#include "cvt.h" #ifdef __cplusplus extern "C" { #endif /* * Based on the cvt util: * http://www.uruk.org/projects/cvt/cvt.c */ #include #include #include #define CLOCK_STEP 0.25 /* Clock steps in MHz */ #define MARGIN_PERCENT 1.8 /* % of active vertical image */ #define H_SYNC_PER 8.0 /* sync % of horizontal image */ #define CELL_GRAN 8.4999 /* assumed character cell granularity */ #define CELL_GRAN_RND 8.0 /* assumed character cell granularity (round)*/ #define MIN_V_BPORCH 3.0 /* width of vsync in lines */ #define MIN_V_PORCH_RND 3.0 /* width of vsync in lines */ #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 */ /* Standard Timing Parameters */ #define MIN_VSYNC_BP 550.0 /* min time of vsync + back porch (us) */ #define H_SYNC_PERCENT 8.0 /* width of hsync as % of total line */ /* Reduced Blanking defines */ #define RB_MIN_V_BPORCH 6.0 /* lines */ #define RB_V_FPORCH 3.0 /* lines */ #define RB_MIN_V_BLANK 460.0 /* us */ #define RB_H_SYNC 32.0 /* pixels */ #define RB_H_BLANK 160.0 /* pixels */ /* 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) /* NOP out prints */ #define print_value(...) (void)0 typedef struct __options { int x, y; int reduced_blank, interlaced; int xf86mode, fbmode; float v_freq; } options; /* * vert_refresh() - as defined by the CVT 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 CVT mode timings. * * XXX margin computations are implemented but not tested (nor used by * XFree86 of fbset mode descriptions, from what I can tell). */ mode *vert_refresh (int h_pixels, int v_lines, float freq, int interlaced, int reduced_blank, int margins) { float h_pixels_rnd; float v_lines_rnd; float v_field_rate_rqd; float top_margin; float bot_margin; float interlace; float h_period_est; float v_sync_bp; float total_v_lines; float left_margin; float right_margin; float total_active_pixels; float ideal_duty_cycle; float h_blank; float total_pixels; float cur_duty_cycle; float v_sync; float v_sync_rnd, h_sync_rnd; float h_back_porch, v_front_porch, h_front_porch; float vbi_lines, act_vbi_lines, rb_min_vbi; float act_pixel_freq, act_h_freq; float act_field_rate, act_frame_rate; char *aspect_ratio; int stage; mode *m = (mode*) malloc (sizeof (mode)); /* 1. Required Field Rate * * This is slightly different from the spreadsheet because we use * a different result for interlaced video modes. Simplifies this * to the input field rate. * * [V FIELD RATE RQD] = [I/P FREQ RQD] */ v_field_rate_rqd = freq; print_value(1, "[V FIELD RATE RQD]", v_field_rate_rqd); /* 2. Horizontal Pixels * * 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] = ((ROUNDDOWN([H PIXELS]/[CELL GRAN RND],0)) * *[CELLGRAN RND]) */ h_pixels_rnd = floor((float) h_pixels / CELL_GRAN_RND) * CELL_GRAN_RND; print_value(2, "[H PIXELS RND]", h_pixels_rnd); /* 2.5th Calculation, aspect_ratio & v_sync_rnd * * [ASPECT_RATIO] = IF(H_PIXELS_RND = CELL_GRAN_RND*ROUND((V_LINES* * 4.0/3.0)/CELL_GRAN_RND),"4:3") * etc... * [V_SYNC] = [value from table based on aspect ratio] * [V_SYNC_RND] = ROUND(V_SYNC,0) // Not needed in principle */ if (h_pixels_rnd == CELL_GRAN_RND * floor(((float)v_lines * 4.0 / 3.0) / CELL_GRAN_RND)) { aspect_ratio = "4:3"; v_sync = 4; } else if (h_pixels_rnd == CELL_GRAN_RND * floor(((float)v_lines * 16.0 / 9.0) / CELL_GRAN_RND)) { aspect_ratio = "16:9"; v_sync = 5; } else if (h_pixels_rnd == CELL_GRAN_RND * floor(((float)v_lines * 16.0 / 10.0) / CELL_GRAN_RND)) { aspect_ratio = "16:10"; v_sync = 6; } else if (h_pixels_rnd == CELL_GRAN_RND * floor(((float)v_lines * 5.0 / 4.0) / CELL_GRAN_RND)) { aspect_ratio = "5:4"; v_sync = 7; } else if (h_pixels_rnd == CELL_GRAN_RND * floor(((float)v_lines * 15.0 / 9.0) / CELL_GRAN_RND)) { aspect_ratio = "15:9"; v_sync = 7; } else { /* Default case of unknown aspect ratio */ aspect_ratio = "Custom"; v_sync = 10; } v_sync_rnd = v_sync; /* * 3. Determine Left & Right Borders * * Calculate the margins on the left and right side. * * [LEFT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y", * (ROUNDDOWN( ([H PIXELS RND] * [MARGIN%] / 100 / * [CELL GRAN RND]),0)) * [CELL GRAN RND], * 0)) * [RIGHT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y", * (ROUNDDOWN( ([H PIXELS RND] * [MARGIN%] / 100 / * [CELL GRAN RND]),0)) * [CELL GRAN RND], * 0)) */ left_margin = margins ? floor(h_pixels_rnd * MARGIN_PERCENT / 100.0 / CELL_GRAN_RND) * CELL_GRAN_RND : 0.0; right_margin = left_margin; print_value(3, "[LEFT MARGIN (PIXELS)]", left_margin); print_value(3, "[RIGHT MARGIN (PIXELS)]", right_margin); /* 4. Find total active pixels. * * 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; print_value(4, "[TOTAL ACTIVE PIXELS]", total_active_pixels); /* 5. Find number of lines per field. * * 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", ROUNDDOWN([V LINES]/2,0), * ROUNDDOWN([V LINES],0)) */ v_lines_rnd = interlaced ? floor((float) v_lines / 2.0) : floor((float) v_lines); print_value(5, "[V LINES RND]", v_lines_rnd); /* 6. Find Top and Bottom margins. * * [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y", * ROUNDDOWN(([MARGIN%]/100*[V LINES RND]),0), * 0) * [BOT MARGIN (LINES)] = IF([MARGINS RQD?]="Y", * ROUNDDOWN(([MARGIN%]/100*[V LINES RND]),0), * 0) */ top_margin = margins ? floor(MARGIN_PERCENT / 100.0 * v_lines_rnd) : (0.0); bot_margin = top_margin; print_value(6, "[TOP MARGIN (LINES)]", top_margin); print_value(6, "[BOT MARGIN (LINES)]", bot_margin); /* 7. If interlace is required, then set variable [INTERLACE]=0.5: * * [INTERLACE]=(IF([INT RQD?]="y",0.5,0)) */ interlace = interlaced ? 0.5 : 0.0; print_value(7, "[INTERLACE]", interlace); /* * Here it diverges for "reduced blanking" or normal blanking modes. */ if (reduced_blank) { h_blank = RB_H_BLANK; /* 8. Estimate Horiz. Period (us). * * [H PERIOD EST] = ((1000000/V_FIELD_RATE_RQD)-RB_MIN_V_BLANK)/(V_LINES_RND+TOP_MARGIN+BOT_MARGIN) */ h_period_est = (1000000.0/v_field_rate_rqd - RB_MIN_V_BLANK) / (v_lines_rnd + top_margin + bot_margin); print_value(8, "[H PERIOD EST]", h_period_est); /* 9. Find number of lines in vertical blanking. * * [Actual VBI_LINES] = RB_MIN_V_BLANK/H_PERIOD_EST * [VBI_LINES] = ROUNDDOWN(RB_MIN_V_BLANK/H_PERIOD_EST,0) + 1 */ vbi_lines = RB_MIN_V_BLANK/h_period_est; print_value(9, "[Actual VBI LINES]", vbi_lines); vbi_lines = floor(vbi_lines) + 1.0; print_value(9, "[VBI LINES]", vbi_lines); /* 10. Check Vertical Blanking is sufficient. * * [RB MIN VBI] = RB_V_FPORCH+V_SYNC_RND+RB_MIN_V_BPORCH * [ACT VBI LINES] = IF(VBI_LINEShr = (int) (h_pixels_rnd); m->hss = (int) (h_pixels_rnd + h_front_porch); m->hse = (int) (h_pixels_rnd + h_front_porch + h_sync_rnd); m->hfl = (int) (total_pixels); #if 0 m->vr = (int) (v_lines_rnd); m->vss = (int) (v_lines_rnd + v_front_porch); m->vse = (int) (v_lines_rnd + v_front_porch + v_sync_rnd); m->vfl = (int) (total_v_lines); #else { int real_v_lines = v_lines; m->vr = (int) (real_v_lines); m->vss = (int) (real_v_lines + v_front_porch); m->vse = (int) (real_v_lines + v_front_porch + v_sync_rnd); m->vfl = (int) (total_v_lines - v_lines_rnd + real_v_lines); } #endif m->pclk = act_pixel_freq; m->h_freq = act_h_freq; m->v_freq = freq; m->real_v_rate = act_field_rate; m->in = interlaced; m->rb = reduced_blank; return (m); } // vert_refresh() #ifdef __cplusplus } #endif