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- // Copyright 2014 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "ui/display/util/edid_parser.h"
- #include <stddef.h>
- #include <algorithm>
- #include <bitset>
- #include "base/check.h"
- #include "base/hash/hash.h"
- #include "base/hash/md5.h"
- #include "base/metrics/histogram_functions.h"
- #include "base/strings/string_number_conversions.h"
- #include "base/strings/string_util.h"
- #include "base/strings/stringprintf.h"
- #include "base/sys_byteorder.h"
- #include "third_party/skia/include/core/SkColorSpace.h"
- #include "ui/display/util/display_util.h"
- #include "ui/gfx/geometry/size.h"
- namespace display {
- namespace {
- constexpr char kParseEdidFailureMetric[] = "Display.ParseEdidFailure";
- constexpr char kParseExternalDisplayEdidOptionalsMetric[] =
- "Display.External.ParseEdidOptionals";
- constexpr char kBlockZeroSerialNumberTypeMetric[] =
- "Display.External.BlockZeroSerialNumberType";
- constexpr char kNumOfSerialNumbersProvidedByExternalDisplay[] =
- "Display.External.NumOfSerialNumbersProvided";
- constexpr uint8_t kMaxSerialNumberCount = 2;
- // These values are persisted to logs. Entries should not be renumbered and
- // numeric values should never be reused.
- enum class ParseEdidFailure {
- kNoError = 0,
- kManufacturerId = 1,
- kProductId = 2,
- kYearOfManufacture = 3,
- kBitsPerChannel = 4,
- kGamma = 5,
- kChromaticityCoordinates = 6,
- kDisplayName = 7,
- kExtensions = 8,
- kSerialNumber = 9,
- kWeekOfManufacture = 10,
- kPhysicalSize = 11,
- kMaxValue = kPhysicalSize,
- };
- // These values are persisted to logs. Entries should not be renumbered and
- // numeric values should never be reused. This enum is used to track the
- // availability (or lack thereof) of optional fields during EDID parsing.
- enum class ParseEdidOptionals {
- kAllAvailable = 0,
- kBlockZeroSerialNumber = 1,
- kDescriptorBlockSerialNumber = 2,
- kWeekOfManufacture = 3,
- kPhysicalSize = 4,
- kMaxValue = kPhysicalSize,
- };
- // These values are persisted to logs. Entries should not be renumbered and
- // numeric values should never be reused. This enum is used to track the
- // serial number types that can be retrieved from an EDID's block zero.
- enum class BlockZeroSerialNumberType {
- kNormal = 0,
- kRepeatingPattern = 1,
- kNoSerialNumber = 2,
- kMaxValue = kNoSerialNumber,
- };
- BlockZeroSerialNumberType GetSerialNumberType(const uint8_t serial_number[],
- size_t size) {
- int sum = serial_number[0];
- bool all_equal = true;
- for (size_t i = 1; i < size; ++i) {
- sum += serial_number[i];
- if (serial_number[i - 1] != serial_number[i])
- all_equal = false;
- }
- if (sum == 0)
- return BlockZeroSerialNumberType::kNoSerialNumber;
- if (all_equal)
- return BlockZeroSerialNumberType::kRepeatingPattern;
- return BlockZeroSerialNumberType::kNormal;
- }
- } // namespace
- EdidParser::EdidParser(const std::vector<uint8_t>& edid_blob, bool is_external)
- : is_external_display_(is_external),
- manufacturer_id_(0),
- product_id_(0),
- year_of_manufacture_(display::kInvalidYearOfManufacture),
- gamma_(0.0),
- bits_per_channel_(-1),
- primaries_({0}) {
- ParseEdid(edid_blob);
- }
- EdidParser::~EdidParser() = default;
- uint32_t EdidParser::GetProductCode() const {
- return ((static_cast<uint32_t>(manufacturer_id_) << 16) |
- (static_cast<uint32_t>(product_id_)));
- }
- int64_t EdidParser::GetIndexBasedDisplayId(uint8_t output_index) const {
- // Generates product specific value from product_name instead of product code.
- // See https://crbug.com/240341
- const uint32_t product_code_hash =
- display_name_.empty() ? 0 : base::Hash(display_name_);
- // An ID based on display's index will be assigned later if this call fails.
