2 * linux/drivers/video/fbmon.c
4 * Copyright (C) 2002 James Simmons <jsimmons@users.sf.net>
8 * The EDID Parser is a conglomeration from the following sources:
10 * 1. SciTech SNAP Graphics Architecture
11 * Copyright (C) 1991-2002 SciTech Software, Inc. All rights reserved.
13 * 2. XFree86 4.3.0, interpret_edid.c
14 * Copyright 1998 by Egbert Eich <Egbert.Eich@Physik.TU-Darmstadt.DE>
16 * 3. John Fremlin <vii@users.sourceforge.net> and
17 * Ani Joshi <ajoshi@unixbox.com>
19 * Generalized Timing Formula is derived from:
21 * GTF Spreadsheet by Andy Morrish (1/5/97)
22 * available at http://www.vesa.org
24 * This file is subject to the terms and conditions of the GNU General Public
25 * License. See the file COPYING in the main directory of this archive
29 #include <linux/tty.h>
31 #include <linux/module.h>
33 #include <linux/pci.h>
35 #include <asm/pci-bridge.h>
37 #include <video/edid.h>
44 #undef DEBUG /* define this for verbose EDID parsing output */
47 #define DPRINTK(fmt, args...) printk(fmt,## args)
49 #define DPRINTK(fmt, args...)
52 #define FBMON_FIX_HEADER 1
53 #define FBMON_FIX_INPUT 2
55 #ifdef CONFIG_FB_MODE_HELPERS
62 static struct broken_edid brokendb[] = {
65 .manufacturer = "DEC",
67 .fix = FBMON_FIX_HEADER,
69 /* ViewSonic PF775a */
71 .manufacturer = "VSC",
73 .fix = FBMON_FIX_INPUT,
77 static const unsigned char edid_v1_header[] = { 0x00, 0xff, 0xff, 0xff,
78 0xff, 0xff, 0xff, 0x00
81 static void copy_string(unsigned char *c, unsigned char *s)
85 for (i = 0; (i < 13 && *c != 0x0A); i++)
88 while (i-- && (*--s == 0x20)) *s = 0;
91 static int check_edid(unsigned char *edid)
93 unsigned char *block = edid + ID_MANUFACTURER_NAME, manufacturer[4];
96 int i, fix = 0, ret = 0;
98 manufacturer[0] = ((block[0] & 0x7c) >> 2) + '@';
99 manufacturer[1] = ((block[0] & 0x03) << 3) +
100 ((block[1] & 0xe0) >> 5) + '@';
101 manufacturer[2] = (block[1] & 0x1f) + '@';
103 model = block[2] + (block[3] << 8);
105 for (i = 0; i < ARRAY_SIZE(brokendb); i++) {
106 if (!strncmp(manufacturer, brokendb[i].manufacturer, 4) &&
107 brokendb[i].model == model) {
108 printk("fbmon: The EDID Block of "
109 "Manufacturer: %s Model: 0x%x is known to "
110 "be broken,\n", manufacturer, model);
111 fix = brokendb[i].fix;
117 case FBMON_FIX_HEADER:
118 for (i = 0; i < 8; i++) {
119 if (edid[i] != edid_v1_header[i])
123 case FBMON_FIX_INPUT:
124 b = edid + EDID_STRUCT_DISPLAY;
125 /* Only if display is GTF capable will
126 the input type be reset to analog */
127 if (b[4] & 0x01 && b[0] & 0x80)
135 static void fix_edid(unsigned char *edid, int fix)
140 case FBMON_FIX_HEADER:
141 printk("fbmon: trying a header reconstruct\n");
142 memcpy(edid, edid_v1_header, 8);
144 case FBMON_FIX_INPUT:
145 printk("fbmon: trying to fix input type\n");
146 b = edid + EDID_STRUCT_DISPLAY;
152 static int edid_checksum(unsigned char *edid)
154 unsigned char i, csum = 0, all_null = 0;
155 int err = 0, fix = check_edid(edid);
160 for (i = 0; i < EDID_LENGTH; i++) {
165 if (csum == 0x00 && all_null) {
166 /* checksum passed, everything's good */
173 static int edid_check_header(unsigned char *edid)
175 int i, err = 1, fix = check_edid(edid);
180 for (i = 0; i < 8; i++) {
181 if (edid[i] != edid_v1_header[i])
188 static void parse_vendor_block(unsigned char *block, struct fb_monspecs *specs)
