| 1 | |
| 2 | * linux/drivers/video/fbcvt.c - VESA(TM) Coordinated Video Timings
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| 3 | *
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| 4 | * Copyright (C) 2005 Antonino Daplas <[email protected]>
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| 5 | *
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| 6 | * Based from the VESA(TM) Coordinated Video Timing Generator by
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| 7 | * Graham Loveridge April 9, 2003 available at
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| 8 | * http://www.elo.utfsm.cl/~elo212/docs/CVTd6r1.xls
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| 9 | *
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| 10 | * This file is subject to the terms and conditions of the GNU General Public
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| 11 | * License. See the file COPYING in the main directory of this archive
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| 12 | * for more details.
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| 13 | *
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| 14 |
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| 15 | #include <linux/fb.h>
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| 16 | #include <linux/slab.h>
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| 17 |
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| 18 | #define FB_CVT_CELLSIZE 8
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| 19 | #define FB_CVT_GTF_C 40
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| 20 | #define FB_CVT_GTF_J 20
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| 21 | #define FB_CVT_GTF_K 128
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| 22 | #define FB_CVT_GTF_M 600
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| 23 | #define FB_CVT_MIN_VSYNC_BP 550
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| 24 | #define FB_CVT_MIN_VPORCH 3
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| 25 | #define FB_CVT_MIN_BPORCH 6
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| 26 |
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| 27 | #define FB_CVT_RB_MIN_VBLANK 460
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| 28 | #define FB_CVT_RB_HBLANK 160
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| 29 | #define FB_CVT_RB_V_FPORCH 3
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| 30 |
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| 31 | #define FB_CVT_FLAG_REDUCED_BLANK 1
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| 32 | #define FB_CVT_FLAG_MARGINS 2
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| 33 | #define FB_CVT_FLAG_INTERLACED 4
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| 34 |
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| 35 | struct fb_cvt_data {
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| 36 | u32 xres;
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| 37 | u32 yres;
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| 38 | u32 refresh;
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| 39 | u32 f_refresh;
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| 40 | u32 pixclock;
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| 41 | u32 hperiod;
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| 42 | u32 hblank;
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| 43 | u32 hfreq;
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| 44 | u32 htotal;
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| 45 | u32 vtotal;
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| 46 | u32 vsync;
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| 47 | u32 hsync;
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| 48 | u32 h_front_porch;
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| 49 | u32 h_back_porch;
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| 50 | u32 v_front_porch;
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| 51 | u32 v_back_porch;
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| 52 | u32 h_margin;
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| 53 | u32 v_margin;
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| 54 | u32 interlace;
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| 55 | u32 aspect_ratio;
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| 56 | u32 active_pixels;
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| 57 | u32 flags;
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| 58 | u32 status;
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| 59 | };
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| 60 |
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| 61 | static const unsigned char fb_cvt_vbi_tab[] = {
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| 62 | 4,
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| 63 | 5,
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| 64 | 6,
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| 65 | 7,
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| 66 | 7,
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| 67 | 8,
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| 68 | 9,
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| 69 | 10
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| 70 | };
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| 71 |
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| 72 |
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| 73 | static u32 fb_cvt_hperiod(struct fb_cvt_data *cvt)
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| 74 | {
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| 75 | u32 num = 1000000000/cvt->f_refresh;
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| 76 | u32 den;
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| 77 |
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| 78 | if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) {
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| 79 | num -= FB_CVT_RB_MIN_VBLANK * 1000;
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| 80 | den = 2 * (cvt->yres/cvt->interlace + 2 * cvt->v_margin);
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| 81 | } else {
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| 82 | num -= FB_CVT_MIN_VSYNC_BP * 1000;
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| 83 | den = 2 * (cvt->yres/cvt->interlace + cvt->v_margin * 2
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| 84 | + FB_CVT_MIN_VPORCH + cvt->interlace/2);
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| 85 | }
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| 86 |
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| 87 | return 2 * (num/den);
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| 88 | }
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| 89 |
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| 90 |
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| 91 | static u32 fb_cvt_ideal_duty_cycle(struct fb_cvt_data *cvt)
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| 92 | {
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| 93 | u32 c_prime = (FB_CVT_GTF_C - FB_CVT_GTF_J) *
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| 94 | (FB_CVT_GTF_K) + 256 * FB_CVT_GTF_J;
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| 95 | u32 m_prime = (FB_CVT_GTF_K * FB_CVT_GTF_M);
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| 96 | u32 h_period_est = cvt->hperiod;
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| 97 |
