calc-gtf-cvt.cpp - platform/external/edid-decode - Git at Google

 // SPDX-License-Identifier: MIT
 /*
  * Copyright 2006-2012 Red Hat, Inc.
  * Copyright 2018-2021 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
  *
  * Author: Adam Jackson <[email protected]>
  * Maintainer: Hans Verkuil <[email protected]>
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
 #include <time.h>

 #include "edid-decode.h"

 #define CELL_GRAN 8.0
 #define MARGIN_PERC 1.8
 #define GTF_MIN_PORCH 1.0
 #define GTF_V_SYNC_RQD 3.0
 #define GTF_H_SYNC_PERC 8.0
 #define GTF_MIN_VSYNC_BP 550.0

 timings edid_state::calc_gtf_mode(unsigned h_pixels, unsigned v_lines,
 				  double ip_freq_rqd, bool int_rqd,
 				  enum gtf_ip_parm ip_parm, bool margins_rqd,
 				  bool secondary, double C, double M, double K, double J)
 {
 	timings t = {};
 	/* C' and M' are part of the Blanking Duty Cycle computation */
 	double C_PRIME = ((C - J) * K / 256.0) + J;
 	double M_PRIME = K / 256.0 * M;

 	double h_pixels_rnd = round(h_pixels / CELL_GRAN) * CELL_GRAN;
 	double v_lines_rnd = int_rqd ? round(v_lines / 2.0) : v_lines;
 	unsigned hor_margin = margins_rqd ?
 		round(h_pixels_rnd * MARGIN_PERC / 100.0 / CELL_GRAN)  * CELL_GRAN : 0;
 	unsigned vert_margin = margins_rqd ? round(MARGIN_PERC / 100.0 * v_lines_rnd) : 0;
 	double interlace = int_rqd ? 0.5 : 0;
 	double total_active_pixels = h_pixels_rnd + hor_margin * 2;

 	t.hact = h_pixels_rnd;
 	t.vact = v_lines;
 	t.interlaced = int_rqd;

 	double pixel_freq;
 	double h_blank_pixels;
 	double total_pixels;
 	double v_sync_bp;

 	if (ip_parm == gtf_ip_vert_freq) {
 		// vertical frame frequency (Hz)
 		double v_field_rate_rqd = int_rqd ? ip_freq_rqd * 2 : ip_freq_rqd;
 		double h_period_est = ((1.0 / v_field_rate_rqd) - GTF_MIN_VSYNC_BP / 1000000.0) /
 			(v_lines_rnd + vert_margin * 2 + GTF_MIN_PORCH + interlace) * 1000000.0;
 		v_sync_bp = round(GTF_MIN_VSYNC_BP / h_period_est);
 		double total_v_lines = v_lines_rnd + vert_margin * 2 +
 			v_sync_bp + interlace + GTF_MIN_PORCH;
 		double v_field_rate_est = 1.0 / h_period_est / total_v_lines * 1000000.0;
 		double h_period = h_period_est / (v_field_rate_rqd / v_field_rate_est);
 		double ideal_duty_cycle = C_PRIME - (M_PRIME * h_period / 1000.0);
 		h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
 				       (100.0 - ideal_duty_cycle) /
 				       (2 * CELL_GRAN)) * 2 * CELL_GRAN;
 		total_pixels = total_active_pixels + h_blank_pixels;
 		pixel_freq = total_pixels / h_period;
 	} else if (ip_parm == gtf_ip_hor_freq) {
 		// horizontal frequency (kHz)
 		double h_freq = ip_freq_rqd;
 		v_sync_bp = round(GTF_MIN_VSYNC_BP * h_freq / 1000.0);
 		double ideal_duty_cycle = C_PRIME - (M_PRIME / h_freq);
 		h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
 				       (100.0 - ideal_duty_cycle) /
 				       (2 * CELL_GRAN)) * 2 * CELL_GRAN;
 		total_pixels = total_active_pixels + h_blank_pixels;
 		pixel_freq = total_pixels * h_freq / 1000.0;
 	} else {
 		// pixel clock rate (MHz)
 		pixel_freq = ip_freq_rqd;
 		double ideal_h_period =
 			((C_PRIME - 100.0) +
 			 sqrt(((100.0 - C_PRIME) * (100.0 - C_PRIME) +
 			       (0.4 * M_PRIME * (total_active_pixels + hor_margin * 2) /
 				pixel_freq)))) / 2.0 / M_PRIME * 1000.0;
 		double ideal_duty_cycle = C_PRIME - (M_PRIME * ideal_h_period) / 1000.0;
 		h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
 				       (100.0 - ideal_duty_cycle) /
 				       (2 * CELL_GRAN)) * 2 * CELL_GRAN;
 		total_pixels = total_active_pixels + h_blank_pixels;
 		double h_freq = pixel_freq / total_pixels * 1000.0;
 		v_sync_bp = round(GTF_MIN_VSYNC_BP * h_freq / 1000.0);
 	}