- return GenerateDisplayID(manufacturer_id_, product_code_hash, output_index);
- }
- int64_t EdidParser::GetEdidBasedDisplayId() const {
- const std::string string_to_hash =
- base::NumberToString(manufacturer_id_) +
- base::NumberToString(product_id_) + display_name_ +
- base::NumberToString(week_of_manufacture()) +
- base::NumberToString(year_of_manufacture_) + max_image_size().ToString() +
- block_zero_serial_number_hash() + descriptor_block_serial_number_hash();
- return static_cast<int64_t>(base::PersistentHash(string_to_hash));
- }
- // static
- void EdidParser::SplitProductCodeInManufacturerIdAndProductId(
- int64_t product_code,
- uint16_t* manufacturer_id,
- uint16_t* product_id) {
- DCHECK(manufacturer_id);
- DCHECK(product_id);
- // Undo GetProductCode() packing.
- *product_id = product_code & 0xFFFF;
- *manufacturer_id = (product_code >> 16) & 0xFFFF;
- }
- // static
- std::string EdidParser::ManufacturerIdToString(uint16_t manufacturer_id) {
- // Constants are taken from "VESA Enhanced EDID Standard" Release A, Revision
- // 2, Sep 2006, Sec 3.4.1 "ID Manufacturer Name: 2 Bytes". Essentially these
- // are 3 5-bit ASCII characters packed in 2 bytes, where 1 means 'A', etc.
- constexpr uint8_t kFiveBitAsciiMask = 0x1F;
- constexpr char kFiveBitToAsciiOffset = 'A' - 1;
- constexpr size_t kSecondLetterOffset = 5;
- constexpr size_t kFirstLetterOffset = 10;
- char out[4] = {};
- out[2] = (manufacturer_id & kFiveBitAsciiMask) + kFiveBitToAsciiOffset;
- out[1] = ((manufacturer_id >> kSecondLetterOffset) & kFiveBitAsciiMask) +
- kFiveBitToAsciiOffset;
- out[0] = ((manufacturer_id >> kFirstLetterOffset) & kFiveBitAsciiMask) +
- kFiveBitToAsciiOffset;
- return out;
- }
- // static
- std::string EdidParser::ProductIdToString(uint16_t product_id) {
- // From "VESA Enhanced EDID Standard" Release A, Revision 2, Sep 2006, Sec
- // 3.4.2 "ID Product Code: 2 Bytes": "The ID product code field, [...]
- // contains a 2-byte manufacturer assigned product code. [...] The 2 byte
- // number is stored in hex with the least significant byte listed first."
- uint8_t lower_char = (product_id >> 8) & 0xFF;
- uint8_t upper_char = product_id & 0xFF;
- return base::StringPrintf("%02X%02X", upper_char, lower_char);
- }
- void EdidParser::ParseEdid(const std::vector<uint8_t>& edid) {
- // See http://en.wikipedia.org/wiki/Extended_display_identification_data
- // for the details of EDID data format. We use the following data:
- // bytes 8-9: manufacturer EISA ID, in big-endian
- // bytes 10-11: manufacturer product code, in little-endian
- constexpr size_t kManufacturerOffset = 8;
- constexpr size_t kManufacturerLength = 2;
- constexpr size_t kProductIdOffset = 10;
- constexpr size_t kProductIdLength = 2;
- if (edid.size() < kManufacturerOffset + kManufacturerLength) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kManufacturerId);
- return; // Any other fields below are beyond this edid offset.
- }
- // ICC filename is generated based on these ids. We always read this as big
- // endian so that the file name matches bytes 8-11 as they appear in EDID.
- manufacturer_id_ =
- (edid[kManufacturerOffset] << 8) + edid[kManufacturerOffset + 1];
- if (edid.size() < kProductIdOffset + kProductIdLength) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kProductId);
- return; // Any other fields below are beyond this edid offset.
- }
- product_id_ = (edid[kProductIdOffset] << 8) + edid[kProductIdOffset + 1];
- // Bytes 12-15: dislay serial number, in little-endian (LSB). This field is
- // optional and its absence is marked by having all bytes set to 0x00.
- // Values do not represent ASCII characters.
