1 /* Copied from hw/xfree86/modes/xf86cvt.c into xwayland DDX and
2 * changed to generate an RRMode */
3
4 /*
5 * Copyright 2005-2006 Luc Verhaegen.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
24 */
25
26 /*
27 * The reason for having this function in a file of its own is
28 * so that ../utils/cvt/cvt can link to it, and that xf86CVTMode
29 * code is shared directly.
30 */
31
32 #include <xwayland-config.h>
33
34 #include <string.h>
35 #include <randrstr.h>
36
37 #include "xwayland-cvt.h"
38
39 /*
40 * Generate a CVT standard mode from HDisplay, VDisplay and VRefresh.
41 *
42 * These calculations are stolen from the CVT calculation spreadsheet written
43 * by Graham Loveridge. He seems to be claiming no copyright and there seems to
44 * be no license attached to this. He apparently just wants to see his name
45 * mentioned.
46 *
47 * This file can be found at http://www.vesa.org/Public/CVT/CVTd6r1.xls
48 *
49 * Comments and structure corresponds to the comments and structure of the xls.
50 * This should ease importing of future changes to the standard (not very
51 * likely though).
52 *
53 * About margins; i'm sure that they are to be the bit between HDisplay and
54 * HBlankStart, HBlankEnd and HTotal, VDisplay and VBlankStart, VBlankEnd and
55 * VTotal, where the overscan colour is shown. FB seems to call _all_ blanking
56 * outside sync "margin" for some reason. Since we prefer seeing proper
57 * blanking instead of the overscan colour, and since the Crtc* values will
58 * probably get altered after us, we will disable margins altogether. With
59 * these calculations, Margins will plainly expand H/VDisplay, and we don't
60 * want that. -- libv
61 *
62 */
63 RRModePtr
xwayland_cvt(int HDisplay,int VDisplay,float VRefresh,Bool Reduced,Bool Interlaced)64 xwayland_cvt(int HDisplay, int VDisplay, float VRefresh, Bool Reduced,
65 Bool Interlaced)
66 {
67 /* 1) top/bottom margin size (% of height) - default: 1.8 */
68 #define CVT_MARGIN_PERCENTAGE 1.8
69
70 /* 2) character cell horizontal granularity (pixels) - default 8 */
71 #define CVT_H_GRANULARITY 8
72
73 /* 4) Minimum vertical porch (lines) - default 3 */
74 #define CVT_MIN_V_PORCH 3
75
76 /* 4) Minimum number of vertical back porch lines - default 6 */
77 #define CVT_MIN_V_BPORCH 6
78
79 /* Pixel Clock step (kHz) */
80 #define CVT_CLOCK_STEP 250
81
82 Bool Margins = FALSE;
83 float VFieldRate, HPeriod;
84 int HDisplayRnd, HMargin;
85 int VDisplayRnd, VMargin, VSync;
86 float Interlace; /* Please rename this */
87 char name[128];
88 xRRModeInfo modeinfo;
89
90 memset(&modeinfo, 0, sizeof modeinfo);
91
92 /* CVT default is 60.0Hz */
93 if (!VRefresh)
94 VRefresh = 60.0;
95
96 /* 1. Required field rate */
97 if (Interlaced)
98 VFieldRate = VRefresh * 2;
99 else
100 VFieldRate = VRefresh;
101
102 /* 2. Horizontal pixels */
103 HDisplayRnd = HDisplay - (HDisplay % CVT_H_GRANULARITY);
104
105 /* 3. Determine left and right borders */
106 if (Margins) {
107 /* right margin is actually exactly the same as left */
108 HMargin = (((float) HDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0);
109 HMargin -= HMargin % CVT_H_GRANULARITY;
110 }
111 else
112 HMargin = 0;
113
