PIXELS)] |
596 | * |
597 | * Note that h_blank is always an even number of characters (i.e. |
598 | * h_blank % (CELL_GRAN * 2) == 0) |
599 | */ |
600 | |
601 | h_front_porch = (h_blank / 2) - h_sync; |
602 | |
603 | print_value(18, "[H FRONT PORCH (PIXELS)]" , h_front_porch); |
604 | |
605 | |
606 | /* 36. Find the number of lines in the odd front porch period: |
607 | * |
608 | * [V ODD FRONT PORCH(LINES)]=([MIN PORCH RND]+[INTERLACE]) |
609 | * |
610 | * Adjusting for the fact that the interlace is scaled: |
611 | * |
612 | * [V ODD FRONT PORCH(LINES)]=(([MIN PORCH RND] * 2) + [2*INTERLACE]) / 2 |
613 | */ |
614 | |
615 | v_odd_front_porch_lines = ((2 * params->min_porch) + interlace) / 2; |
616 | |
617 | print_value(36, "[V ODD FRONT PORCH(LINES)]" , v_odd_front_porch_lines); |
618 | |
619 | |
620 | /* finally, pack the results in the mode struct */ |
621 | |
622 | vmp->hsync_start = h_pixels + h_front_porch; |
623 | vmp->hsync_end = vmp->hsync_start + h_sync; |
624 | vmp->htotal = total_pixels; |
625 | vmp->hdisplay = h_pixels; |
626 | |
627 | vmp->vsync_start = v_lines + v_odd_front_porch_lines; |
628 | vmp->vsync_end = vmp->vsync_start + params->vsync_rqd; |
629 | vmp->vtotal = total_v_lines; |
630 | vmp->vdisplay = v_lines; |
631 | |
632 | vmp->dot_clock = pixel_freq; |
633 | |
634 | } |
635 | |
636 | void |
637 | vesagtf_mode(unsigned x, unsigned y, unsigned refresh, struct videomode *vmp) |
638 | { |
639 | struct vesagtf_params params; |
640 | |
641 | params.margin_ppt = VESAGTF_MARGIN_PPT; |
642 | params.min_porch = VESAGTF_MIN_PORCH; |
643 | params.vsync_rqd = VESAGTF_VSYNC_RQD; |
644 | params.hsync_pct = VESAGTF_HSYNC_PCT; |
645 | params.min_vsbp = VESAGTF_MIN_VSBP; |
646 | params.M = VESAGTF_M; |
647 | params.C = VESAGTF_C; |
648 | params.K = VESAGTF_K; |
649 | params.J = VESAGTF_J; |
650 | |
651 | vesagtf_mode_params(x, y, refresh, ¶ms, 0, vmp); |
652 | } |
653 | |
654 | /* |
655 | * The tidbit here is so that you can compile this file as a |
656 | * standalone user program to generate X11 modelines using VESA GTF. |
657 | * This also allows for testing of the code itself, without |
658 | * necessitating a full kernel recompile. |
659 | */ |
660 | |
661 | /* print_xf86_mode() - print the XFree86 modeline, given mode timings. */ |
662 | |
663 | #ifndef _KERNEL |
664 | void |
665 | print_xf86_mode (struct videomode *vmp) |
666 | { |
667 | float vf, hf; |
668 | |
669 | hf = 1000.0 * vmp->dot_clock / vmp->htotal; |
670 | vf = 1.0 * hf / vmp->vtotal; |
671 | |
672 | printf("\n" ); |
673 | printf(" # %dx%d @ %.2f Hz (GTF) hsync: %.2f kHz; pclk: %.2f MHz\n" , |
674 | vmp->hdisplay, vmp->vdisplay, vf, hf, vmp->dot_clock / 1000.0); |
675 | |
676 | printf(" Modeline \"%dx%d_%.2f\" %.2f" |
677 | " %d %d %d %d" |
678 | " %d %d %d %d" |
679 | " -HSync +Vsync\n\n" , |
680 | vmp->hdisplay, vmp->vdisplay, vf, (vmp->dot_clock / 1000.0), |
681 | vmp->hdisplay, vmp->hsync_start, vmp->hsync_end, vmp->htotal, |
682 | vmp->vdisplay, vmp->vsync_start, vmp->vsync_end, vmp->vtotal); |
683 | } |
684 | |
685 | int |
686 | main (int argc, char *argv[]) |
687 | { |
688 | struct videomode m; |
689 | |
690 | if (argc != 4) { |
691 | printf("usage: %s x y refresh\n" , argv[0]); |
692 | exit(1); |
693 | } |
694 | |
695 | vesagtf_mode(atoi(argv[1]), atoi(argv[2]), atoi(argv[3]), &m); |
696 | |
697 | print_xf86_mode(&m); |
698 | |
699 | return 0; |
700 | |
701 | } |
702 | #endif |
703 | |