| 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 | |