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| 98 | return (1000 * c_prime - ((m_prime * h_period_est)/1000))/256;
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| 99 | }
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| 100 |
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| 101 | static u32 fb_cvt_hblank(struct fb_cvt_data *cvt)
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| 102 | {
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| 103 | u32 hblank = 0;
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| 104 |
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| 105 | if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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| 106 | hblank = FB_CVT_RB_HBLANK;
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| 107 | else {
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| 108 | u32 ideal_duty_cycle = fb_cvt_ideal_duty_cycle(cvt);
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| 109 | u32 active_pixels = cvt->active_pixels;
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| 110 |
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| 111 | if (ideal_duty_cycle < 20000)
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| 112 | hblank = (active_pixels * 20000)/
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| 113 | (100000 - 20000);
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| 114 | else {
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| 115 | hblank = (active_pixels * ideal_duty_cycle)/
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| 116 | (100000 - ideal_duty_cycle);
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| 117 | }
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| 118 | }
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| 119 |
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| 120 | hblank &= ~((2 * FB_CVT_CELLSIZE) - 1);
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| 121 |
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| 122 | return hblank;
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| 123 | }
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| 124 |
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| 125 | static u32 fb_cvt_hsync(struct fb_cvt_data *cvt)
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| 126 | {
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| 127 | u32 hsync;
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| 128 |
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| 129 | if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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| 130 | hsync = 32;
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| 131 | else
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| 132 | hsync = (FB_CVT_CELLSIZE * cvt->htotal)/100;
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| 133 |
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| 134 | hsync &= ~(FB_CVT_CELLSIZE - 1);
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| 135 | return hsync;
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| 136 | }
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| 137 |
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| 138 | static u32 fb_cvt_vbi_lines(struct fb_cvt_data *cvt)
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| 139 | {
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| 140 | u32 vbi_lines, min_vbi_lines, act_vbi_lines;
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| 141 |
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| 142 | if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK) {
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| 143 | vbi_lines = (1000 * FB_CVT_RB_MIN_VBLANK)/cvt->hperiod + 1;
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| 144 | min_vbi_lines = FB_CVT_RB_V_FPORCH + cvt->vsync +
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| 145 | FB_CVT_MIN_BPORCH;
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| 146 |
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| 147 | } else {
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| 148 | vbi_lines = (FB_CVT_MIN_VSYNC_BP * 1000)/cvt->hperiod + 1 +
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| 149 | FB_CVT_MIN_VPORCH;
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| 150 | min_vbi_lines = cvt->vsync + FB_CVT_MIN_BPORCH +
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| 151 | FB_CVT_MIN_VPORCH;
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| 152 | }
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| 153 |
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| 154 | if (vbi_lines < min_vbi_lines)
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| 155 | act_vbi_lines = min_vbi_lines;
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| 156 | else
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| 157 | act_vbi_lines = vbi_lines;
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| 158 |
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| 159 | return act_vbi_lines;
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| 160 | }
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| 161 |
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| 162 | static u32 fb_cvt_vtotal(struct fb_cvt_data *cvt)
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| 163 | {
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| 164 | u32 vtotal = cvt->yres/cvt->interlace;
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| 165 |
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| 166 | vtotal += 2 * cvt->v_margin + cvt->interlace/2 + fb_cvt_vbi_lines(cvt);
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| 167 | vtotal |= cvt->interlace/2;
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| 168 |
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| 169 | return vtotal;
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| 170 | }
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| 171 |
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| 172 | static u32 fb_cvt_pixclock(struct fb_cvt_data *cvt)
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| 173 | {
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| 174 | u32 pixclock;
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| 175 |
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| 176 | if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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| 177 | pixclock = (cvt->f_refresh * cvt->vtotal * cvt->htotal)/1000;
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| 178 | else
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| 179 | pixclock = (cvt->htotal * 1000000)/cvt->hperiod;
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| 180 |
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| 181 | pixclock /= 250;
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| 182 | pixclock *= 250;
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| 183 | pixclock *= 1000;
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| 184 |
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| 185 | return pixclock;
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| 186 | }
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| 187 |
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| 188 | static u32 fb_cvt_aspect_ratio(struct fb_cvt_data *cvt)
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| 189 | {
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| 190 | u32 xres = cvt->xres;
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| 191 | u32 yres = cvt->yres;
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| 192 | u32 aspect = -1;