 	double v_back_porch = v_sync_bp - GTF_V_SYNC_RQD;

 	t.vbp = v_back_porch;
 	t.vsync = GTF_V_SYNC_RQD;
 	t.vfp = GTF_MIN_PORCH;
 	t.pixclk_khz = round(1000.0 * pixel_freq);
 	t.hsync = round(GTF_H_SYNC_PERC / 100.0 * total_pixels / CELL_GRAN) * CELL_GRAN;
 	t.hfp = (h_blank_pixels / 2.0) - t.hsync;
 	t.hbp = t.hfp + t.hsync;
 	t.hborder = hor_margin;
 	t.vborder = vert_margin;
 	t.pos_pol_hsync = secondary;
 	t.pos_pol_vsync = !secondary;
 	t.rb = secondary ? RB_GTF : RB_NONE;
 	return t;
 }

 void edid_state::edid_gtf_mode(unsigned refresh, struct timings &t)
 {
 	unsigned hratio = t.hratio;
 	unsigned vratio = t.vratio;
 	t = calc_gtf_mode(t.hact, t.vact, refresh, t.interlaced);
 	t.hratio = hratio;
 	t.vratio = vratio;
 }

 #define CVT_MIN_VSYNC_BP 550.0
 #define CVT_MIN_V_PORCH 3
 #define CVT_MIN_V_BPORCH 6
 #define CVT_C_PRIME 30.0
 #define CVT_M_PRIME 300.0
 #define CVT_RB_MIN_VBLANK 460.0

 // If rb == RB_CVT_V2, then alt means video-optimized (i.e. 59.94 instead of 60 Hz, etc.).
 // If rb == RB_CVT_V3, then alt means that rb_h_blank is 160 instead of 80.
 timings edid_state::calc_cvt_mode(unsigned h_pixels, unsigned v_lines,
 				  double ip_freq_rqd, unsigned rb, bool int_rqd,
 				  bool margins_rqd, bool alt, unsigned rb_h_blank)
 {
 	timings t = {};

 	t.hact = h_pixels;
 	t.vact = v_lines;
 	t.interlaced = int_rqd;

 	double cell_gran = rb == RB_CVT_V2 ? 1 : CELL_GRAN;
 	double h_pixels_rnd = floor(h_pixels / cell_gran) * cell_gran;
 	double v_lines_rnd = int_rqd ? floor(v_lines / 2.0) : v_lines;
 	unsigned hor_margin = margins_rqd ?
 		floor((h_pixels_rnd * MARGIN_PERC / 100.0) / cell_gran) * cell_gran : 0;
 	unsigned vert_margin = margins_rqd ? floor(MARGIN_PERC / 100.0 * v_lines_rnd) : 0;
 	double interlace = int_rqd ? 0.5 : 0;
 	double total_active_pixels = h_pixels_rnd + hor_margin * 2;
 	double v_field_rate_rqd = int_rqd ? ip_freq_rqd * 2 : ip_freq_rqd;
 	double clock_step = rb == RB_CVT_V2 ? 0.001 : 0.25;
 	double h_blank = (rb == RB_CVT_V1 || (rb == RB_CVT_V3 && alt)) ? 160 : 80;
 	double rb_v_fporch = rb == RB_CVT_V1 ? 3 : 1;
 	double refresh_multiplier = (rb == RB_CVT_V2 && alt) ? 1000.0 / 1001.0 : 1;
 	double h_sync = 32;

 	double v_sync;
 	double pixel_freq;
 	double v_blank;
 	double v_sync_bp;

 	if (rb == RB_CVT_V3 && rb_h_blank) {
 		h_blank = rb_h_blank & ~7;
 		if (h_blank < 80)
 			h_blank = 80;
 		else if (h_blank > 200)
 			h_blank = 200;
 	}

