* Copyright (c) 2006 Itronix Inc.

/* $NetBSD: edid.c,v 1.18 2022/09/25 21:27:39 thorpej Exp $ */

/*-
* Copyright (c) 2006 Itronix Inc.
* All rights reserved.
*
* Written by Garrett D'Amore for Itronix Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of Itronix Inc. may not be used to endorse
* or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: edid.c,v 1.18 2022/09/25 21:27:39 thorpej Exp $");

#ifdef _KERNEL
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h>
#else
#include <stdlib.h>
#include <inttypes.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#endif

#include <dev/videomode/videomode.h>
#include <dev/videomode/ediddevs.h>
#include <dev/videomode/edidreg.h>
#include <dev/videomode/edidvar.h>
#include <dev/videomode/vesagtf.h>

#define EDIDVERBOSE 1
#define DIVIDE(x,y) (((x) + ((y) / 2)) / (y))

/* These are reversed established timing order */
static const char *_edid_modes[] = {
"1280x1024x75",
"1024x768x75",
"1024x768x70",
"1024x768x60",
"1024x768x87i",
"832x624x74", /* rounding error, 74.55 Hz aka "832x624x75" */
"800x600x75",
"800x600x72",
"800x600x60",
"800x600x56",
"640x480x75",
"640x480x72",
"640x480x67",
"640x480x60",
"720x400x87", /* rounding error, 87.85 Hz aka "720x400x88" */
"720x400x70",
};

#ifdef EDIDVERBOSE
struct edid_vendor {
const char *vendor;
const char *name;
};

struct edid_product {
const char *vendor;
uint16_t product;
const char *name;
};

#include <dev/videomode/ediddevs_data.h>
#endif /* EDIDVERBOSE */

static const char *
edid_findvendor(const char *vendor)
{
#ifdef EDIDVERBOSE
int n;

for (n = 0; n < edid_nvendors; n++)
if (memcmp(edid_vendors[n].vendor, vendor, 3) == 0)
return edid_vendors[n].name;
#endif
return NULL;
}

static const char *
edid_findproduct(const char *vendor, uint16_t product)
{
#ifdef EDIDVERBOSE
int n;

for (n = 0; n < edid_nproducts; n++)
if (edid_products[n].product == product &&
memcmp(edid_products[n].vendor, vendor, 3) == 0)
return edid_products[n].name;
#endif /* EDIDVERBOSE */
return NULL;

}

static void
edid_strchomp(char *ptr)
{
for (;;) {
switch (*ptr) {
case '\0':
return;
case '\r':
case '\n':
*ptr = '\0';
return;
}
ptr++;
}
}

int
edid_is_valid(uint8_t *d)
{
int sum = 0, i;
uint8_t sig[8] = EDID_SIGNATURE;

if (memcmp(d, sig, 8) != 0)
return EINVAL;

for (i = 0; i < 128; i++)
sum += d[i];
if ((sum & 0xff) != 0)
return EINVAL;

return 0;
}

void
edid_print(struct edid_info *edid)
{
int i;

if (edid == NULL)
return;
printf("Vendor: [%s] %s\n", edid->edid_vendor, edid->edid_vendorname);
printf("Product: [%04X] %s\n", edid->edid_product,
edid->edid_productname);
printf("Serial number: %s\n", edid->edid_serial);
printf("Manufactured %d Week %d\n",
edid->edid_year, edid->edid_week);
printf("EDID Version %d.%d\n", edid->edid_version,
edid->edid_revision);
printf("EDID Comment: %s\n", edid->edid_comment);

