File: | dev/videomode/vesagtf.c |
Warning: | line 441, column 5 Value stored to 'v_frame_rate' is never read |
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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 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 _KERNEL1 |
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_GRAN8 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)) (((p->C - p->J) * p->K) + (p->J * 256)) |
180 | #define M_PRIME256(p)(p->K * p->M) (p->K * p->M) |
181 | |
182 | #define DIVIDE(x,y)(((x) + ((y) / 2)) / (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 | 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 | h_pixels = DIVIDE(h_pixels, CELL_GRAN)(((h_pixels) + ((8) / 2)) / (8)) * CELL_GRAN8; |
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 | v_lines = (flags & VESAGTF_FLAG_ILACE0x0001) ? DIVIDE(v_lines, 2)(((v_lines) + ((2) / 2)) / (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 | v_field_rqd = (flags & VESAGTF_FLAG_ILACE0x0001) ? (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 | top_margin = bottom_margin = (flags & VESAGTF_FLAG_MARGINS0x0002) ? |
296 | DIVIDE(v_lines * params->margin_ppt, 1000)(((v_lines * params->margin_ppt) + ((1000) / 2)) / (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 | interlace = (flags & VESAGTF_FLAG_ILACE0x0001) ? 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 propagation. |
342 | */ |
343 | |
344 | h_period_est = DIVIDE(((DIVIDE(2000000000000ULL, v_field_rqd)) -((((((((2000000000000ULL) + ((v_field_rqd) / 2)) / (v_field_rqd ))) - (2000000 * params->min_vsbp))) + ((((2 * (v_lines + ( 2 * top_margin) + params->min_porch)) + interlace)) / 2)) / (((2 * (v_lines + (2 * top_margin) + params->min_porch)) + interlace))) |
345 | (2000000 * params->min_vsbp)),((((((((2000000000000ULL) + ((v_field_rqd) / 2)) / (v_field_rqd ))) - (2000000 * params->min_vsbp))) + ((((2 * (v_lines + ( 2 * top_margin) + params->min_porch)) + interlace)) / 2)) / (((2 * (v_lines + (2 * top_margin) + params->min_porch)) + interlace))) |
346 | ((2 * (v_lines + (2 * top_margin) + params->min_porch)) + interlace))((((((((2000000000000ULL) + ((v_field_rqd) / 2)) / (v_field_rqd ))) - (2000000 * params->min_vsbp))) + ((((2 * (v_lines + ( 2 * top_margin) + params->min_porch)) + interlace)) / 2)) / (((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 | vsync_plus_bp = DIVIDE(params->min_vsbp * 1000000, h_period_est)(((params->min_vsbp * 1000000) + ((h_period_est) / 2)) / ( 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 | 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 | total_v_lines = v_lines + top_margin + bottom_margin + vsync_plus_bp + |
383 | 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 propagation. |
401 | */ |
402 | v_field_est = DIVIDE(DIVIDE(1000000000000000ULL, h_period_est),((((((1000000000000000ULL) + ((h_period_est) / 2)) / (h_period_est ))) + ((total_v_lines) / 2)) / (total_v_lines)) |
403 | total_v_lines)((((((1000000000000000ULL) + ((h_period_est) / 2)) / (h_period_est ))) + ((total_v_lines) / 2)) / (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 | h_period = DIVIDE(h_period_est * v_field_est, v_field_rqd * 1000)(((h_period_est * v_field_est) + ((v_field_rqd * 1000) / 2)) / (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 | v_field_rate = DIVIDE(1000000000000ULL, h_period * total_v_lines)(((1000000000000ULL) + ((h_period * total_v_lines) / 2)) / (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_ILACE0x0001) ? |
Value stored to 'v_frame_rate' is never read | |
442 | 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 | left_margin = right_margin = (flags & VESAGTF_FLAG_MARGINS0x0002) ? |
460 | DIVIDE(DIVIDE(h_pixels * params->margin_ppt, 1000),((((((h_pixels * params->margin_ppt) + ((1000) / 2)) / (1000 ))) + ((8) / 2)) / (8)) |
461 | CELL_GRAN)((((((h_pixels * params->margin_ppt) + ((1000) / 2)) / (1000 ))) + ((8) / 2)) / (8)) * CELL_GRAN8 : 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 | 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 | * propagation. |
494 | */ |
495 | |
496 | ideal_duty_cycle = |
497 | ((C_PRIME256(params)(((params->C - params->J) * params->K) + (params-> J * 256)) * 1000) - |
498 | (M_PRIME256(params)(params->K * params->M) * 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 | h_blank = DIVIDE(DIVIDE(total_active_pixels * ideal_duty_cycle,((((((total_active_pixels * ideal_duty_cycle) + (((256000 * 100ULL ) - ideal_duty_cycle) / 2)) / ((256000 * 100ULL) - ideal_duty_cycle ))) + ((2 * 8) / 2)) / (2 * 8)) |
516 | (256000 * 100ULL) - ideal_duty_cycle),((((((total_active_pixels * ideal_duty_cycle) + (((256000 * 100ULL ) - ideal_duty_cycle) / 2)) / ((256000 * 100ULL) - ideal_duty_cycle ))) + ((2 * 8) / 2)) / (2 * 8)) |
517 | 2 * CELL_GRAN)((((((total_active_pixels * ideal_duty_cycle) + (((256000 * 100ULL ) - ideal_duty_cycle) / 2)) / ((256000 * 100ULL) - ideal_duty_cycle ))) + ((2 * 8) / 2)) / (2 * 8)) * (2 * CELL_GRAN8); |
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 | 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 | pixel_freq = DIVIDE(total_pixels * 1000000, DIVIDE(h_period, 1000))(((total_pixels * 1000000) + (((((h_period) + ((1000) / 2)) / (1000))) / 2)) / ((((h_period) + ((1000) / 2)) / (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 | h_sync = DIVIDE(((params->hsync_pct * total_pixels) / 100), CELL_GRAN)(((((params->hsync_pct * total_pixels) / 100)) + ((8) / 2) ) / (8)) * |
583 | CELL_GRAN8; |
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 | 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 | 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 | vmp->hsync_start = h_pixels + h_front_porch; |
618 | vmp->hsync_end = vmp->hsync_start + h_sync; |
619 | vmp->htotal = total_pixels; |
620 | vmp->hdisplay = h_pixels; |
621 | |
622 | vmp->vsync_start = v_lines + v_odd_front_porch_lines; |
623 | vmp->vsync_end = vmp->vsync_start + params->vsync_rqd; |
624 | vmp->vtotal = total_v_lines; |
625 | vmp->vdisplay = v_lines; |
626 | |
627 | vmp->dot_clock = pixel_freq; |
628 | |
629 | } |
630 | |
631 | void |
632 | vesagtf_mode(unsigned x, unsigned y, unsigned refresh, struct videomode *vmp) |
633 | { |
634 | struct vesagtf_params params; |
635 | |
636 | params.margin_ppt = VESAGTF_MARGIN_PPT18; |
637 | params.min_porch = VESAGTF_MIN_PORCH1; |
638 | params.vsync_rqd = VESAGTF_VSYNC_RQD3; |
639 | params.hsync_pct = VESAGTF_HSYNC_PCT8; |
640 | params.min_vsbp = VESAGTF_MIN_VSBP550; |
641 | params.M = VESAGTF_M600; |
642 | params.C = VESAGTF_C40; |
643 | params.K = VESAGTF_K128; |
644 | params.J = VESAGTF_J20; |
645 | |
646 | vesagtf_mode_params(x, y, refresh, ¶ms, 0, vmp); |
647 | } |
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 _KERNEL1 |
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 |