 	/* Determine VSync Width from aspect ratio */
 	if ((t.vact * 4 / 3) == t.hact)
 		v_sync = 4;
 	else if ((t.vact * 16 / 9) == t.hact)
 		v_sync = 5;
 	else if ((t.vact * 16 / 10) == t.hact)
 		v_sync = 6;
 	else if (!(t.vact % 4) && ((t.vact * 5 / 4) == t.hact))
 		v_sync = 7;
 	else if ((t.vact * 15 / 9) == t.hact)
 		v_sync = 7;
 	else                        /* Custom */
 		v_sync = 10;

 	if (rb >= RB_CVT_V2)
 		v_sync = 8;

 	if (rb == RB_NONE) {
 		double h_period_est = ((1.0 / v_field_rate_rqd) - CVT_MIN_VSYNC_BP / 1000000.0) /
 			(v_lines_rnd + vert_margin * 2 + CVT_MIN_V_PORCH + interlace) * 1000000.0;
 		v_sync_bp = floor(CVT_MIN_VSYNC_BP / h_period_est) + 1;
 		if (v_sync_bp < v_sync + CVT_MIN_V_BPORCH)
 			v_sync_bp = v_sync + CVT_MIN_V_BPORCH;
 		v_blank = v_sync_bp + CVT_MIN_V_PORCH;
 		double ideal_duty_cycle = CVT_C_PRIME - (CVT_M_PRIME * h_period_est / 1000.0);
 		if (ideal_duty_cycle < 20)
 			ideal_duty_cycle = 20;
 		h_blank = floor(total_active_pixels * ideal_duty_cycle /
 				(100.0 - ideal_duty_cycle) /
 				(2 * CELL_GRAN)) * 2 * CELL_GRAN;
 		double total_pixels = total_active_pixels + h_blank;
 		h_sync = floor(total_pixels * 0.08 / CELL_GRAN) * CELL_GRAN;
 		pixel_freq = floor((total_pixels / h_period_est) / clock_step) * clock_step;
 	} else {
 		double h_period_est = ((1000000.0 / v_field_rate_rqd) - CVT_RB_MIN_VBLANK) /
 					(v_lines_rnd + vert_margin * 2);
 		double vbi_lines = floor(CVT_RB_MIN_VBLANK / h_period_est) + 1;
 		double rb_min_vbi = rb_v_fporch + v_sync + CVT_MIN_V_BPORCH;
 		v_blank = vbi_lines < rb_min_vbi ? rb_min_vbi : vbi_lines;
 		double total_v_lines = v_blank + v_lines_rnd + vert_margin * 2 + interlace;
 		if (rb == RB_CVT_V1)
 			v_sync_bp = v_blank - rb_v_fporch;
 		else
 			v_sync_bp = v_sync + CVT_MIN_V_BPORCH;
 		double total_pixels = h_blank + total_active_pixels;
 		double freq = v_field_rate_rqd * total_v_lines * total_pixels * refresh_multiplier;
 		if (rb == RB_CVT_V3)
 			pixel_freq = ceil((freq / 1000000.0) / clock_step) * clock_step;
 		else
 			pixel_freq = floor((freq / 1000000.0) / clock_step) * clock_step;
 	}

 	t.vbp = v_sync_bp - v_sync;
 	t.vsync = v_sync;
 	t.vfp = v_blank - t.vbp - t.vsync;
 	t.pixclk_khz = round(1000.0 * pixel_freq);
 	t.hsync = h_sync;
 	if (rb == RB_CVT_V3)
 		t.hfp = 8;
 	else
 		t.hfp = (h_blank / 2.0) - t.hsync;
 	t.hbp = h_blank - t.hfp - t.hsync;
 	t.hborder = hor_margin;
 	t.vborder = vert_margin;
 	t.rb = rb;
 	if (alt && (rb == RB_CVT_V2 || rb == RB_CVT_V3))
 		t.rb |= RB_ALT;
 	t.pos_pol_hsync = t.rb;
 	t.pos_pol_vsync = !t.rb;
 	calc_ratio(&t);
 	return t;
 }

 void edid_state::edid_cvt_mode(unsigned refresh, struct timings &t)
 {
 	unsigned hratio = t.hratio;
 	unsigned vratio = t.vratio;

 	t = calc_cvt_mode(t.hact, t.vact, refresh, t.rb & ~RB_ALT, t.interlaced,
 			  false, t.rb & RB_ALT);
 	t.hratio = hratio;
 	t.vratio = vratio;
 }
	// SPDX-License-Identifier: MIT
	/*
	* Copyright 2006-2012 Red Hat, Inc.
	* Copyright 2018-2021 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
	*
	* Author: Adam Jackson <[email protected]>
	* Maintainer: Hans Verkuil <[email protected]>
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <math.h>
	#include <time.h>