printf("Video Input: %x\n", edid->edid_video_input);
if (edid->edid_video_input & EDID_VIDEO_INPUT_DIGITAL) {
printf("\tDigital");
if (edid->edid_video_input & EDID_VIDEO_INPUT_DFP1_COMPAT)
printf(" (DFP 1.x compatible)");
printf("\n");
} else {
printf("\tAnalog\n");
switch (EDID_VIDEO_INPUT_LEVEL(edid->edid_video_input)) {
case 0:
printf("\t-0.7, 0.3V\n");
break;
case 1:
printf("\t-0.714, 0.286V\n");
break;
case 2:
printf("\t-1.0, 0.4V\n");
break;
case 3:
printf("\t-0.7, 0.0V\n");
break;
}
if (edid->edid_video_input & EDID_VIDEO_INPUT_BLANK_TO_BLACK)
printf("\tBlank-to-black setup\n");
if (edid->edid_video_input & EDID_VIDEO_INPUT_SEPARATE_SYNCS)
printf("\tSeparate syncs\n");
if (edid->edid_video_input & EDID_VIDEO_INPUT_COMPOSITE_SYNC)
printf("\tComposite sync\n");
if (edid->edid_video_input & EDID_VIDEO_INPUT_SYNC_ON_GRN)
printf("\tSync on green\n");
if (edid->edid_video_input & EDID_VIDEO_INPUT_SERRATION)
printf("\tSerration vsync\n");
}

printf("Gamma: %d.%02d\n",
edid->edid_gamma / 100, edid->edid_gamma % 100);

printf("Max Size: %d cm x %d cm\n",
edid->edid_max_hsize, edid->edid_max_vsize);

printf("Features: %x\n", edid->edid_features);
if (edid->edid_features & EDID_FEATURES_STANDBY)
printf("\tDPMS standby\n");
if (edid->edid_features & EDID_FEATURES_SUSPEND)
printf("\tDPMS suspend\n");
if (edid->edid_features & EDID_FEATURES_ACTIVE_OFF)
printf("\tDPMS active-off\n");
switch (EDID_FEATURES_DISP_TYPE(edid->edid_features)) {
case EDID_FEATURES_DISP_TYPE_MONO:
printf("\tMonochrome\n");
break;
case EDID_FEATURES_DISP_TYPE_RGB:
printf("\tRGB\n");
break;
case EDID_FEATURES_DISP_TYPE_NON_RGB:
printf("\tMulticolor\n");
break;
case EDID_FEATURES_DISP_TYPE_UNDEFINED:
printf("\tUndefined monitor type\n");
break;
}
if (edid->edid_features & EDID_FEATURES_STD_COLOR)
printf("\tStandard color space\n");
if (edid->edid_features & EDID_FEATURES_PREFERRED_TIMING)
printf("\tPreferred timing\n");
if (edid->edid_features & EDID_FEATURES_DEFAULT_GTF)
printf("\tDefault GTF supported\n");

printf("Chroma Info:\n");
printf("\tRed X: 0.%03d\n", edid->edid_chroma.ec_redx);
printf("\tRed Y: 0.%03d\n", edid->edid_chroma.ec_redy);
printf("\tGrn X: 0.%03d\n", edid->edid_chroma.ec_greenx);
printf("\tGrn Y: 0.%03d\n", edid->edid_chroma.ec_greeny);
printf("\tBlu X: 0.%03d\n", edid->edid_chroma.ec_bluex);
printf("\tBlu Y: 0.%03d\n", edid->edid_chroma.ec_bluey);
printf("\tWht X: 0.%03d\n", edid->edid_chroma.ec_whitex);
printf("\tWht Y: 0.%03d\n", edid->edid_chroma.ec_whitey);