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| 193 |
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| 194 | if (xres == (yres * 4)/3 && !((yres * 4) % 3))
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| 195 | aspect = 0;
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| 196 | else if (xres == (yres * 16)/9 && !((yres * 16) % 9))
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| 197 | aspect = 1;
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| 198 | else if (xres == (yres * 16)/10 && !((yres * 16) % 10))
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| 199 | aspect = 2;
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| 200 | else if (xres == (yres * 5)/4 && !((yres * 5) % 4))
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| 201 | aspect = 3;
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| 202 | else if (xres == (yres * 15)/9 && !((yres * 15) % 9))
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| 203 | aspect = 4;
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| 204 | else {
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| 205 | printk(KERN_INFO "fbcvt: Aspect ratio not CVT "
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| 206 | "standard\n");
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| 207 | aspect = 7;
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| 208 | cvt->status = 1;
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| 209 | }
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| 210 |
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| 211 | return aspect;
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| 212 | }
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| 213 |
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| 214 | static void fb_cvt_print_name(struct fb_cvt_data *cvt)
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| 215 | {
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| 216 | u32 pixcount, pixcount_mod;
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| 217 | int size = 256;
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| 218 | int off = 0;
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| 219 | u8 *buf;
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| 220 |
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| 221 | buf = kzalloc(size, GFP_KERNEL);
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| 222 | if (!buf)
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| 223 | return;
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| 224 |
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| 225 | pixcount = (cvt->xres * (cvt->yres/cvt->interlace))/1000000;
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| 226 | pixcount_mod = (cvt->xres * (cvt->yres/cvt->interlace)) % 1000000;
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| 227 | pixcount_mod /= 1000;
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| 228 |
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| 229 | off += scnprintf(buf + off, size - off, "fbcvt: %dx%d@%d: CVT Name - ",
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| 230 | cvt->xres, cvt->yres, cvt->refresh);
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| 231 |
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| 232 | if (cvt->status) {
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| 233 | off += scnprintf(buf + off, size - off,
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| 234 | "Not a CVT standard - %d.%03d Mega Pixel Image\n",
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| 235 | pixcount, pixcount_mod);
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| 236 | } else {
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| 237 | if (pixcount)
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| 238 | off += scnprintf(buf + off, size - off, "%d", pixcount);
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| 239 |
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| 240 | off += scnprintf(buf + off, size - off, ".%03dM", pixcount_mod);
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| 241 |
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| 242 | if (cvt->aspect_ratio == 0)
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| 243 | off += scnprintf(buf + off, size - off, "3");
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| 244 | else if (cvt->aspect_ratio == 3)
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| 245 | off += scnprintf(buf + off, size - off, "4");
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| 246 | else if (cvt->aspect_ratio == 1 || cvt->aspect_ratio == 4)
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| 247 | off += scnprintf(buf + off, size - off, "9");
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| 248 | else if (cvt->aspect_ratio == 2)
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| 249 | off += scnprintf(buf + off, size - off, "A");
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| 250 |
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| 251 | if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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| 252 | off += scnprintf(buf + off, size - off, "-R");
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| 253 | }
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| 254 |
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| 255 | printk(KERN_INFO "%s\n", buf);
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| 256 | kfree(buf);
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| 257 | }
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| 258 |
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| 259 | static void fb_cvt_convert_to_mode(struct fb_cvt_data *cvt,
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| 260 | struct fb_videomode *mode)
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| 261 | {
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| 262 | mode->refresh = cvt->f_refresh;
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| 263 | mode->pixclock = KHZ2PICOS(cvt->pixclock/1000);
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| 264 | mode->left_margin = cvt->h_back_porch;
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| 265 | mode->right_margin = cvt->h_front_porch;
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| 266 | mode->hsync_len = cvt->hsync;
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| 267 | mode->upper_margin = cvt->v_back_porch;
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| 268 | mode->lower_margin = cvt->v_front_porch;
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| 269 | mode->vsync_len = cvt->vsync;
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| 270 |
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| 271 | mode->sync &= ~(FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT);
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| 272 |
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| 273 | if (cvt->flags & FB_CVT_FLAG_REDUCED_BLANK)
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| 274 | mode->sync |= FB_SYNC_HOR_HIGH_ACT;
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| 275 | else
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| 276 | mode->sync |= FB_SYNC_VERT_HIGH_ACT;
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| 277 | }
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| 278 |
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| 279 | |
| 280 | * fb_find_mode_cvt - calculate mode using VESA(TM) CVT
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| 281 | * @mode: pointer to fb_videomode; xres, yres, refresh and vmode must be
