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Diffstat (limited to 'xorg-server/hw/xfree86/modes/xf86gtf.c')
| -rw-r--r-- | xorg-server/hw/xfree86/modes/xf86gtf.c | 384 |
1 files changed, 384 insertions, 0 deletions
diff --git a/xorg-server/hw/xfree86/modes/xf86gtf.c b/xorg-server/hw/xfree86/modes/xf86gtf.c new file mode 100644 index 000000000..acbac83b6 --- /dev/null +++ b/xorg-server/hw/xfree86/modes/xf86gtf.c @@ -0,0 +1,384 @@ +/* + * gtf.c Generate mode timings using the GTF Timing Standard + * + * gcc gtf.c -o gtf -lm -Wall + * + * Copyright (c) 2001, Andy Ritger aritger@nvidia.com + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * o Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * o Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer + * in the documentation and/or other materials provided with the + * distribution. + * o Neither the name of NVIDIA nor the names of its contributors + * may be used to endorse or promote products derived from this + * software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT + * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL + * THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * This program is based on the Generalized Timing Formula(GTF TM) + * Standard Version: 1.0, Revision: 1.0 + * + * The GTF Document contains the following Copyright information: + * + * Copyright (c) 1994, 1995, 1996 - Video Electronics Standards + * Association. Duplication of this document within VESA member + * companies for review purposes is permitted. All other rights + * reserved. + * + * While every precaution has been taken in the preparation + * of this standard, the Video Electronics Standards Association and + * its contributors assume no responsibility for errors or omissions, + * and make no warranties, expressed or implied, of functionality + * of suitability for any purpose. The sample code contained within + * this standard may be used without restriction. + * + * + * + * The GTF EXCEL(TM) SPREADSHEET, a sample (and the definitive) + * implementation of the GTF Timing Standard, is available at: + * + * ftp://ftp.vesa.org/pub/GTF/GTF_V1R1.xls + */ + +/* Ruthlessly converted to server code by Adam Jackson <ajax@redhat.com> */ + +#ifdef HAVE_XORG_CONFIG_H +# include <xorg-config.h> +#endif + +#include "xf86.h" +#include "xf86Modes.h" +#include <string.h> + +#define MARGIN_PERCENT 1.8 /* % of active vertical image */ +#define CELL_GRAN 8.0 /* assumed character cell granularity */ +#define MIN_PORCH 1 /* minimum front porch */ +#define V_SYNC_RQD 3 /* width of vsync in lines */ +#define H_SYNC_PERCENT 8.0 /* width of hsync as % of total line */ +#define MIN_VSYNC_PLUS_BP 550.0 /* min time of vsync + back porch (microsec) */ +#define M 600.0 /* blanking formula gradient */ +#define C 40.0 /* blanking formula offset */ +#define K 128.0 /* blanking formula scaling factor */ +#define J 20.0 /* blanking formula scaling factor */ + +/* C' and M' are part of the Blanking Duty Cycle computation */ + +#define C_PRIME (((C - J) * K/256.0) + J) +#define M_PRIME (K/256.0 * M) + + +/* + * xf86GTFMode() - as defined by the GTF Timing Standard, compute the + * Stage 1 Parameters using the vertical refresh frequency. In other + * words: input a desired resolution and desired refresh rate, and + * output the GTF mode timings. + * + * XXX All the code is in place to compute interlaced modes, but I don't + * feel like testing it right now. + * + * XXX margin computations are implemented but not tested (nor used by + * XServer of fbset mode descriptions, from what I can tell). + */ + +_X_EXPORT DisplayModePtr +xf86GTFMode(int h_pixels, int v_lines, float freq, int interlaced, int margins) +{ + DisplayModeRec *mode = xnfcalloc(1, sizeof(DisplayModeRec)); + + float h_pixels_rnd; + float v_lines_rnd; + float v_field_rate_rqd; + float