if (edid->edid_have_range) {
printf("Range:\n");
printf("\tHorizontal: %d - %d kHz\n",
edid->edid_range.er_min_hfreq,
edid->edid_range.er_max_hfreq);
printf("\tVertical: %d - %d Hz\n",
edid->edid_range.er_min_vfreq,
edid->edid_range.er_max_vfreq);
printf("\tMax Dot Clock: %d MHz\n",
edid->edid_range.er_max_clock);
if (edid->edid_range.er_have_gtf2) {
printf("\tGTF2 hfreq: %d\n",
edid->edid_range.er_gtf2_hfreq);
printf("\tGTF2 C: %d\n", edid->edid_range.er_gtf2_c);
printf("\tGTF2 M: %d\n", edid->edid_range.er_gtf2_m);
printf("\tGTF2 J: %d\n", edid->edid_range.er_gtf2_j);
printf("\tGTF2 K: %d\n", edid->edid_range.er_gtf2_k);
}
}
printf("Video modes:\n");
for (i = 0; i < edid->edid_nmodes; i++) {
printf("\t%dx%d @ %dHz",
edid->edid_modes[i].hdisplay,
edid->edid_modes[i].vdisplay,
DIVIDE(DIVIDE(edid->edid_modes[i].dot_clock * 1000,
edid->edid_modes[i].htotal), edid->edid_modes[i].vtotal));
printf(" (%d %d %d %d %d %d %d",
edid->edid_modes[i].dot_clock,
edid->edid_modes[i].hsync_start,
edid->edid_modes[i].hsync_end,
edid->edid_modes[i].htotal,
edid->edid_modes[i].vsync_start,
edid->edid_modes[i].vsync_end,
edid->edid_modes[i].vtotal);
printf(" %s%sH %s%sV)\n",
edid->edid_modes[i].flags & VID_PHSYNC ? "+" : "",
edid->edid_modes[i].flags & VID_NHSYNC ? "-" : "",
edid->edid_modes[i].flags & VID_PVSYNC ? "+" : "",
edid->edid_modes[i].flags & VID_NVSYNC ? "-" : "");
}
if (edid->edid_preferred_mode)
printf("Preferred mode: %dx%d @ %dHz\n",
edid->edid_preferred_mode->hdisplay,
edid->edid_preferred_mode->vdisplay,
DIVIDE(DIVIDE(edid->edid_preferred_mode->dot_clock * 1000,
edid->edid_preferred_mode->htotal),
edid->edid_preferred_mode->vtotal));

printf("Number of extension blocks: %d\n", edid->edid_ext_block_count);
}

static const struct videomode *
edid_mode_lookup_list(const char *name)
{
int i;

for (i = 0; i < videomode_count; i++)
if (strcmp(name, videomode_list[i].name) == 0)
return &videomode_list[i];
return NULL;
}

static struct videomode *
edid_search_mode(struct edid_info *edid, const struct videomode *mode)
{
int refresh, i;

refresh = DIVIDE(DIVIDE(mode->dot_clock * 1000,
mode->htotal), mode->vtotal);
for (i = 0; i < edid->edid_nmodes; i++) {
if (mode->hdisplay == edid->edid_modes[i].hdisplay &&
mode->vdisplay == edid->edid_modes[i].vdisplay &&
refresh == DIVIDE(DIVIDE(
edid->edid_modes[i].dot_clock * 1000,
edid->edid_modes[i].htotal), edid->edid_modes[i].vtotal)) {
return &edid->edid_modes[i];
}
}
return NULL;
}

static int
edid_std_timing(uint8_t *data, struct videomode *vmp)
{
unsigned x, y, f;
const struct videomode *lookup;
char name[80];

if ((data[0] == 1 && data[1] == 1) ||
(data[0] == 0 && data[1] == 0) ||
(data[0] == 0x20 && data[1] == 0x20))
return 0;

x = EDID_STD_TIMING_HRES(data);
switch (EDID_STD_TIMING_RATIO(data)) {
case EDID_STD_TIMING_RATIO_16_10:
y = x * 10 / 16;
break;
case EDID_STD_TIMING_RATIO_4_3:
y = x * 3 / 4;
break;
case EDID_STD_TIMING_RATIO_5_4:
y = x * 4 / 5;
break;
case EDID_STD_TIMING_RATIO_16_9:
default:
y = x * 9 / 16;
break;
}
f = EDID_STD_TIMING_VFREQ(data);