114 /* 4. Find total active pixels */
115 modeinfo.width = HDisplayRnd + 2 * HMargin;
116
117 /* 5. Find number of lines per field */
118 if (Interlaced)
119 VDisplayRnd = VDisplay / 2;
120 else
121 VDisplayRnd = VDisplay;
122
123 /* 6. Find top and bottom margins */
124 /* nope. */
125 if (Margins)
126 /* top and bottom margins are equal again. */
127 VMargin = (((float) VDisplayRnd) * CVT_MARGIN_PERCENTAGE / 100.0);
128 else
129 VMargin = 0;
130
131 modeinfo.height = VDisplay + 2 * VMargin;
132
133 /* 7. Interlace */
134 if (Interlaced)
135 Interlace = 0.5;
136 else
137 Interlace = 0.0;
138
139 /* Determine VSync Width from aspect ratio */
140 if (!(VDisplay % 3) && ((VDisplay * 4 / 3) == HDisplay))
141 VSync = 4;
142 else if (!(VDisplay % 9) && ((VDisplay * 16 / 9) == HDisplay))
143 VSync = 5;
144 else if (!(VDisplay % 10) && ((VDisplay * 16 / 10) == HDisplay))
145 VSync = 6;
146 else if (!(VDisplay % 4) && ((VDisplay * 5 / 4) == HDisplay))
147 VSync = 7;
148 else if (!(VDisplay % 9) && ((VDisplay * 15 / 9) == HDisplay))
149 VSync = 7;
150 else /* Custom */
151 VSync = 10;
152
153 if (!Reduced) { /* simplified GTF calculation */
154
155 /* 4) Minimum time of vertical sync + back porch interval (µs)
156 * default 550.0 */
157 #define CVT_MIN_VSYNC_BP 550.0
158
159 /* 3) Nominal HSync width (% of line period) - default 8 */
160 #define CVT_HSYNC_PERCENTAGE 8
161
162 float HBlankPercentage;
163 int VSyncAndBackPorch, VBackPorch;
164 int HBlank;
165
166 /* 8. Estimated Horizontal period */
167 HPeriod = ((float) (1000000.0 / VFieldRate - CVT_MIN_VSYNC_BP)) /
168 (VDisplayRnd + 2 * VMargin + CVT_MIN_V_PORCH + Interlace);
169
170 /* 9. Find number of lines in sync + backporch */
171 if (((int) (CVT_MIN_VSYNC_BP / HPeriod) + 1) <
172 (VSync + CVT_MIN_V_PORCH))
173 VSyncAndBackPorch = VSync + CVT_MIN_V_PORCH;
174 else
175 VSyncAndBackPorch = (int) (CVT_MIN_VSYNC_BP / HPeriod) + 1;
176
177 /* 10. Find number of lines in back porch */
178 VBackPorch = VSyncAndBackPorch - VSync;
179 (void) VBackPorch;
180
181 /* 11. Find total number of lines in vertical field */
182 modeinfo.vTotal =
183 VDisplayRnd + 2 * VMargin + VSyncAndBackPorch + Interlace +
184 CVT_MIN_V_PORCH;
185
186 /* 5) Definition of Horizontal blanking time limitation */
187 /* Gradient (%/kHz) - default 600 */
188 #define CVT_M_FACTOR 600
189
190 /* Offset (%) - default 40 */
191 #define CVT_C_FACTOR 40
192
193 /* Blanking time scaling factor - default 128 */
194 #define CVT_K_FACTOR 128
195
196 /* Scaling factor weighting - default 20 */
197 #define CVT_J_FACTOR 20
198
199 #define CVT_M_PRIME CVT_M_FACTOR * CVT_K_FACTOR / 256
200 #define CVT_C_PRIME (CVT_C_FACTOR - CVT_J_FACTOR) * CVT_K_FACTOR / 256 + \
201 CVT_J_FACTOR
202
203 /* 12. Find ideal blanking duty cycle from formula */
204 HBlankPercentage = CVT_C_PRIME - CVT_M_PRIME * HPeriod / 1000.0;
205
206 /* 13. Blanking time */
207 if (HBlankPercentage < 20)
208 HBlankPercentage = 20;
209
210 HBlank = modeinfo.width * HBlankPercentage / (100.0 - HBlankPercentage);
211 HBlank -= HBlank % (2 * CVT_H_GRANULARITY);
212
213 /* 14. Find total number of pixels in a line. */
214 modeinfo.hTotal = modeinfo.width + HBlank;
215
216 /* Fill in HSync values */