	#include "edid-decode.h"

	#define CELL_GRAN 8.0
	#define MARGIN_PERC 1.8
	#define GTF_MIN_PORCH 1.0
	#define GTF_V_SYNC_RQD 3.0
	#define GTF_H_SYNC_PERC 8.0
	#define GTF_MIN_VSYNC_BP 550.0

	timings edid_state::calc_gtf_mode(unsigned h_pixels, unsigned v_lines,
	double ip_freq_rqd, bool int_rqd,
	enum gtf_ip_parm ip_parm, bool margins_rqd,
	bool secondary, double C, double M, double K, double J)
	{
	timings t = {};
	/* C' and M' are part of the Blanking Duty Cycle computation */
	double C_PRIME = ((C - J) * K / 256.0) + J;
	double M_PRIME = K / 256.0 * M;

	double h_pixels_rnd = round(h_pixels / CELL_GRAN) * CELL_GRAN;
	double v_lines_rnd = int_rqd ? round(v_lines / 2.0) : v_lines;
	unsigned hor_margin = margins_rqd ?
	round(h_pixels_rnd * MARGIN_PERC / 100.0 / CELL_GRAN) * CELL_GRAN : 0;
	unsigned vert_margin = margins_rqd ? round(MARGIN_PERC / 100.0 * v_lines_rnd) : 0;
	double interlace = int_rqd ? 0.5 : 0;
	double total_active_pixels = h_pixels_rnd + hor_margin * 2;

	t.hact = h_pixels_rnd;
	t.vact = v_lines;
	t.interlaced = int_rqd;

	double pixel_freq;
	double h_blank_pixels;
	double total_pixels;
	double v_sync_bp;

	if (ip_parm == gtf_ip_vert_freq) {
	// vertical frame frequency (Hz)
	double v_field_rate_rqd = int_rqd ? ip_freq_rqd * 2 : ip_freq_rqd;
	double h_period_est = ((1.0 / v_field_rate_rqd) - GTF_MIN_VSYNC_BP / 1000000.0) /
	(v_lines_rnd + vert_margin * 2 + GTF_MIN_PORCH + interlace) * 1000000.0;
	v_sync_bp = round(GTF_MIN_VSYNC_BP / h_period_est);
	double total_v_lines = v_lines_rnd + vert_margin * 2 +
	v_sync_bp + interlace + GTF_MIN_PORCH;
	double v_field_rate_est = 1.0 / h_period_est / total_v_lines * 1000000.0;
	double h_period = h_period_est / (v_field_rate_rqd / v_field_rate_est);
	double ideal_duty_cycle = C_PRIME - (M_PRIME * h_period / 1000.0);
	h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
	(100.0 - ideal_duty_cycle) /
	(2 * CELL_GRAN)) * 2 * CELL_GRAN;
	total_pixels = total_active_pixels + h_blank_pixels;
	pixel_freq = total_pixels / h_period;
	} else if (ip_parm == gtf_ip_hor_freq) {
	// horizontal frequency (kHz)
	double h_freq = ip_freq_rqd;
	v_sync_bp = round(GTF_MIN_VSYNC_BP * h_freq / 1000.0);
	double ideal_duty_cycle = C_PRIME - (M_PRIME / h_freq);
	h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
	(100.0 - ideal_duty_cycle) /
	(2 * CELL_GRAN)) * 2 * CELL_GRAN;
	total_pixels = total_active_pixels + h_blank_pixels;
	pixel_freq = total_pixels * h_freq / 1000.0;
	} else {
	// pixel clock rate (MHz)
	pixel_freq = ip_freq_rqd;
	double ideal_h_period =
	((C_PRIME - 100.0) +
	sqrt(((100.0 - C_PRIME) * (100.0 - C_PRIME) +
	(0.4 * M_PRIME * (total_active_pixels + hor_margin * 2) /
	pixel_freq)))) / 2.0 / M_PRIME * 1000.0;
	double ideal_duty_cycle = C_PRIME - (M_PRIME * ideal_h_period) / 1000.0;
	h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
	(100.0 - ideal_duty_cycle) /
	(2 * CELL_GRAN)) * 2 * CELL_GRAN;
	total_pixels = total_active_pixels + h_blank_pixels;
	double h_freq = pixel_freq / total_pixels * 1000.0;
	v_sync_bp = round(GTF_MIN_VSYNC_BP * h_freq / 1000.0);
	}

