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// Copyright (C) 2017 Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>
// Copyright (C) 2021 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include <QtCore/QFile>
#include <QtCore/QByteArrayView>
#include "qedidparser_p.h"
#include "qedidvendortable_p.h"
#define EDID_DESCRIPTOR_ALPHANUMERIC_STRING 0xfe
#define EDID_DESCRIPTOR_PRODUCT_NAME 0xfc
#define EDID_DESCRIPTOR_SERIAL_NUMBER 0xff
#define EDID_DATA_BLOCK_COUNT 4
#define EDID_OFFSET_DATA_BLOCKS 0x36
#define EDID_OFFSET_LAST_BLOCK 0x6c
#define EDID_OFFSET_PNP_ID 0x08
#define EDID_OFFSET_SERIAL 0x0c
#define EDID_PHYSICAL_WIDTH 0x15
#define EDID_OFFSET_PHYSICAL_HEIGHT 0x16
#define EDID_TRANSFER_FUNCTION 0x17
#define EDID_FEATURE_SUPPORT 0x18
#define EDID_CHROMATICITIES_BLOCK 0x19
QT_BEGIN_NAMESPACE
using namespace Qt::StringLiterals;
static QString lookupVendorIdInSystemDatabase(QByteArrayView id)
{
QString result;
const QString fileName = "/usr/share/hwdata/pnp.ids"_L1;
QFile file(fileName);
if (!file.open(QFile::ReadOnly))
return result;
// On Ubuntu 20.04 the longest line in the file is 85 bytes, so this
// leaves plenty of room...
constexpr int MaxLineSize = 512;
char buf[MaxLineSize];
while (!file.atEnd()) {
auto read = file.readLine(buf, MaxLineSize);
if (read < 0 || read == MaxLineSize) // read error
break;
QByteArrayView line(buf, read - 1); // -1 to remove the trailing newline
if (line.isEmpty())
continue;
if (line.startsWith('#'))
continue;
auto tabPosition = line.indexOf('\t');
if (tabPosition <= 0) // no vendor id
continue;
if (tabPosition + 1 == line.size()) // no vendor name
continue;
if (line.first(tabPosition) == id) {
auto vendor = line.sliced(tabPosition + 1);
result = QString::fromUtf8(vendor.data(), vendor.size());
break;
}
}
return result;
}
bool QEdidParser::parse(const QByteArray &blob)
{
const quint8 *data = reinterpret_cast<const quint8 *>(blob.constData());
const size_t length = blob.size();
// Verify header
if (length < 128)
return false;
if (data[0] != 0x00 || data[1] != 0xff)
return false;
/* Decode the PNP ID from three 5 bit words packed into 2 bytes
* /--08--\/--09--\
* 7654321076543210
* |\---/\---/\---/
* R C1 C2 C3 */
char pnpId[3];
pnpId[0] = 'A' + ((data[EDID_OFFSET_PNP_ID] & 0x7c) / 4) - 1;
pnpId[1] = 'A' + ((data[EDID_OFFSET_PNP_ID] & 0x3) * 8) + ((data[EDID_OFFSET_PNP_ID + 1] & 0xe0) / 32) - 1;
pnpId[2] = 'A' + (data[EDID_OFFSET_PNP_ID + 1] & 0x1f) - 1;
// Clear manufacturer
manufacturer = QString();
// Serial number, will be overwritten by an ASCII descriptor
// when and if it will be found
quint32 serial = data[EDID_OFFSET_SERIAL]
+ (data[EDID_OFFSET_SERIAL + 1] << 8)
+ (data[EDID_OFFSET_SERIAL + 2] << 16)
+ (data[EDID_OFFSET_SERIAL + 3] << 24);
if (serial > 0)
serialNumber = QString::number(serial);
else
serialNumber = QString();
// Parse EDID data
for (int i = 0; i < EDID_DATA_BLOCK_COUNT; ++i) {
const uint offset = EDID_OFFSET_DATA_BLOCKS + i * 18;
if (data[offset] != 0 || data[offset + 1] != 0 || data[offset + 2] != 0)
continue;
if (data[offset + 3] == EDID_DESCRIPTOR_PRODUCT_NAME)
model = parseEdidString(&data[offset + 5]);
else if (data[offset + 3] == EDID_DESCRIPTOR_ALPHANUMERIC_STRING)
identifier = parseEdidString(&data[offset + 5]);
else if (data[offset + 3] == EDID_DESCRIPTOR_SERIAL_NUMBER)
serialNumber = parseEdidString(&data[offset + 5]);
}
// Try to use cache first because it is potentially more updated
manufacturer = lookupVendorIdInSystemDatabase(pnpId);
if (manufacturer.isEmpty()) {
// Find the manufacturer from the vendor lookup table
const auto compareVendorId = [](const VendorTable &vendor, const char *str)
{
return strncmp(vendor.id, str, 3) < 0;
};
const auto b = std::begin(q_edidVendorTable);