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| 282 | * pre-filled with the desired values
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| 283 | * @margins: add margin to calculation (1.8% of xres and yres)
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| 284 | * @rb: compute with reduced blanking (for flatpanels)
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| 285 | *
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| 286 | * RETURNS:
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| 287 | * 0 for success
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| 288 | * @mode is filled with computed values. If interlaced, the refresh field
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| 289 | * will be filled with the field rate (2x the frame rate)
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| 290 | *
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| 291 | * DESCRIPTION:
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| 292 | * Computes video timings using VESA(TM) Coordinated Video Timings
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| 293 |
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| 294 | int fb_find_mode_cvt(struct fb_videomode *mode, int margins, int rb)
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| 295 | {
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| 296 | struct fb_cvt_data cvt;
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| 297 |
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| 298 | memset(&cvt, 0, sizeof(cvt));
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| 299 |
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| 300 | if (margins)
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| 301 | cvt.flags |= FB_CVT_FLAG_MARGINS;
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| 302 |
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| 303 | if (rb)
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| 304 | cvt.flags |= FB_CVT_FLAG_REDUCED_BLANK;
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| 305 |
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| 306 | if (mode->vmode & FB_VMODE_INTERLACED)
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| 307 | cvt.flags |= FB_CVT_FLAG_INTERLACED;
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| 308 |
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| 309 | cvt.xres = mode->xres;
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| 310 | cvt.yres = mode->yres;
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| 311 | cvt.refresh = mode->refresh;
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| 312 | cvt.f_refresh = cvt.refresh;
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| 313 | cvt.interlace = 1;
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| 314 |
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| 315 | if (!cvt.xres || !cvt.yres || !cvt.refresh || cvt.f_refresh > INT_MAX) {
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| 316 | printk(KERN_INFO "fbcvt: Invalid input parameters\n");
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| 317 | return 1;
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| 318 | }
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| 319 |
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| 320 | if (!(cvt.refresh == 50 || cvt.refresh == 60 || cvt.refresh == 70 ||
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| 321 | cvt.refresh == 85)) {
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| 322 | printk(KERN_INFO "fbcvt: Refresh rate not CVT "
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| 323 | "standard\n");
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| 324 | cvt.status = 1;
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| 325 | }
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| 326 |
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| 327 | cvt.xres &= ~(FB_CVT_CELLSIZE - 1);
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| 328 |
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| 329 | if (cvt.flags & FB_CVT_FLAG_INTERLACED) {
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| 330 | cvt.interlace = 2;
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| 331 | cvt.f_refresh *= 2;
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| 332 | }
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| 333 |
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| 334 | if (cvt.flags & FB_CVT_FLAG_REDUCED_BLANK) {
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| 335 | if (cvt.refresh != 60) {
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| 336 | printk(KERN_INFO "fbcvt: 60Hz refresh rate "
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| 337 | "advised for reduced blanking\n");
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| 338 | cvt.status = 1;
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| 339 | }
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| 340 | }
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| 341 |
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| 342 | if (cvt.flags & FB_CVT_FLAG_MARGINS) {
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| 343 | cvt.h_margin = (cvt.xres * 18)/1000;
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| 344 | cvt.h_margin &= ~(FB_CVT_CELLSIZE - 1);
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| 345 | cvt.v_margin = ((cvt.yres/cvt.interlace)* 18)/1000;
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| 346 | }
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| 347 |
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| 348 | cvt.aspect_ratio = fb_cvt_aspect_ratio(&cvt);
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| 349 | cvt.active_pixels = cvt.xres + 2 * cvt.h_margin;
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| 350 | cvt.hperiod = fb_cvt_hperiod(&cvt);
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| 351 | cvt.vsync = fb_cvt_vbi_tab[cvt.aspect_ratio];
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| 352 | cvt.vtotal = fb_cvt_vtotal(&cvt);
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| 353 | cvt.hblank = fb_cvt_hblank(&cvt);
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| 354 | cvt.htotal = cvt.active_pixels + cvt.hblank;
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| 355 | cvt.hsync = fb_cvt_hsync(&cvt);
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| 356 | cvt.pixclock = fb_cvt_pixclock(&cvt);
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| 357 | cvt.hfreq = cvt.pixclock/cvt.htotal;
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| 358 | cvt.h_back_porch = cvt.hblank/2 + cvt.h_margin;
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| 359 | cvt.h_front_porch = cvt.hblank - cvt.hsync - cvt.h_back_porch +
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| 360 | 2 * cvt.h_margin;
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| 361 | cvt.v_front_porch = 3 + cvt.v_margin;
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| 362 | cvt.v_back_porch = cvt.vtotal - cvt.yres/cvt.interlace -
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| 363 | cvt.v_front_porch - cvt.vsync;
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| 364 | fb_cvt_print_name(&cvt);
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| 365 | fb_cvt_convert_to_mode(&cvt, mode);
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| 366 |
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| 367 | return 0;
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| 368 | }
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