- constexpr size_t kSerialNumberOffset = 12;
- constexpr size_t kSerialNumberLength = 4;
- if (edid.size() < kSerialNumberOffset + kSerialNumberLength) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kSerialNumber);
- return; // Any other fields below are beyond this edid offset.
- }
- const uint8_t serial_number_bytes[kSerialNumberLength] = {
- edid[kSerialNumberOffset], edid[kSerialNumberOffset + 1],
- edid[kSerialNumberOffset + 2], edid[kSerialNumberOffset + 3]};
- // Report the type of serial number encountered in block zero of external
- // displays: empty (==0), repeating pattern (e.g. 01010101 or 0F0F0F0F),
- // or normal.
- if (is_external_display_) {
- base::UmaHistogramEnumeration(
- kBlockZeroSerialNumberTypeMetric,
- GetSerialNumberType(serial_number_bytes,
- std::size(serial_number_bytes)));
- }
- const uint32_t serial_number =
- serial_number_bytes[0] + (serial_number_bytes[1] << 8) +
- (serial_number_bytes[2] << 16) + (serial_number_bytes[3] << 24);
- if (serial_number) {
- block_zero_serial_number_hash_ =
- base::MD5String(base::NumberToString(serial_number));
- }
- // Constants are taken from "VESA Enhanced EDID Standard" Release A, Revision
- // 2, Sep 2006, Sec 3.4.4 "Week and Year of Manufacture or Model Year: 2
- // Bytes".
- constexpr size_t kWeekOfManufactureOffset = 16;
- constexpr uint32_t kValidWeekValueUpperBound = 0x36;
- constexpr uint32_t kModelYearMarker = 0xFF;
- if (edid.size() < kWeekOfManufactureOffset + 1) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kWeekOfManufacture);
- return; // Any other fields below are beyond this edid offset.
- }
- {
- const uint8_t byte_data = edid[kWeekOfManufactureOffset];
- // Store the value if it's within the range of 1-54 or equals to 0xFF.
- if ((byte_data > 0x00 && byte_data <= kValidWeekValueUpperBound) ||
- byte_data == kModelYearMarker) {
- week_of_manufacture_ = byte_data;
- }
- }
- constexpr size_t kYearOfManufactureOffset = 17;
- constexpr uint32_t kValidYearValueLowerBound = 0x10;
- constexpr int32_t kYearOffset = 1990;
- if (edid.size() < kYearOfManufactureOffset + 1) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kYearOfManufacture);
- return; // Any other fields below are beyond this edid offset.
- }
- {
- const uint8_t byte_data = edid[kYearOfManufactureOffset];
- if (byte_data >= kValidYearValueLowerBound)
- year_of_manufacture_ = byte_data + kYearOffset;
- }
- // Constants are taken from "VESA Enhanced EDID Standard" Release A, Revision
- // 1, Feb 2000, Sec 3.6 "Basic Display Parameters and Features: 5 bytes"
- static constexpr int kBitsPerChannelTable[] = {0, 6, 8, 10, 12, 14, 16, 0};
- constexpr size_t kEDIDRevisionNumberOffset = 19;
- constexpr uint8_t kEDIDRevision4Value = 4;
- constexpr size_t kVideoInputDefinitionOffset = 20;
- constexpr uint8_t kDigitalInfoMask = 0x80;
- constexpr uint8_t kColorBitDepthMask = 0x70;
- constexpr uint8_t kColorBitDepthOffset = 4;
- if (edid.size() < kVideoInputDefinitionOffset + 1) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kBitsPerChannel);
- return; // Any other fields below are beyond this edid offset.
- }
- if (edid[kEDIDRevisionNumberOffset] >= kEDIDRevision4Value &&
- (edid[kVideoInputDefinitionOffset] & kDigitalInfoMask)) {
- // EDID needs to be revision 4 at least, and kDigitalInfoMask be set for
- // the Video Input Definition entry to describe a digital interface.
- bits_per_channel_ = kBitsPerChannelTable[(
- (edid[kVideoInputDefinitionOffset] & kColorBitDepthMask) >>
- kColorBitDepthOffset)];
- }
- constexpr size_t kEDIDMaxHorizontalImageSizeOffset = 21;
- constexpr size_t kEDIDMaxVerticalImageSizeOffset = 22;
- if (edid.size() < kEDIDMaxVerticalImageSizeOffset + 1) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kPhysicalSize);
- return; // Any other fields below are beyond this edid offset.