190 specs->manufacturer[0] = ((block[0] & 0x7c) >> 2) + '@';
191 specs->manufacturer[1] = ((block[0] & 0x03) << 3) +
192 ((block[1] & 0xe0) >> 5) + '@';
193 specs->manufacturer[2] = (block[1] & 0x1f) + '@';
194 specs->manufacturer[3] = 0;
195 specs->model = block[2] + (block[3] << 8);
196 specs->serial = block[4] + (block[5] << 8) +
197 (block[6] << 16) + (block[7] << 24);
198 specs->year = block[9] + 1990;
199 specs->week = block[8];
200 DPRINTK(" Manufacturer: %s\n", specs->manufacturer);
201 DPRINTK(" Model: %x\n", specs->model);
202 DPRINTK(" Serial#: %u\n", specs->serial);
203 DPRINTK(" Year: %u Week %u\n", specs->year, specs->week);
206 static void get_dpms_capabilities(unsigned char flags,
207 struct fb_monspecs *specs)
210 if (flags & DPMS_ACTIVE_OFF)
211 specs->dpms |= FB_DPMS_ACTIVE_OFF;
212 if (flags & DPMS_SUSPEND)
213 specs->dpms |= FB_DPMS_SUSPEND;
214 if (flags & DPMS_STANDBY)
215 specs->dpms |= FB_DPMS_STANDBY;
216 DPRINTK(" DPMS: Active %s, Suspend %s, Standby %s\n",
217 (flags & DPMS_ACTIVE_OFF) ? "yes" : "no",
218 (flags & DPMS_SUSPEND) ? "yes" : "no",
219 (flags & DPMS_STANDBY) ? "yes" : "no");
222 static void get_chroma(unsigned char *block, struct fb_monspecs *specs)
226 DPRINTK(" Chroma\n");
227 /* Chromaticity data */
228 tmp = ((block[5] & (3 << 6)) >> 6) | (block[0x7] << 2);
231 specs->chroma.redx = tmp/1024;
232 DPRINTK(" RedX: 0.%03d ", specs->chroma.redx);
234 tmp = ((block[5] & (3 << 4)) >> 4) | (block[0x8] << 2);
237 specs->chroma.redy = tmp/1024;
238 DPRINTK("RedY: 0.%03d\n", specs->chroma.redy);
240 tmp = ((block[5] & (3 << 2)) >> 2) | (block[0x9] << 2);
243 specs->chroma.greenx = tmp/1024;
244 DPRINTK(" GreenX: 0.%03d ", specs->chroma.greenx);
246 tmp = (block[5] & 3) | (block[0xa] << 2);
249 specs->chroma.greeny = tmp/1024;
250 DPRINTK("GreenY: 0.%03d\n", specs->chroma.greeny);
252 tmp = ((block[6] & (3 << 6)) >> 6) | (block[0xb] << 2);
255 specs->chroma.bluex = tmp/1024;
256 DPRINTK(" BlueX: 0.%03d ", specs->chroma.bluex);
258 tmp = ((block[6] & (3 << 4)) >> 4) | (block[0xc] << 2);
261 specs->chroma.bluey = tmp/1024;
262 DPRINTK("BlueY: 0.%03d\n", specs->chroma.bluey);
264 tmp = ((block[6] & (3 << 2)) >> 2) | (block[0xd] << 2);
267 specs->chroma.whitex = tmp/1024;
268 DPRINTK(" WhiteX: 0.%03d ", specs->chroma.whitex);
270 tmp = (block[6] & 3) | (block[0xe] << 2);
273 specs->chroma.whitey = tmp/1024;
274 DPRINTK("WhiteY: 0.%03d\n", specs->chroma.whitey);
277 static int edid_is_serial_block(unsigned char *block)
279 if ((block[0] == 0x00) && (block[1] == 0x00) &&
280 (block[2] == 0x00) && (block[3] == 0xff) &&
287 static int edid_is_ascii_block(unsigned char *block)
289 if ((block[0] == 0x00) && (block[1] == 0x00) &&
290 (block[2] == 0x00) && (block[3] == 0xfe) &&
297 static int edid_is_limits_block(unsigned char *block)
299 if ((block[0] == 0x00) && (block[1] == 0x00) &&
300 (block[2] == 0x00) && (block[3] == 0xfd) &&
307 static int edid_is_monitor_block(unsigned char *block)
309 if ((block[0] == 0x00) && (block[1] == 0x00) &&
310 (block[2] == 0x00) && (block[3] == 0xfc) &&
317 static void calc_mode_timings(int xres, int yres, int refresh, struct fb_videomode *mode)
319 struct fb_var_screeninfo var;
324 fb_get_mode(FB_VSYNCTIMINGS | FB_IGNOREMON,
325 refresh, &var, &info);
328 mode->pixclock = var.pixclock;
329 mode->refresh = refresh;