/* first try to lookup the mode as a DMT timing */
snprintf(name, sizeof(name), "%dx%dx%d", x, y, f);
if ((lookup = edid_mode_lookup_list(name)) != NULL) {
*vmp = *lookup;
} else {
/* failing that, calculate it using gtf */
/*
* Hmm. I'm not using alternate GTF timings, which
* could, in theory, be present.
*/
vesagtf_mode(x, y, f, vmp);
}
return 1;
}

static int
edid_det_timing(uint8_t *data, struct videomode *vmp)
{
unsigned hactive, hblank, hsyncwid, hsyncoff;
unsigned vactive, vblank, vsyncwid, vsyncoff;
uint8_t flags;

flags = EDID_DET_TIMING_FLAGS(data);

/* we don't support stereo modes (for now) */
if (flags & (EDID_DET_TIMING_FLAG_STEREO |
EDID_DET_TIMING_FLAG_STEREO_MODE))
return 0;

vmp->dot_clock = EDID_DET_TIMING_DOT_CLOCK(data) / 1000;

hactive = EDID_DET_TIMING_HACTIVE(data);
hblank = EDID_DET_TIMING_HBLANK(data);
hsyncwid = EDID_DET_TIMING_HSYNC_WIDTH(data);
hsyncoff = EDID_DET_TIMING_HSYNC_OFFSET(data);

vactive = EDID_DET_TIMING_VACTIVE(data);
vblank = EDID_DET_TIMING_VBLANK(data);
vsyncwid = EDID_DET_TIMING_VSYNC_WIDTH(data);
vsyncoff = EDID_DET_TIMING_VSYNC_OFFSET(data);

/* Borders are contained within the blank areas. */

vmp->hdisplay = hactive;
vmp->htotal = hactive + hblank;
vmp->hsync_start = hactive + hsyncoff;
vmp->hsync_end = vmp->hsync_start + hsyncwid;

vmp->vdisplay = vactive;
vmp->vtotal = vactive + vblank;
vmp->vsync_start = vactive + vsyncoff;
vmp->vsync_end = vmp->vsync_start + vsyncwid;

vmp->flags = 0;

if (flags & EDID_DET_TIMING_FLAG_INTERLACE)
vmp->flags |= VID_INTERLACE;
if (flags & EDID_DET_TIMING_FLAG_HSYNC_POSITIVE)
vmp->flags |= VID_PHSYNC;
else
vmp->flags |= VID_NHSYNC;

if (flags & EDID_DET_TIMING_FLAG_VSYNC_POSITIVE)
vmp->flags |= VID_PVSYNC;
else
vmp->flags |= VID_NVSYNC;

return 1;
}

static void bump_preferred_mode(struct edid_info *edid, struct videomode *m)
{
/*
* XXX
* Iiyama 4800 series monitors may have their native resolution in the
* 2nd detailed timing descriptor instead of the 1st. Try to detect
* that here and pick the native mode anyway.
*/
if (edid->edid_preferred_mode == NULL) {
edid->edid_preferred_mode = m;
} else if ((strncmp((char*)edid->edid_vendor, "IVM", 3) == 0) &&
(edid->edid_product == 0x4800) &&
(edid->edid_preferred_mode->dot_clock < m->dot_clock))
edid->edid_preferred_mode = m;
}

static void
edid_block(struct edid_info *edid, uint8_t *data)
{
int i;
struct videomode mode, *exist_mode;

if (EDID_BLOCK_IS_DET_TIMING(data)) {
if (!edid_det_timing(data, &mode))
return;
/* Does this mode already exist? */
exist_mode = edid_search_mode(edid, &mode);
if (exist_mode != NULL) {
*exist_mode = mode;
bump_preferred_mode(edid, exist_mode);
} else {
edid->edid_modes[edid->edid_nmodes] = mode;
bump_preferred_mode(edid,
&edid->edid_modes[edid->edid_nmodes]);
edid->edid_nmodes++;
}
return;
}

switch (EDID_BLOCK_TYPE(data)) {
case EDID_DESC_BLOCK_TYPE_SERIAL:
memcpy(edid->edid_serial, data + EDID_DESC_ASCII_DATA_OFFSET,
EDID_DESC_ASCII_DATA_LEN);
edid->edid_serial[sizeof(edid->edid_serial) - 1] = 0;
break;