- }
- const gfx::Size max_image_size(edid[kEDIDMaxHorizontalImageSizeOffset],
- edid[kEDIDMaxVerticalImageSizeOffset]);
- if (!max_image_size.IsEmpty())
- max_image_size_ = max_image_size;
- // Constants are taken from "VESA Enhanced EDID Standard" Release A, Revision
- // 2, Sep 2006, Sec. 3.6.3 "Display Transfer Characteristics (GAMMA ): 1 Byte"
- constexpr size_t kGammaOffset = 23;
- constexpr double kGammaMultiplier = 100.0;
- constexpr double kGammaBias = 100.0;
- if (edid.size() < kGammaOffset + 1) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kGamma);
- return; // Any other fields below are beyond this edid offset.
- }
- if (edid[kGammaOffset] != 0xFF) {
- // Otherwise the byte at kGammaOffset is 0xFF, gamma is stored elsewhere.
- gamma_ = (edid[kGammaOffset] + kGammaBias) / kGammaMultiplier;
- }
- // Offsets, lengths, positions and masks are taken from [1] (or [2]).
- // [1] http://en.wikipedia.org/wiki/Extended_display_identification_data
- // [2] "VESA Enhanced EDID Standard " Release A, Revision 1, Feb 2000, Sec 3.7
- // "Phosphor or Filter Chromaticity: 10 bytes"
- constexpr size_t kChromaticityOffset = 25;
- constexpr unsigned int kChromaticityLength = 10;
- constexpr size_t kRedGreenLsbOffset = 25;
- constexpr uint8_t kRedxLsbPosition = 6;
- constexpr uint8_t kRedyLsbPosition = 4;
- constexpr uint8_t kGreenxLsbPosition = 2;
- constexpr uint8_t kGreenyLsbPosition = 0;
- constexpr size_t kBlueWhiteLsbOffset = 26;
- constexpr uint8_t kBluexLsbPosition = 6;
- constexpr uint8_t kBlueyLsbPosition = 4;
- constexpr uint8_t kWhitexLsbPosition = 2;
- constexpr uint8_t kWhiteyLsbPosition = 0;
- // All LSBits parts are 2 bits wide.
- constexpr uint8_t kLsbMask = 0x3;
- constexpr size_t kRedxMsbOffset = 27;
- constexpr size_t kRedyMsbOffset = 28;
- constexpr size_t kGreenxMsbOffset = 29;
- constexpr size_t kGreenyMsbOffset = 30;
- constexpr size_t kBluexMsbOffset = 31;
- constexpr size_t kBlueyMsbOffset = 32;
- constexpr size_t kWhitexMsbOffset = 33;
- constexpr size_t kWhiteyMsbOffset = 34;
- static_assert(
- kChromaticityOffset + kChromaticityLength == kWhiteyMsbOffset + 1,
- "EDID Parameter section length error");
- if (edid.size() < kChromaticityOffset + kChromaticityLength) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kChromaticityCoordinates);
- return; // Any other fields below are beyond this edid offset.
- }
- const uint8_t red_green_lsbs = edid[kRedGreenLsbOffset];
- const uint8_t blue_white_lsbs = edid[kBlueWhiteLsbOffset];
- // Recompose the 10b values by appropriately mixing the 8 MSBs and the 2 LSBs,
- // then rescale to 1024;
- primaries_.fRX = ((edid[kRedxMsbOffset] << 2) +
- ((red_green_lsbs >> kRedxLsbPosition) & kLsbMask)) /
- 1024.0f;
- primaries_.fRY = ((edid[kRedyMsbOffset] << 2) +
- ((red_green_lsbs >> kRedyLsbPosition) & kLsbMask)) /
- 1024.0f;
- primaries_.fGX = ((edid[kGreenxMsbOffset] << 2) +
- ((red_green_lsbs >> kGreenxLsbPosition) & kLsbMask)) /
- 1024.0f;
- primaries_.fGY = ((edid[kGreenyMsbOffset] << 2) +
- ((red_green_lsbs >> kGreenyLsbPosition) & kLsbMask)) /
- 1024.0f;
- primaries_.fBX = ((edid[kBluexMsbOffset] << 2) +
- ((blue_white_lsbs >> kBluexLsbPosition) & kLsbMask)) /
- 1024.0f;
- primaries_.fBY = ((edid[kBlueyMsbOffset] << 2) +
- ((blue_white_lsbs >> kBlueyLsbPosition) & kLsbMask)) /
- 1024.0f;
- primaries_.fWX = ((edid[kWhitexMsbOffset] << 2) +
- ((blue_white_lsbs >> kWhitexLsbPosition) & kLsbMask)) /
- 1024.0f;
- primaries_.fWY = ((edid[kWhiteyMsbOffset] << 2) +
- ((blue_white_lsbs >> kWhiteyLsbPosition) & kLsbMask)) /
- 1024.0f;
- // TODO(mcasas): Up to two additional White Point coordinates can be provided
- // in a Display Descriptor. Read them if we are not satisfied with |fWX| or
- // |fWy|. https://crbug.com/771345.