330 mode->left_margin = var.left_margin;
331 mode->right_margin = var.right_margin;
332 mode->upper_margin = var.upper_margin;
333 mode->lower_margin = var.lower_margin;
334 mode->hsync_len = var.hsync_len;
335 mode->vsync_len = var.vsync_len;
340 static int get_est_timing(unsigned char *block, struct fb_videomode *mode)
347 calc_mode_timings(720, 400, 70, &mode[num]);
348 mode[num++].flag = FB_MODE_IS_CALCULATED;
349 DPRINTK(" 720x400@70Hz\n");
352 calc_mode_timings(720, 400, 88, &mode[num]);
353 mode[num++].flag = FB_MODE_IS_CALCULATED;
354 DPRINTK(" 720x400@88Hz\n");
357 mode[num++] = vesa_modes[3];
358 DPRINTK(" 640x480@60Hz\n");
361 calc_mode_timings(640, 480, 67, &mode[num]);
362 mode[num++].flag = FB_MODE_IS_CALCULATED;
363 DPRINTK(" 640x480@67Hz\n");
366 mode[num++] = vesa_modes[4];
367 DPRINTK(" 640x480@72Hz\n");
370 mode[num++] = vesa_modes[5];
371 DPRINTK(" 640x480@75Hz\n");
374 mode[num++] = vesa_modes[7];
375 DPRINTK(" 800x600@56Hz\n");
378 mode[num++] = vesa_modes[8];
379 DPRINTK(" 800x600@60Hz\n");
384 mode[num++] = vesa_modes[9];
385 DPRINTK(" 800x600@72Hz\n");
388 mode[num++] = vesa_modes[10];
389 DPRINTK(" 800x600@75Hz\n");
392 calc_mode_timings(832, 624, 75, &mode[num]);
393 mode[num++].flag = FB_MODE_IS_CALCULATED;
394 DPRINTK(" 832x624@75Hz\n");
397 mode[num++] = vesa_modes[12];
398 DPRINTK(" 1024x768@87Hz Interlaced\n");
401 mode[num++] = vesa_modes[13];
402 DPRINTK(" 1024x768@60Hz\n");
405 mode[num++] = vesa_modes[14];
406 DPRINTK(" 1024x768@70Hz\n");
409 mode[num++] = vesa_modes[15];
410 DPRINTK(" 1024x768@75Hz\n");
413 mode[num++] = vesa_modes[21];
414 DPRINTK(" 1280x1024@75Hz\n");
418 mode[num++] = vesa_modes[17];
419 DPRINTK(" 1152x870@75Hz\n");
421 DPRINTK(" Manufacturer's mask: %x\n",c&0x7F);
425 static int get_std_timing(unsigned char *block, struct fb_videomode *mode)
427 int xres, yres = 0, refresh, ratio, i;
429 xres = (block[0] + 31) * 8;
433 ratio = (block[1] & 0xc0) >> 6;
445 yres = (xres * 9)/16;
448 refresh = (block[1] & 0x3f) + 60;
450 DPRINTK(" %dx%d@%dHz\n", xres, yres, refresh);
451 for (i = 0; i < VESA_MODEDB_SIZE; i++) {
452 if (vesa_modes[i].xres == xres &&
453 vesa_modes[i].yres == yres &&
454 vesa_modes[i].refresh == refresh) {
455 *mode = vesa_modes[i];
456 mode->flag |= FB_MODE_IS_STANDARD;
460 calc_mode_timings(xres, yres, refresh, mode);
464 static int get_dst_timing(unsigned char *block,
465 struct fb_videomode *mode)
469 for (j = 0; j < 6; j++, block+= STD_TIMING_DESCRIPTION_SIZE)
470 num += get_std_timing(block, &mode[num]);
475 static void get_detailed_timing(unsigned char *block,
476 struct fb_videomode *mode)
478 mode->xres = H_ACTIVE;
479 mode->yres = V_ACTIVE;
480 mode->pixclock = PIXEL_CLOCK;
481 mode->pixclock /= 1000;
482 mode->pixclock = KHZ2PICOS(mode->pixclock);
483 mode->right_margin = H_SYNC_OFFSET;
484 mode->left_margin = (H_ACTIVE + H_BLANKING) -
485 (H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH);
486 mode->upper_margin = V_BLANKING - V_SYNC_OFFSET -
488 mode->lower_margin = V_SYNC_OFFSET;
489 mode->hsync_len = H_SYNC_WIDTH;
490 mode->vsync_len = V_SYNC_WIDTH;
492 mode->sync |= FB_SYNC_HOR_HIGH_ACT;
494 mode->sync |= FB_SYNC_VERT_HIGH_ACT;
495 mode->refresh = PIXEL_CLOCK/((H_ACTIVE + H_BLANKING) *
496 (V_ACTIVE + V_BLANKING));
498 mode->flag = FB_MODE_IS_DETAILED;
500 DPRINTK(" %d MHz ", PIXEL_CLOCK/1000000);