case EDID_DESC_BLOCK_TYPE_ASCII:
memset(edid->edid_comment, 0, sizeof(edid->edid_comment));
memcpy(edid->edid_comment, data + EDID_DESC_ASCII_DATA_OFFSET,
EDID_DESC_ASCII_DATA_LEN);
edid->edid_comment[sizeof(edid->edid_comment) - 1] = 0;
break;

case EDID_DESC_BLOCK_TYPE_RANGE:
edid->edid_have_range = 1;
edid->edid_range.er_min_vfreq = EDID_DESC_RANGE_MIN_VFREQ(data);
edid->edid_range.er_max_vfreq = EDID_DESC_RANGE_MAX_VFREQ(data);
edid->edid_range.er_min_hfreq = EDID_DESC_RANGE_MIN_HFREQ(data);
edid->edid_range.er_max_hfreq = EDID_DESC_RANGE_MAX_HFREQ(data);
edid->edid_range.er_max_clock = EDID_DESC_RANGE_MAX_CLOCK(data);
if (!EDID_DESC_RANGE_HAVE_GTF2(data))
break;
edid->edid_range.er_have_gtf2 = 1;
edid->edid_range.er_gtf2_hfreq =
EDID_DESC_RANGE_GTF2_HFREQ(data);
edid->edid_range.er_gtf2_c = EDID_DESC_RANGE_GTF2_C(data);
edid->edid_range.er_gtf2_m = EDID_DESC_RANGE_GTF2_M(data);
edid->edid_range.er_gtf2_j = EDID_DESC_RANGE_GTF2_J(data);
edid->edid_range.er_gtf2_k = EDID_DESC_RANGE_GTF2_K(data);
break;

case EDID_DESC_BLOCK_TYPE_NAME:
/* copy the product name into place */
memcpy(edid->edid_productname,
data + EDID_DESC_ASCII_DATA_OFFSET,
EDID_DESC_ASCII_DATA_LEN);
break;

case EDID_DESC_BLOCK_TYPE_STD_TIMING:
data += EDID_DESC_STD_TIMING_START;
for (i = 0; i < EDID_DESC_STD_TIMING_COUNT; i++) {
if (edid_std_timing(data, &mode)) {
/* Does this mode already exist? */
exist_mode = edid_search_mode(edid, &mode);
if (exist_mode == NULL) {
edid->edid_modes[edid->edid_nmodes] =
mode;
edid->edid_nmodes++;
}
}
data += 2;
}
break;

case EDID_DESC_BLOCK_TYPE_COLOR_POINT:
/* XXX: not implemented yet */
break;
}
}

/*
* Gets EDID version in BCD, e.g. EDID v1.3 returned as 0x0103
*/
int
edid_parse(uint8_t *data, struct edid_info *edid)
{
uint16_t manfid, estmodes;
const struct videomode *vmp;
int i;
const char *name;
int max_dotclock = 0;
int mhz;

if (edid_is_valid(data) != 0)
return -1;

/* get product identification */
manfid = EDID_VENDOR_ID(data);
edid->edid_vendor[0] = EDID_MANFID_0(manfid);
edid->edid_vendor[1] = EDID_MANFID_1(manfid);
edid->edid_vendor[2] = EDID_MANFID_2(manfid);
edid->edid_vendor[3] = 0; /* null terminate for convenience */

edid->edid_product = data[EDID_OFFSET_PRODUCT_ID] +
(data[EDID_OFFSET_PRODUCT_ID + 1] << 8);

name = edid_findvendor((char *)edid->edid_vendor);
if (name != NULL)
strlcpy(edid->edid_vendorname, name,
sizeof(edid->edid_vendorname));
else
edid->edid_vendorname[0] = '\0';

name = edid_findproduct((char *)edid->edid_vendor, edid->edid_product);
if (name != NULL)
strlcpy(edid->edid_productname, name,
sizeof(edid->edid_productname));
else
edid->edid_productname[0] = '\0';

snprintf(edid->edid_serial, sizeof(edid->edid_serial), "%08x",
EDID_SERIAL_NUMBER(data));

edid->edid_comment[0] = '\0';

edid->edid_week = EDID_WEEK(data);
edid->edid_year = EDID_YEAR(data);