const auto e = std::end(q_edidVendorTable);
auto it = std::lower_bound(b,
e,
pnpId,
compareVendorId);
if (it != e && strncmp(it->id, pnpId, 3) == 0)
manufacturer = QString::fromUtf8(it->name);
}
// If we don't know the manufacturer, fallback to PNP ID
if (manufacturer.isEmpty())
manufacturer = QString::fromUtf8(pnpId, std::size(pnpId));
// Physical size
physicalSize = QSizeF(data[EDID_PHYSICAL_WIDTH], data[EDID_OFFSET_PHYSICAL_HEIGHT]) * 10;
// Gamma and transfer function
const uint igamma = data[EDID_TRANSFER_FUNCTION];
if (igamma != 0xff) {
gamma = 1.0 + (igamma / 100.0f);
useTables = false;
} else {
gamma = 0.0; // Defined in DI-EXT
useTables = true;
}
sRgb = data[EDID_FEATURE_SUPPORT] & 0x04;
// Chromaticities
int rx = (data[EDID_CHROMATICITIES_BLOCK] >> 6) & 0x03;
int ry = (data[EDID_CHROMATICITIES_BLOCK] >> 4) & 0x03;
int gx = (data[EDID_CHROMATICITIES_BLOCK] >> 2) & 0x03;
int gy = (data[EDID_CHROMATICITIES_BLOCK] >> 0) & 0x03;
int bx = (data[EDID_CHROMATICITIES_BLOCK + 1] >> 6) & 0x03;
int by = (data[EDID_CHROMATICITIES_BLOCK + 1] >> 4) & 0x03;
int wx = (data[EDID_CHROMATICITIES_BLOCK + 1] >> 2) & 0x03;
int wy = (data[EDID_CHROMATICITIES_BLOCK + 1] >> 0) & 0x03;
rx |= data[EDID_CHROMATICITIES_BLOCK + 2] << 2;
ry |= data[EDID_CHROMATICITIES_BLOCK + 3] << 2;
gx |= data[EDID_CHROMATICITIES_BLOCK + 4] << 2;
gy |= data[EDID_CHROMATICITIES_BLOCK + 5] << 2;
bx |= data[EDID_CHROMATICITIES_BLOCK + 6] << 2;
by |= data[EDID_CHROMATICITIES_BLOCK + 7] << 2;
wx |= data[EDID_CHROMATICITIES_BLOCK + 8] << 2;
wy |= data[EDID_CHROMATICITIES_BLOCK + 9] << 2;
redChromaticity.setX(rx * (1.0f / 1024.0f));
redChromaticity.setY(ry * (1.0f / 1024.0f));
greenChromaticity.setX(gx * (1.0f / 1024.0f));
greenChromaticity.setY(gy * (1.0f / 1024.0f));
blueChromaticity.setX(bx * (1.0f / 1024.0f));
blueChromaticity.setY(by * (1.0f / 1024.0f));
whiteChromaticity.setX(wx * (1.0f / 1024.0f));
whiteChromaticity.setY(wy * (1.0f / 1024.0f));
// Find extensions
for (uint i = 1; i < length / 128; ++i) {
uint extensionId = data[i * 128];
if (extensionId == 0x40) { // DI-EXT
// 0x0E (sub-pixel layout)
// 0x20->0x22 (bits per color)
// 0x51->0x7e Transfer characteristics
const uchar desc = data[i * 128 + 0x51];
const uchar len = desc & 0x3f;
if ((desc & 0xc0) == 0x40) {
if (len > 45)
return false;
QList<uint16_t> whiteTRC;
whiteTRC.reserve(len + 1);
for (uint j = 0; j < len; ++j)
whiteTRC[j] = data[0x52 + j] * 0x101;
whiteTRC[len] = 0xffff;
tables.append(whiteTRC);
} else if ((desc & 0xc0) == 0x80) {
if (len > 15)
return false;
QList<uint16_t> redTRC;
QList<uint16_t> greenTRC;
QList<uint16_t> blueTRC;
blueTRC.reserve(len + 1);
greenTRC.reserve(len + 1);
redTRC.reserve(len + 1);
for (uint j = 0; j < len; ++j)
blueTRC[j] = data[0x52 + j] * 0x101;
blueTRC[len] = 0xffff;
for (uint j = 0; j < len; ++j)
greenTRC[j] = data[0x61 + j] * 0x101;
greenTRC[len] = 0xffff;
for (uint j = 0; j < len; ++j)
redTRC[j] = data[0x70 + j] * 0x101;
redTRC[len] = 0xffff;
tables.append(redTRC);
tables.append(greenTRC);
tables.append(blueTRC);
}
}
}
return true;
}
QString QEdidParser::parseEdidString(const quint8 *data)
{
QByteArray buffer(reinterpret_cast<const char *>(data), 13);
for (int i = 0; i < buffer.size(); ++i) {
// If there are less than 13 characters in the string, the string
// is terminated with the ASCII code ‘0Ah’ (line feed) and padded
// with ASCII code ‘20h’ (space). See EDID 1.4, sections 3.10.3.1,
// 3.10.3.2, and 3.10.3.4.
if (buffer[i] == '\n') {
buffer.truncate(i);
break;
}
// Replace non-printable characters with dash
if (buffer[i] < '\040' || buffer[i] > '\176')
buffer[i] = '-';
}
return QString::fromLatin1(buffer);
}
QT_END_NAMESPACE
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