501 DPRINTK("%d %d %d %d ", H_ACTIVE, H_ACTIVE + H_SYNC_OFFSET,
502 H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH, H_ACTIVE + H_BLANKING);
503 DPRINTK("%d %d %d %d ", V_ACTIVE, V_ACTIVE + V_SYNC_OFFSET,
504 V_ACTIVE + V_SYNC_OFFSET + V_SYNC_WIDTH, V_ACTIVE + V_BLANKING);
505 DPRINTK("%sHSync %sVSync\n\n", (HSYNC_POSITIVE) ? "+" : "-",
506 (VSYNC_POSITIVE) ? "+" : "-");
510 * fb_create_modedb - create video mode database
512 * @dbsize: database size
514 * RETURNS: struct fb_videomode, @dbsize contains length of database
517 * This function builds a mode database using the contents of the EDID
520 static struct fb_videomode *fb_create_modedb(unsigned char *edid, int *dbsize)
522 struct fb_videomode *mode, *m;
523 unsigned char *block;
526 mode = kmalloc(50 * sizeof(struct fb_videomode), GFP_KERNEL);
529 memset(mode, 0, 50 * sizeof(struct fb_videomode));
531 if (edid == NULL || !edid_checksum(edid) ||
532 !edid_check_header(edid)) {
539 DPRINTK(" Supported VESA Modes\n");
540 block = edid + ESTABLISHED_TIMING_1;
541 num += get_est_timing(block, &mode[num]);
543 DPRINTK(" Standard Timings\n");
544 block = edid + STD_TIMING_DESCRIPTIONS_START;
545 for (i = 0; i < STD_TIMING; i++, block += STD_TIMING_DESCRIPTION_SIZE)
546 num += get_std_timing(block, &mode[num]);
548 DPRINTK(" Detailed Timings\n");
549 block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
550 for (i = 0; i < 4; i++, block+= DETAILED_TIMING_DESCRIPTION_SIZE) {
553 if (block[0] == 0x00 && block[1] == 0x00) {
554 if (block[3] == 0xfa) {
555 num += get_dst_timing(block + 5, &mode[num]);
558 get_detailed_timing(block, &mode[num]);
560 mode[num].flag |= FB_MODE_IS_FIRST;
567 /* Yikes, EDID data is totally useless */
574 m = kmalloc(num * sizeof(struct fb_videomode), GFP_KERNEL);
577 memmove(m, mode, num * sizeof(struct fb_videomode));
583 * fb_destroy_modedb - destroys mode database
584 * @modedb: mode database to destroy
587 * Destroy mode database created by fb_create_modedb
589 void fb_destroy_modedb(struct fb_videomode *modedb)
594 static int fb_get_monitor_limits(unsigned char *edid, struct fb_monspecs *specs)
597 unsigned char *block;
599 block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
601 DPRINTK(" Monitor Operating Limits: ");
602 for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
603 if (edid_is_limits_block(block)) {
604 specs->hfmin = H_MIN_RATE * 1000;
605 specs->hfmax = H_MAX_RATE * 1000;
606 specs->vfmin = V_MIN_RATE;
607 specs->vfmax = V_MAX_RATE;
608 specs->dclkmax = MAX_PIXEL_CLOCK * 1000000;
609 specs->gtf = (GTF_SUPPORT) ? 1 : 0;
611 DPRINTK("From EDID\n");
616 /* estimate monitor limits based on modes supported */
618 struct fb_videomode *modes;
619 int num_modes, i, hz, hscan, pixclock;
621 modes = fb_create_modedb(edid, &num_modes);
623 DPRINTK("None Available\n");
628 for (i = 0; i < num_modes; i++) {
629 hz = modes[i].refresh;
630 pixclock = PICOS2KHZ(modes[i].pixclock) * 1000;
631 hscan = (modes[i].yres * 105 * hz + 5000)/100;
633 if (specs->dclkmax == 0 || specs->dclkmax < pixclock)
634 specs->dclkmax = pixclock;
635 if (specs->dclkmin == 0 || specs->dclkmin > pixclock)
636 specs->dclkmin = pixclock;
637 if (specs->hfmax == 0 || specs->hfmax < hscan)
638 specs->hfmax = hscan;
639 if (specs->hfmin == 0 || specs->hfmin > hscan)