/* get edid revision */
edid->edid_version = EDID_VERSION(data);
edid->edid_revision = EDID_REVISION(data);

edid->edid_video_input = EDID_VIDEO_INPUT(data);
edid->edid_max_hsize = EDID_MAX_HSIZE(data);
edid->edid_max_vsize = EDID_MAX_VSIZE(data);

edid->edid_gamma = EDID_GAMMA(data);
edid->edid_features = EDID_FEATURES(data);

edid->edid_chroma.ec_redx = EDID_CHROMA_REDX(data);
edid->edid_chroma.ec_redy = EDID_CHROMA_REDX(data);
edid->edid_chroma.ec_greenx = EDID_CHROMA_GREENX(data);
edid->edid_chroma.ec_greeny = EDID_CHROMA_GREENY(data);
edid->edid_chroma.ec_bluex = EDID_CHROMA_BLUEX(data);
edid->edid_chroma.ec_bluey = EDID_CHROMA_BLUEY(data);
edid->edid_chroma.ec_whitex = EDID_CHROMA_WHITEX(data);
edid->edid_chroma.ec_whitey = EDID_CHROMA_WHITEY(data);

edid->edid_ext_block_count = EDID_EXT_BLOCK_COUNT(data);

/* lookup established modes */
edid->edid_nmodes = 0;
edid->edid_preferred_mode = NULL;
estmodes = EDID_EST_TIMING(data);
/* Iterate in esztablished timing order */
for (i = 15; i >= 0; i--) {
if (estmodes & (1 << i)) {
vmp = edid_mode_lookup_list(_edid_modes[i]);
if (vmp != NULL) {
edid->edid_modes[edid->edid_nmodes] = *vmp;
edid->edid_nmodes++;
}
#ifdef DIAGNOSTIC
else
printf("no data for est. mode %s\n",
_edid_modes[i]);
#endif
}
}

/* do standard timing section */
for (i = 0; i < EDID_STD_TIMING_COUNT; i++) {
struct videomode mode, *exist_mode;
if (edid_std_timing(data + EDID_OFFSET_STD_TIMING + i * 2,
&mode)) {
/* Does this mode already exist? */
exist_mode = edid_search_mode(edid, &mode);
if (exist_mode == NULL) {
edid->edid_modes[edid->edid_nmodes] = mode;
edid->edid_nmodes++;
}
}
}

/* do detailed timings and descriptors */
for (i = 0; i < EDID_BLOCK_COUNT; i++) {
edid_block(edid, data + EDID_OFFSET_DESC_BLOCK +
i * EDID_BLOCK_SIZE);
}

edid_strchomp(edid->edid_vendorname);
edid_strchomp(edid->edid_productname);
edid_strchomp(edid->edid_serial);
edid_strchomp(edid->edid_comment);

/*
* XXX
* some monitors lie about their maximum supported dot clock
* by claiming to support modes which need a higher dot clock
* than the stated maximum.
* For sanity's sake we bump it to the highest dot clock we find
* in the list of supported modes
*/
for (i = 0; i < edid->edid_nmodes; i++)
if (edid->edid_modes[i].dot_clock > max_dotclock)
max_dotclock = edid->edid_modes[i].dot_clock;

#ifdef _KERNEL
aprint_debug("max_dotclock according to supported modes: %d\n",
max_dotclock);
#endif

mhz = (max_dotclock + 999) / 1000;

if (edid->edid_have_range) {
if (mhz > edid->edid_range.er_max_clock)
edid->edid_range.er_max_clock = mhz;
} else
edid->edid_range.er_max_clock = mhz;

return 0;
}