- // See http://en.wikipedia.org/wiki/Extended_display_identification_data
- // for the details of EDID data format. We use the following data:
- // bytes 54-125: four descriptors (18-bytes each) which may contain
- // the display name.
- constexpr size_t kDescriptorOffset = 54;
- constexpr size_t kNumDescriptors = 4;
- constexpr size_t kDescriptorLength = 18;
- // The specifier types.
- constexpr uint8_t kMonitorNameDescriptor = 0xfc;
- constexpr uint8_t kDisplayRangeLimitsDescriptor = 0xfd;
- constexpr uint8_t kMonitorSerialNumberDescriptor = 0xff;
- display_name_.clear();
- for (size_t i = 0; i < kNumDescriptors; ++i) {
- if (edid.size() < kDescriptorOffset + (i + 1) * kDescriptorLength)
- break;
- size_t offset = kDescriptorOffset + i * kDescriptorLength;
- // Detailed Timing Descriptor:
- if (edid[offset] != 0 && edid[offset + 1] != 0) {
- constexpr int kMaxResolution = 10080; // 8k display.
- // EDID may contain multiple DTD. Use the first one, that contains the
- // highest resolution.
- if (active_pixel_size_.IsEmpty()) {
- constexpr size_t kHorizontalPixelLsbOffset = 2;
- constexpr size_t kHorizontalPixelMsbOffset = 4;
- constexpr size_t kVerticalPixelLsbOffset = 5;
- constexpr size_t kVerticalPixelMsbOffset = 7;
- const uint8_t h_lsb = edid[offset + kHorizontalPixelLsbOffset];
- const uint8_t h_msb = edid[offset + kHorizontalPixelMsbOffset];
- int h_pixel = std::min(h_lsb + ((h_msb & 0xF0) << 4), kMaxResolution);
- const uint8_t v_lsb = edid[offset + kVerticalPixelLsbOffset];
- const uint8_t v_msb = edid[offset + kVerticalPixelMsbOffset];
- int v_pixel = std::min(v_lsb + ((v_msb & 0xF0) << 4), kMaxResolution);
- active_pixel_size_.SetSize(h_pixel, v_pixel);
- }
- continue;
- }
- // EDID Other Monitor Descriptors:
- // If the descriptor contains the display name, it has the following
- // structure:
- // bytes 0-2, 4: \0
- // byte 3: 0xfc
- // bytes 5-17: text data, ending with \r, padding with spaces
- // we should check bytes 0-2 and 4, since it may have other values in
- // case that the descriptor contains other type of data.