top_margin; + float bottom_margin; + float interlace; + float h_period_est; + float vsync_plus_bp; + float v_back_porch; + float total_v_lines; + float v_field_rate_est; + float h_period; + float v_field_rate; + float v_frame_rate; + float left_margin; + float right_margin; + float total_active_pixels; + float ideal_duty_cycle; + float h_blank; + float total_pixels; + float pixel_freq; + float h_freq; + + float h_sync; + float h_front_porch; + float v_odd_front_porch_lines; + + /* 1. In order to give correct results, the number of horizontal + * pixels requested is first processed to ensure that it is divisible + * by the character size, by rounding it to the nearest character + * cell boundary: + * + * [H PIXELS RND] = ((ROUND([H PIXELS]/[CELL GRAN RND],0))*[CELLGRAN RND]) + */ + + h_pixels_rnd = rint((float) h_pixels / CELL_GRAN) * CELL_GRAN; + + /* 2. If interlace is requested, the number of vertical lines assumed + * by the calculation must be halved, as the computation calculates + * the number of vertical lines per field. In either case, the + * number of lines is rounded to the nearest integer. + * + * [V LINES RND] = IF([INT RQD?]="y", ROUND([V LINES]/2,0), + * ROUND([V LINES],0)) + */ + + v_lines_rnd = interlaced ? + rint((float) v_lines) / 2.0 : + rint((float) v_lines); + + /* 3. Find the frame rate required: + * + * [V FIELD RATE RQD] = IF([INT RQD?]="y", [I/P FREQ RQD]*2, + * [I/P FREQ RQD]) + */ + + v_field_rate_rqd = interlaced ? (freq * 2.0) : (freq); + + /* 4. Find number of lines in Top margin: + * + * [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y", + * ROUND(([MARGIN%]/100*[V LINES RND]),0), + * 0) + */ + + top_margin = margins ? rint(MARGIN_PERCENT / 100.0 * v_lines_rnd) : (0.0); + + /* 5. Find number of lines in Bottom margin: + * + * [BOT MARGIN (LINES)] = IF([MARGINS RQD?]="Y", + * ROUND(([MARGIN%]/100*[V LINES RND]),0), + * 0) + */ + + bottom_margin = margins ? rint(MARGIN_PERCENT/100.0 * v_lines_rnd) : (0.0); + + /* 6. If interlace is required, then set variable [INTERLACE]=0.5: + * + * [INTERLACE]=(IF([INT RQD?]="y",0.5,0)) + */ + + interlace = interlaced ? 0.5 : 0.0; + + /* 7. Estimate the Horizontal period + * + * [H PERIOD EST] = ((1/[V FIELD RATE RQD]) - [MIN VSYNC+BP]/1000000) / + * ([V LINES RND] + (2*[TOP MARGIN (LINES)]) + + * [MIN PORCH RND]+[INTERLACE]) * 1000000 + */ + + h_period_est = (((1.0/v_field_rate_rqd) - (MIN_VSYNC_PLUS_BP/1000000.0)) + / (v_lines_rnd + (2*top_margin) + MIN_PORCH + interlace) + * 1000000.0); + + /* 8. Find the number of lines in V sync + back porch: + * + * [V SYNC+BP] = ROUND(([MIN VSYNC+BP]/[H PERIOD EST]),0) + */ + + vsync_plus_bp = rint(MIN_VSYNC_PLUS_BP/h_period_est); + + /* 9. Find the number of lines in V back porch alone: + * + * [V BACK PORCH] = [V SYNC+BP] - [V SYNC RND] + * + * XXX is "[V SYNC RND]" a typo? should be [V SYNC RQD]? + */ + + v_back_porch = vsync_plus_bp - V_SYNC_RQD; + + /* 10. Find the total number of lines in Vertical field period: + * + * [TOTAL V LINES] = [V LINES RND] + [TOP MARGIN (LINES)] + + * [BOT MARGIN (LINES)] + [V SYNC+BP] + [INTERLACE] + + * [MIN PORCH RND] + */ + + total_v_lines = v_lines_rnd + top_margin + bottom_margin + vsync_plus_bp + + interlace + MIN_PORCH; + + /* 11. Estimate the Vertical field frequency: + * + * [V FIELD RATE EST] = 1 / [H PERIOD EST] / [TOTAL V LINES] * 1000000 + */ + + v_field_rate_est = 1.0 / h_period_est / total_v_lines * 1000000.0; + + /* 12. Find the actual horizontal period: + * + * [H PERIOD] = [H PERIOD EST] / ([V FIELD RATE RQD] / [V FIELD RATE EST]) + */ + + h_period = h_period_est / (v_field_rate_rqd / v_field_rate_est); + + /* 13. Find the actual Vertical field frequency: + * + * [V FIELD RATE] = 1 / [H PERIOD] / [TOTAL V LINES] * 1000000 + */ + + v_field_rate = 1.0 / h_period / total_v_lines * 1000000.0; + + /* 14. Find the Vertical frame frequency: + * + * [V FRAME RATE] = (IF([INT RQD?]