	double v_back_porch = v_sync_bp - GTF_V_SYNC_RQD;

	t.vbp = v_back_porch;
	t.vsync = GTF_V_SYNC_RQD;
	t.vfp = GTF_MIN_PORCH;
	t.pixclk_khz = round(1000.0 * pixel_freq);
	t.hsync = round(GTF_H_SYNC_PERC / 100.0 * total_pixels / CELL_GRAN) * CELL_GRAN;
	t.hfp = (h_blank_pixels / 2.0) - t.hsync;
	t.hbp = t.hfp + t.hsync;
	t.hborder = hor_margin;
	t.vborder = vert_margin;
	t.pos_pol_hsync = secondary;
	t.pos_pol_vsync = !secondary;
	t.rb = secondary ? RB_GTF : RB_NONE;
	return t;
	}

	void edid_state::edid_gtf_mode(unsigned refresh, struct timings &t)
	{
	unsigned hratio = t.hratio;
	unsigned vratio = t.vratio;
	t = calc_gtf_mode(t.hact, t.vact, refresh, t.interlaced);
	t.hratio = hratio;
	t.vratio = vratio;
	}

	#define CVT_MIN_VSYNC_BP 550.0
	#define CVT_MIN_V_PORCH 3
	#define CVT_MIN_V_BPORCH 6
	#define CVT_C_PRIME 30.0
	#define CVT_M_PRIME 300.0
	#define CVT_RB_MIN_VBLANK 460.0

	// If rb == RB_CVT_V2, then alt means video-optimized (i.e. 59.94 instead of 60 Hz, etc.).
	// If rb == RB_CVT_V3, then alt means that rb_h_blank is 160 instead of 80.
	timings edid_state::calc_cvt_mode(unsigned h_pixels, unsigned v_lines,
	double ip_freq_rqd, unsigned rb, bool int_rqd,
	bool margins_rqd, bool alt, unsigned rb_h_blank)
	{
	timings t = {};

	t.hact = h_pixels;
	t.vact = v_lines;
	t.interlaced = int_rqd;

	double cell_gran = rb == RB_CVT_V2 ? 1 : CELL_GRAN;
	double h_pixels_rnd = floor(h_pixels / cell_gran) * cell_gran;
	double v_lines_rnd = int_rqd ? floor(v_lines / 2.0) : v_lines;
	unsigned hor_margin = margins_rqd ?
	floor((h_pixels_rnd * MARGIN_PERC / 100.0) / cell_gran) * cell_gran : 0;
	unsigned vert_margin = margins_rqd ? floor(MARGIN_PERC / 100.0 * v_lines_rnd) : 0;
	double interlace = int_rqd ? 0.5 : 0;
	double total_active_pixels = h_pixels_rnd + hor_margin * 2;
	double v_field_rate_rqd = int_rqd ? ip_freq_rqd * 2 : ip_freq_rqd;
	double clock_step = rb == RB_CVT_V2 ? 0.001 : 0.25;
	double h_blank = (rb == RB_CVT_V1 \|\| (rb == RB_CVT_V3 && alt)) ? 160 : 80;
	double rb_v_fporch = rb == RB_CVT_V1 ? 3 : 1;
	double refresh_multiplier = (rb == RB_CVT_V2 && alt) ? 1000.0 / 1001.0 : 1;
	double h_sync = 32;

	double v_sync;
	double pixel_freq;
	double v_blank;
	double v_sync_bp;

	if (rb == RB_CVT_V3 && rb_h_blank) {
	h_blank = rb_h_blank & ~7;
	if (h_blank < 80)
	h_blank = 80;
	else if (h_blank > 200)
	h_blank = 200;
	}