640 specs->hfmin = hscan;
641 if (specs->vfmax == 0 || specs->vfmax < hz)
643 if (specs->vfmin == 0 || specs->vfmin > hz)
646 DPRINTK("Extrapolated\n");
647 fb_destroy_modedb(modes);
649 DPRINTK(" H: %d-%dKHz V: %d-%dHz DCLK: %dMHz\n",
650 specs->hfmin/1000, specs->hfmax/1000, specs->vfmin,
651 specs->vfmax, specs->dclkmax/1000000);
655 static void get_monspecs(unsigned char *edid, struct fb_monspecs *specs)
657 unsigned char c, *block;
659 block = edid + EDID_STRUCT_DISPLAY;
661 fb_get_monitor_limits(edid, specs);
666 specs->input |= FB_DISP_DDI;
667 DPRINTK(" Digital Display Input");
669 DPRINTK(" Analog Display Input: Input Voltage - ");
670 switch ((block[0] & 0x60) >> 5) {
672 DPRINTK("0.700V/0.300V");
673 specs->input |= FB_DISP_ANA_700_300;
676 DPRINTK("0.714V/0.286V");
677 specs->input |= FB_DISP_ANA_714_286;
680 DPRINTK("1.000V/0.400V");
681 specs->input |= FB_DISP_ANA_1000_400;
684 DPRINTK("0.700V/0.000V");
685 specs->input |= FB_DISP_ANA_700_000;
689 DPRINTK("\n Sync: ");
692 DPRINTK(" Configurable signal level\n");
696 DPRINTK("Blank to Blank ");
697 specs->signal |= FB_SIGNAL_BLANK_BLANK;
700 DPRINTK("Separate ");
701 specs->signal |= FB_SIGNAL_SEPARATE;
704 DPRINTK("Composite ");
705 specs->signal |= FB_SIGNAL_COMPOSITE;
708 DPRINTK("Sync on Green ");
709 specs->signal |= FB_SIGNAL_SYNC_ON_GREEN;
712 DPRINTK("Serration on ");
713 specs->signal |= FB_SIGNAL_SERRATION_ON;
716 specs->max_x = block[1];
717 specs->max_y = block[2];
718 DPRINTK(" Max H-size in cm: ");
720 DPRINTK("%d\n", specs->max_x);
722 DPRINTK("variable\n");
723 DPRINTK(" Max V-size in cm: ");
725 DPRINTK("%d\n", specs->max_y);
727 DPRINTK("variable\n");
730 specs->gamma = c+100;
732 DPRINTK("%d.%d\n", specs->gamma/100, specs->gamma % 100);
734 get_dpms_capabilities(block[4], specs);
736 switch ((block[4] & 0x18) >> 3) {
738 DPRINTK(" Monochrome/Grayscale\n");
739 specs->input |= FB_DISP_MONO;
742 DPRINTK(" RGB Color Display\n");
743 specs->input |= FB_DISP_RGB;
746 DPRINTK(" Non-RGB Multicolor Display\n");
747 specs->input |= FB_DISP_MULTI;
750 DPRINTK(" Unknown\n");
751 specs->input |= FB_DISP_UNKNOWN;
755 get_chroma(block, specs);
760 DPRINTK(" Default color format is primary\n");
761 specs->misc |= FB_MISC_PRIM_COLOR;
764 DPRINTK(" First DETAILED Timing is preferred\n");
765 specs->misc |= FB_MISC_1ST_DETAIL;
768 printk(" Display is GTF capable\n");
773 static int edid_is_timing_block(unsigned char *block)
775 if ((block[0] != 0x00) || (block[1] != 0x00) ||
776 (block[2] != 0x00) || (block[4] != 0x00))
782 int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
785 unsigned char *block;
787 if (edid == NULL || var == NULL)
790 if (!(edid_checksum(edid)))
793 if (!(edid_check_header(edid)))
796 block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
798 for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
799 if (edid_is_timing_block(block)) {
800 var->xres = var->xres_virtual = H_ACTIVE;
801 var->yres = var->yres_virtual = V_ACTIVE;
802 var->height = var->width = -1;
803 var->right_margin = H_SYNC_OFFSET;
804 var->left_margin = (H_ACTIVE + H_BLANKING) -
805 (H_ACTIVE + H_SYNC_OFFSET + H_SYNC_WIDTH);
806 var->upper_margin = V_BLANKING - V_SYNC_OFFSET -
808 var->lower_margin = V_SYNC_OFFSET;
809 var->hsync_len = H_SYNC_WIDTH;
810 var->vsync_len = V_SYNC_WIDTH;
811 var->pixclock = PIXEL_CLOCK;