217 modeinfo.hSyncEnd = modeinfo.width + HBlank / 2;
218
219 modeinfo.hSyncStart = modeinfo.hSyncEnd -
220 (modeinfo.hTotal * CVT_HSYNC_PERCENTAGE) / 100;
221 modeinfo.hSyncStart += CVT_H_GRANULARITY -
222 modeinfo.hSyncStart % CVT_H_GRANULARITY;
223
224 /* Fill in VSync values */
225 modeinfo.vSyncStart = modeinfo.height + CVT_MIN_V_PORCH;
226 modeinfo.vSyncEnd = modeinfo.vSyncStart + VSync;
227
228 }
229 else { /* Reduced blanking */
230 /* Minimum vertical blanking interval time (µs) - default 460 */
231 #define CVT_RB_MIN_VBLANK 460.0
232
233 /* Fixed number of clocks for horizontal sync */
234 #define CVT_RB_H_SYNC 32.0
235
236 /* Fixed number of clocks for horizontal blanking */
237 #define CVT_RB_H_BLANK 160.0
238
239 /* Fixed number of lines for vertical front porch - default 3 */
240 #define CVT_RB_VFPORCH 3
241
242 int VBILines;
243
244 /* 8. Estimate Horizontal period. */
245 HPeriod = ((float) (1000000.0 / VFieldRate - CVT_RB_MIN_VBLANK)) /
246 (VDisplayRnd + 2 * VMargin);
247
248 /* 9. Find number of lines in vertical blanking */
249 VBILines = ((float) CVT_RB_MIN_VBLANK) / HPeriod + 1;
250
251 /* 10. Check if vertical blanking is sufficient */
252 if (VBILines < (CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH))
253 VBILines = CVT_RB_VFPORCH + VSync + CVT_MIN_V_BPORCH;
254
255 /* 11. Find total number of lines in vertical field */
256 modeinfo.vTotal = VDisplayRnd + 2 * VMargin + Interlace + VBILines;
257
258 /* 12. Find total number of pixels in a line */
259 modeinfo.hTotal = modeinfo.width + CVT_RB_H_BLANK;
260
261 /* Fill in HSync values */
262 modeinfo.hSyncEnd = modeinfo.width + CVT_RB_H_BLANK / 2;
263 modeinfo.hSyncStart = modeinfo.hSyncEnd - CVT_RB_H_SYNC;
264
265 /* Fill in VSync values */
266 modeinfo.vSyncStart = modeinfo.height + CVT_RB_VFPORCH;
267 modeinfo.vSyncEnd = modeinfo.vSyncStart + VSync;
268 }
269
270 /* 15/13. Find pixel clock frequency (kHz for xf86) */
271 modeinfo.dotClock = modeinfo.hTotal * 1000.0 / HPeriod;
272 modeinfo.dotClock -= modeinfo.dotClock % CVT_CLOCK_STEP;
273 modeinfo.dotClock *= 1000.0;
274 #if 0
275 /* 16/14. Find actual Horizontal Frequency (kHz) */
276 modeinfo.hSync = ((float) modeinfo.dotClock) / ((float) modeinfo.hTotal);
277 #endif
278
279 #if 0
280 /* 17/15. Find actual Field rate */
281 modeinfo.vRefresh = (1000.0 * ((float) modeinfo.dotClock)) /
282 ((float) (modeinfo.hTotal * modeinfo.vTotal));
283 #endif
284
285 /* 18/16. Find actual vertical frame frequency */
286 /* ignore - just set the mode flag for interlaced */
287 if (Interlaced)
288 modeinfo.vTotal *= 2;
289
290 if (Reduced)
291 modeinfo.modeFlags |= RR_HSyncPositive | RR_VSyncNegative;
292 else
293 modeinfo.modeFlags |= RR_HSyncNegative | RR_VSyncPositive;
294
295 if (Interlaced)
296 modeinfo.modeFlags |= RR_Interlace;
297
298 /* FWXGA hack adapted from hw/xfree86/modes/xf86EdidModes.c, because you can't say 1366 */
299 if (HDisplay == 1366 && VDisplay == 768) {
300 modeinfo.width = 1366;
301 modeinfo.hSyncStart--;
302 modeinfo.hSyncEnd--;
303 }
304
305 snprintf(name, sizeof name, "%dx%d",
306 modeinfo.width, modeinfo.height);
307 modeinfo.nameLength = strlen(name);
308
309 return RRModeGet(&modeinfo, name);
310 }
311