	/* Determine VSync Width from aspect ratio */
	if ((t.vact * 4 / 3) == t.hact)
	v_sync = 4;
	else if ((t.vact * 16 / 9) == t.hact)
	v_sync = 5;
	else if ((t.vact * 16 / 10) == t.hact)
	v_sync = 6;
	else if (!(t.vact % 4) && ((t.vact * 5 / 4) == t.hact))
	v_sync = 7;
	else if ((t.vact * 15 / 9) == t.hact)
	v_sync = 7;
	else /* Custom */
	v_sync = 10;

	if (rb >= RB_CVT_V2)
	v_sync = 8;

	if (rb == RB_NONE) {
	double h_period_est = ((1.0 / v_field_rate_rqd) - CVT_MIN_VSYNC_BP / 1000000.0) /
	(v_lines_rnd + vert_margin * 2 + CVT_MIN_V_PORCH + interlace) * 1000000.0;
	v_sync_bp = floor(CVT_MIN_VSYNC_BP / h_period_est) + 1;
	if (v_sync_bp < v_sync + CVT_MIN_V_BPORCH)
	v_sync_bp = v_sync + CVT_MIN_V_BPORCH;
	v_blank = v_sync_bp + CVT_MIN_V_PORCH;
	double ideal_duty_cycle = CVT_C_PRIME - (CVT_M_PRIME * h_period_est / 1000.0);
	if (ideal_duty_cycle < 20)
	ideal_duty_cycle = 20;
	h_blank = floor(total_active_pixels * ideal_duty_cycle /
	(100.0 - ideal_duty_cycle) /
	(2 * CELL_GRAN)) * 2 * CELL_GRAN;
	double total_pixels = total_active_pixels + h_blank;
	h_sync = floor(total_pixels * 0.08 / CELL_GRAN) * CELL_GRAN;
	pixel_freq = floor((total_pixels / h_period_est) / clock_step) * clock_step;
	} else {
	double h_period_est = ((1000000.0 / v_field_rate_rqd) - CVT_RB_MIN_VBLANK) /
	(v_lines_rnd + vert_margin * 2);
	double vbi_lines = floor(CVT_RB_MIN_VBLANK / h_period_est) + 1;
	double rb_min_vbi = rb_v_fporch + v_sync + CVT_MIN_V_BPORCH;
	v_blank = vbi_lines < rb_min_vbi ? rb_min_vbi : vbi_lines;
	double total_v_lines = v_blank + v_lines_rnd + vert_margin * 2 + interlace;
	if (rb == RB_CVT_V1)
	v_sync_bp = v_blank - rb_v_fporch;
	else
	v_sync_bp = v_sync + CVT_MIN_V_BPORCH;
	double total_pixels = h_blank + total_active_pixels;
	double freq = v_field_rate_rqd * total_v_lines * total_pixels * refresh_multiplier;
	if (rb == RB_CVT_V3)
	pixel_freq = ceil((freq / 1000000.0) / clock_step) * clock_step;
	else
	pixel_freq = floor((freq / 1000000.0) / clock_step) * clock_step;
	}

	t.vbp = v_sync_bp - v_sync;
	t.vsync = v_sync;
	t.vfp = v_blank - t.vbp - t.vsync;
	t.pixclk_khz = round(1000.0 * pixel_freq);
	t.hsync = h_sync;
	if (rb == RB_CVT_V3)
	t.hfp = 8;
	else
	t.hfp = (h_blank / 2.0) - t.hsync;
	t.hbp = h_blank - t.hfp - t.hsync;
	t.hborder = hor_margin;
	t.vborder = vert_margin;
	t.rb = rb;
	if (alt && (rb == RB_CVT_V2 \|\| rb == RB_CVT_V3))
	t.rb \|= RB_ALT;
	t.pos_pol_hsync = t.rb;
	t.pos_pol_vsync = !t.rb;
	calc_ratio(&t);
	return t;
	}

	void edid_state::edid_cvt_mode(unsigned refresh, struct timings &t)
	{
	unsigned hratio = t.hratio;
	unsigned vratio = t.vratio;

	t = calc_cvt_mode(t.hact, t.vact, refresh, t.rb & ~RB_ALT, t.interlaced,
	false, t.rb & RB_ALT);
	t.hratio = hratio;
	t.vratio = vratio;
	}