="y", [V FIELD RATE]/2, [V FIELD RATE])) + */ + + v_frame_rate = interlaced ? v_field_rate / 2.0 : v_field_rate; + + /* 15. Find number of pixels in left margin: + * + * [LEFT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y", + * (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 / + * [CELL GRAN RND]),0)) * [CELL GRAN RND], + * 0)) + */ + + left_margin = margins ? + rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN : + 0.0; + + /* 16. Find number of pixels in right margin: + * + * [RIGHT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y", + * (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 / + * [CELL GRAN RND]),0)) * [CELL GRAN RND], + * 0)) + */ + + right_margin = margins ? + rint(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN) * CELL_GRAN : + 0.0; + + /* 17. Find total number of active pixels in image and left and right + * margins: + * + * [TOTAL ACTIVE PIXELS] = [H PIXELS RND] + [LEFT MARGIN (PIXELS)] + + * [RIGHT MARGIN (PIXELS)] + */ + + total_active_pixels = h_pixels_rnd + left_margin + right_margin; + + /* 18. Find the ideal blanking duty cycle from the blanking duty cycle + * equation: + * + * [IDEAL DUTY CYCLE] = [C'] - ([M']*[H PERIOD]/1000) + */ + + ideal_duty_cycle = C_PRIME - (M_PRIME * h_period / 1000.0); + + /* 19. Find the number of pixels in the blanking time to the nearest + * double character cell: + * + * [H BLANK (PIXELS)] = (ROUND(([TOTAL ACTIVE PIXELS] * + * [IDEAL DUTY CYCLE] / + * (100-[IDEAL DUTY CYCLE]) / + * (2*[CELL GRAN RND])), 0)) + * * (2*[CELL GRAN RND]) + */ + + h_blank = rint(total_active_pixels * + ideal_duty_cycle / + (100.0 - ideal_duty_cycle) / + (2.0 * CELL_GRAN)) * (2.0 * CELL_GRAN); + + /* 20. Find total number of pixels: + * + * [TOTAL PIXELS] = [TOTAL ACTIVE PIXELS] + [H BLANK (PIXELS)] + */ + + total_pixels = total_active_pixels + h_blank; + + /* 21. Find pixel clock frequency: + * + * [PIXEL FREQ] = [TOTAL PIXELS] / [H PERIOD] + */ + + pixel_freq = total_pixels / h_period; + + /* 22. Find horizontal frequency: + * + * [H FREQ] = 1000 / [H PERIOD] + */ + + h_freq = 1000.0 / h_period; + + + /* Stage 1 computations are now complete; I should really pass + the results to another function and do the Stage 2 + computations, but I only need a few more values so I'll just + append the computations here for now */ + + + /* 17. Find the number of pixels in the horizontal sync period: + * + * [H SYNC (PIXELS)] =(ROUND(([H SYNC%] / 100 * [TOTAL PIXELS] / + * [CELL GRAN RND]),0))*[CELL GRAN RND] + */ + + h_sync = rint(H_SYNC_PERCENT/100.0 * total_pixels / CELL_GRAN) * CELL_GRAN; + + /* 18. Find the number of pixels in the horizontal front porch period: + * + * [H FRONT PORCH (PIXELS)] = ([H BLANK (PIXELS)]/2)-[H SYNC (PIXELS)] + */ + + h_front_porch = (h_blank / 2.0) - h_sync; + + /* 36. Find the number of lines in the odd front porch period: + * + * [V ODD FRONT PORCH(LINES)]=([MIN PORCH RND]+[INTERLACE]) + */ + + v_odd_front_porch_lines = MIN_PORCH + interlace; + + /* finally, pack the results in the mode struct */ + + mode->HDisplay = (int) (h_pixels_rnd); + mode->HSyncStart = (int) (h_pixels_rnd + h_front_porch); + mode->HSyncEnd = (int) (h_pixels_rnd + h_front_porch + h_sync); + mode->HTotal = (int) (total_pixels); + mode->VDisplay = (int) (v_lines_rnd); + mode->VSyncStart = (int) (v_lines_rnd + v_odd_front_porch_lines); + mode->VSyncEnd = (int) (v_lines_rnd + v_odd_front_porch_lines + V_SYNC_RQD); + mode->VTotal = (int) (total_v_lines); + + mode->Clock = (int) (pixel_freq * 1000.0); + mode->HSync = h_freq; + mode->VRefresh = freq; + + xf86SetModeDefaultName(mode); + + mode->Flags = V_NHSYNC | V_PVSYNC; + if (interlaced) { + mode->VTotal *= 2; + mode->Flags |= V_INTERLACE; + } + + return mode; +} |