812 var->pixclock /= 1000;
813 var->pixclock = KHZ2PICOS(var->pixclock);
816 var->sync |= FB_SYNC_HOR_HIGH_ACT;
818 var->sync |= FB_SYNC_VERT_HIGH_ACT;
825 void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
827 unsigned char *block;
833 if (!(edid_checksum(edid)))
836 if (!(edid_check_header(edid)))
839 memset(specs, 0, sizeof(struct fb_monspecs));
841 specs->version = edid[EDID_STRUCT_VERSION];
842 specs->revision = edid[EDID_STRUCT_REVISION];
844 DPRINTK("========================================\n");
845 DPRINTK("Display Information (EDID)\n");
846 DPRINTK("========================================\n");
847 DPRINTK(" EDID Version %d.%d\n", (int) specs->version,
848 (int) specs->revision);
850 parse_vendor_block(edid + ID_MANUFACTURER_NAME, specs);
852 block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
853 for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
854 if (edid_is_serial_block(block)) {
855 copy_string(block, specs->serial_no);
856 DPRINTK(" Serial Number: %s\n", specs->serial_no);
857 } else if (edid_is_ascii_block(block)) {
858 copy_string(block, specs->ascii);
859 DPRINTK(" ASCII Block: %s\n", specs->ascii);
860 } else if (edid_is_monitor_block(block)) {
861 copy_string(block, specs->monitor);
862 DPRINTK(" Monitor Name: %s\n", specs->monitor);
866 DPRINTK(" Display Characteristics:\n");
867 get_monspecs(edid, specs);
869 specs->modedb = fb_create_modedb(edid, &specs->modedb_len);
870 DPRINTK("========================================\n");
874 * VESA Generalized Timing Formula (GTF)
878 #define V_FRONTPORCH 1
880 #define H_SCALEFACTOR 20
881 #define H_BLANKSCALE 128
882 #define H_GRADIENT 600
886 struct __fb_timings {
899 * fb_get_vblank - get vertical blank time
900 * @hfreq: horizontal freq
903 * vblank = right_margin + vsync_len + left_margin
905 * given: right_margin = 1 (V_FRONTPORCH)
910 * left_margin = --------------- - vsync_len
913 static u32 fb_get_vblank(u32 hfreq)
917 vblank = (hfreq * FLYBACK)/1000;
918 vblank = (vblank + 500)/1000;
919 return (vblank + V_FRONTPORCH);
923 * fb_get_hblank_by_freq - get horizontal blank time given hfreq
924 * @hfreq: horizontal freq
925 * @xres: horizontal resolution in pixels
930 * hblank = ------------------
933 * duty cycle = percent of htotal assigned to inactive display
934 * duty cycle = C - (M/Hfreq)
936 * where: C = ((offset - scale factor) * blank_scale)
937 * -------------------------------------- + scale factor
939 * M = blank_scale * gradient
942 static u32 fb_get_hblank_by_hfreq(u32 hfreq, u32 xres)
944 u32 c_val, m_val, duty_cycle, hblank;
946 c_val = (((H_OFFSET - H_SCALEFACTOR) * H_BLANKSCALE)/256 +
947 H_SCALEFACTOR) * 1000;
948 m_val = (H_BLANKSCALE * H_GRADIENT)/256;
949 m_val = (m_val * 1000000)/hfreq;
950 duty_cycle = c_val - m_val;
951 hblank = (xres * duty_cycle)/(100000 - duty_cycle);
956 * fb_get_hblank_by_dclk - get horizontal blank time given pixelclock
957 * @dclk: pixelclock in Hz
958 * @xres: horizontal resolution in pixels
963 * hblank = ------------------
966 * duty cycle = percent of htotal assigned to inactive display
967 * duty cycle = C - (M * h_period)
969 * where: h_period = SQRT(100 - C + (0.4 * xres * M)/dclk) + C - 100
970 * -----------------------------------------------
976 static u32 fb_get_hblank_by_dclk(u32 dclk, u32 xres)
978 u32 duty_cycle, h_period, hblank;
981 h_period = 100 - C_VAL;
982 h_period *= h_period;
983 h_period += (M_VAL * xres * 2 * 1000)/(5 * dclk);
986 h_period = int_sqrt(h_period);
987 h_period -= (100 - C_VAL) * 100;
989 h_period /= 2 * M_VAL;
991 duty_cycle = C_VAL * 1000 - (M_VAL * h_period)/100;
992 hblank = (xres * duty_cycle)/(100000 - duty_cycle) + 8;
998 * fb_get_hfreq - estimate hsync
999 * @vfreq: vertical refresh rate
1000 * @yres: vertical resolution
1004 * (yres + front_port) * vfreq * 1000000
1005 * hfreq = -------------------------------------
1006 * (1000000 - (vfreq * FLYBACK)
1010 static u32 fb_get_hfreq(u32 vfreq, u32 yres)
1014 divisor = (1000000 - (vfreq * FLYBACK))/1000;
1015 hfreq = (yres + V_FRONTPORCH) * vfreq * 1000;
1016 return (hfreq/divisor);
1019 static void fb_timings_vfreq(struct __fb_timings *timings)
1021 timings->hfreq = fb_get_hfreq(timings->vfreq, timings->vactive);
1022 timings->vblank = fb_get_vblank(timings->hfreq);
1023 timings->vtotal = timings->vactive + timings->vblank;
1024 timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq,
1026 timings->htotal = timings->hactive + timings->hblank;
1027 timings->dclk = timings->htotal * timings->hfreq;
1030 static void fb_timings_hfreq(struct __fb_timings *timings)
1032 timings->vblank = fb_get_vblank(timings->hfreq);
1033 timings->vtotal = timings->vactive + timings->vblank;
1034 timings->vfreq = timings->hfreq/timings->vtotal;
1035 timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq,
1037 timings->htotal = timings->hactive + timings->hblank;
1038 timings->dclk = timings->htotal * timings->hfreq;
1041 static void fb_timings_dclk(struct __fb_timings *timings)
1043 timings->hblank = fb_get_hblank_by_dclk(timings->dclk,
1045 timings->htotal = timings->hactive + timings->hblank;
1046 timings->hfreq = timings->dclk/timings->htotal;
1047 timings->vblank = fb_get_vblank(timings->hfreq);
1048 timings->vtotal = timings->vactive + timings->vblank;
1049 timings->vfreq = timings->hfreq/timings->vtotal;
1053 * fb_get_mode - calculates video mode using VESA GTF
1054 * @flags: if: 0 - maximize vertical refresh rate
1055 * 1 - vrefresh-driven calculation;
1056 * 2 - hscan-driven calculation;
1057 * 3 - pixelclock-driven calculation;
1058 * @val: depending on @flags, ignored, vrefresh, hsync or pixelclock
1059 * @var: pointer to fb_var_screeninfo
1060 * @info: pointer to fb_info
1063 * Calculates video mode based on monitor specs using VESA GTF.
1064 * The GTF is best for VESA GTF compliant monitors but is
1065 * specifically formulated to work for older monitors as well.
1067 * If @flag==0, the function will attempt to maximize the
1068 * refresh rate. Otherwise, it will calculate timings based on
1069 * the flag and accompanying value.
1071 * If FB_IGNOREMON bit is set in @flags, monitor specs will be
1072 * ignored and @var will be filled with the calculated timings.
1074 * All calculations are based on the VESA GTF Spreadsheet
1075 * available at VESA's public ftp (http://www.vesa.org).
1078 * The timings generated by the GTF will be different from VESA
1079 * DMT. It might be a good idea to keep a table of standard
1080 * VESA modes as well. The GTF may also not work for some displays,
1081 * such as, and especially, analog TV.
1084 * A valid info->monspecs, otherwise 'safe numbers' will be used.
1086 int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var, struct fb_info *info)
1088 struct __fb_timings timings;
1089 u32 interlace = 1, dscan = 1;
1090 u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax;
1093 * If monspecs are invalid, use values that are enough
1096 if (!info->monspecs.hfmax || !info->monspecs.vfmax ||
1097 !info->monspecs.dclkmax ||
1098 info->monspecs.hfmax < info->monspecs.hfmin ||
1099 info->monspecs.vfmax < info->monspecs.vfmin ||
1100 info->monspecs.dclkmax < info->monspecs.dclkmin) {
1101 hfmin = 29000; hfmax = 30000;
1102 vfmin = 60; vfmax = 60;
1103 dclkmin = 0; dclkmax = 25000000;
1105 hfmin = info->monspecs.hfmin;
1106 hfmax = info->monspecs.hfmax;
1107 vfmin = info->monspecs.vfmin;
1108 vfmax = info->monspecs.vfmax;
1109 dclkmin = info->monspecs.dclkmin;
1110 dclkmax = info->monspecs.dclkmax;
1113 memset(&timings, 0, sizeof(struct __fb_timings));
1114 timings.hactive = var->xres;
1115 timings.vactive = var->yres;
1116 if (var->vmode & FB_VMODE_INTERLACED) {
1117 timings.vactive /= 2;
1120 if (var->vmode & FB_VMODE_DOUBLE) {
1121 timings.vactive *= 2;
1125 switch (flags & ~FB_IGNOREMON) {
1126 case FB_MAXTIMINGS: /* maximize refresh rate */
1127 timings.hfreq = hfmax;
1128 fb_timings_hfreq(&timings);
1129 if (timings.vfreq > vfmax) {
1130 timings.vfreq = vfmax;
1131 fb_timings_vfreq(&timings);
1133 if (timings.dclk > dclkmax) {
1134 timings.dclk = dclkmax;
1135 fb_timings_dclk(&timings);
1138 case FB_VSYNCTIMINGS: /* vrefresh driven */
1139 timings.vfreq = val;
1140 fb_timings_vfreq(&timings);
1142 case FB_HSYNCTIMINGS: /* hsync driven */
1143 timings.hfreq = val;
1144 fb_timings_hfreq(&timings);
1146 case FB_DCLKTIMINGS: /* pixelclock driven */
1147 timings.dclk = PICOS2KHZ(val) * 1000;
1148 fb_timings_dclk(&timings);
1155 if (!(flags & FB_IGNOREMON) &&
1156 (timings.vfreq < vfmin || timings.vfreq > vfmax ||
1157 timings.hfreq < hfmin || timings.hfreq > hfmax ||
1158 timings.dclk < dclkmin || timings.dclk > dclkmax))
1161 var->pixclock = KHZ2PICOS(timings.dclk/1000);
1162 var->hsync_len = (timings.htotal * 8)/100;
1163 var->right_margin = (timings.hblank/2) - var->hsync_len;
1164 var->left_margin = timings.hblank - var->right_margin - var->hsync_len;
1166 var->vsync_len = (3 * interlace)/dscan;
1167 var->lower_margin = (1 * interlace)/dscan;
1168 var->upper_margin = (timings.vblank * interlace)/dscan -
1169 (var->vsync_len + var->lower_margin);
1174 int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
1178 void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
1182 void fb_destroy_modedb(struct fb_videomode *modedb)
1185 int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var,
1186 struct fb_info *info)
1190 #endif /* CONFIG_FB_MODE_HELPERS */
1193 * fb_validate_mode - validates var against monitor capabilities
1194 * @var: pointer to fb_var_screeninfo
1195 * @info: pointer to fb_info
1198 * Validates video mode against monitor capabilities specified in
1202 * A valid info->monspecs.
1204 int fb_validate_mode(const struct fb_var_screeninfo *var, struct fb_info *info)
1206 u32 hfreq, vfreq, htotal, vtotal, pixclock;
1207 u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax;
1210 * If monspecs are invalid, use values that are enough
1213 if (!info->monspecs.hfmax || !info->monspecs.vfmax ||
1214 !info->monspecs.dclkmax ||
1215 info->monspecs.hfmax < info->monspecs.hfmin ||
1216 info->monspecs.vfmax < info->monspecs.vfmin ||
1217 info->monspecs.dclkmax < info->monspecs.dclkmin) {
1218 hfmin = 29000; hfmax = 30000;
1219 vfmin = 60; vfmax = 60;
1220 dclkmin = 0; dclkmax = 25000000;
1222 hfmin = info->monspecs.hfmin;
1223 hfmax = info->monspecs.hfmax;
1224 vfmin = info->monspecs.vfmin;
1225 vfmax = info->monspecs.vfmax;
1226 dclkmin = info->monspecs.dclkmin;
1227 dclkmax = info->monspecs.dclkmax;
1232 pixclock = PICOS2KHZ(var->pixclock) * 1000;
1234 htotal = var->xres + var->right_margin + var->hsync_len +
1236 vtotal = var->yres + var->lower_margin + var->vsync_len +
1239 if (var->vmode & FB_VMODE_INTERLACED)
1241 if (var->vmode & FB_VMODE_DOUBLE)
1244 hfreq = pixclock/htotal;
1245 vfreq = hfreq/vtotal;
1247 return (vfreq < vfmin || vfreq > vfmax ||
1248 hfreq < hfmin || hfreq > hfmax ||
1249 pixclock < dclkmin || pixclock > dclkmax) ?
1253 EXPORT_SYMBOL(fb_parse_edid);
1254 EXPORT_SYMBOL(fb_edid_to_monspecs);
1256 EXPORT_SYMBOL(fb_get_mode);
1257 EXPORT_SYMBOL(fb_validate_mode);
1258 EXPORT_SYMBOL(fb_destroy_modedb);