- if (edid[offset] == 0 && edid[offset + 1] == 0 && edid[offset + 2] == 0 &&
- edid[offset + 3] == kMonitorNameDescriptor && edid[offset + 4] == 0) {
- std::string name(reinterpret_cast<const char*>(&edid[offset + 5]),
- kDescriptorLength - 5);
- base::TrimWhitespaceASCII(name, base::TRIM_TRAILING, &display_name_);
- continue;
- }
- // If the descriptor contains the display's range limits, it has the
- // following structure:
- // bytes 0-2: \0
- // byte 3: 0xfd
- // byte 4: Offsets for display range limits
- // bytes 5-17: Display range limits and timing information
- if (edid[offset] == 0 && edid[offset + 1] == 0 && edid[offset + 2] == 0 &&
- edid[offset + 3] == kDisplayRangeLimitsDescriptor) {
- // byte 4: Offsets for display range limits
- const uint8_t kRateOffset = edid[offset + 4];
- // bits 7-4: Reserved \0
- if (kRateOffset & 0x10)
- continue;
- // bit 3: Horizontal max rate offset (not used)
- // bit 2: Horizontal min rate offset (not used)
- // bit 1: Vertical max rate offset
- const uint8_t verticalMaxRateOffset = kRateOffset & (1 << 1) ? 255 : 0;
- // bit 0: Vertical min rate offset
- const uint8_t verticalMinRateOffset = kRateOffset & (1 << 0) ? 255 : 0;
- // bytes 5-8: Rate limits
- // Each byte must be within [1, 255].
- if (edid[offset + 5] == 0 || edid[offset + 6] == 0 ||
- edid[offset + 7] == 0 || edid[offset + 8] == 0)
- continue;
- // byte 5: Min vertical rate in Hz
- min_vfreq_ = edid[offset + 5] + verticalMinRateOffset;
- // byte 6: Max vertical rate in Hz
- max_vfreq_ = edid[offset + 6] + verticalMaxRateOffset;
- // byte 7: Min horizontal rate in kHz (not used)
- // byte 8: Max horizontal rate in kHz (not used)
- // byte 9: Maximum pixel clock rate (not used)
- // byte 10: Extended timing information type (not used)
- // bytes 11-17: Video timing parameters (not used)
- continue;
- }
- // If the descriptor contains the display's product serial number, it has
- // the following structure:
- // bytes 0-2, 4: \0
- // byte 3: 0xff
- // bytes 5-17: text data, ending with \r, padding with spaces
- // we should check bytes 0-2 and 4, since it may have other values in
- // case that the descriptor contains other type of data.
- if (edid[offset] == 0 && edid[offset + 1] == 0 && edid[offset + 2] == 0 &&
- edid[offset + 3] == kMonitorSerialNumberDescriptor &&
- edid[offset + 4] == 0) {
- std::string serial_number_str(
- reinterpret_cast<const char*>(&edid[offset + 5]),
- kDescriptorLength - 5);
- base::TrimWhitespaceASCII(serial_number_str, base::TRIM_TRAILING,
- &serial_number_str);
- if (!serial_number_str.empty()) {
- descriptor_block_serial_number_hash_ =
- base::MD5String(serial_number_str);
- }
- continue;
- }
- }
- // Verify if the |display_name_| consists of printable characters only.
- // Replace unprintable chars with white space.
- std::replace_if(
- display_name_.begin(), display_name_.end(),
- [](char c) { return !isascii(c) || !isprint(c); }, ' ');
- // See http://en.wikipedia.org/wiki/Extended_display_identification_data
- // for the extension format of EDID. Also see EIA/CEA-861 spec for
- // the format of the extensions and how video capability is encoded.
- // - byte 0: tag. should be 02h.
- // - byte 1: revision. only cares revision 3 (03h).
- // - byte 4-: data block.
- constexpr size_t kExtensionBaseOffset = 128;
- constexpr size_t kExtensionSize = 128;
- constexpr size_t kNumExtensionsOffset = 126;
- constexpr size_t kDataBlockOffset = 4;
- constexpr uint8_t kCEAExtensionTag = '\x02';
- constexpr uint8_t kExpectedExtensionRevision = '\x03';
- constexpr uint8_t kExtendedTag = 7;
- constexpr uint8_t kExtendedVideoCapabilityTag = 0;
- constexpr uint8_t kPTOverscanFlagPosition = 4;
- constexpr uint8_t kITOverscanFlagPosition = 2;
- constexpr uint8_t kCEOverscanFlagPosition = 0;
- // See CTA-861-F, particularly Table 56 "Colorimetry Data Block".
- constexpr uint8_t kColorimetryDataBlockCapabilityTag = 0x05;
- constexpr gfx::ColorSpace::PrimaryID kPrimaryIDMap[] = {
- // xvYCC601. Standard Definition Colorimetry based on IEC 61966-2-4.
- gfx::ColorSpace::PrimaryID::SMPTE170M,
- // xvYCC709. High Definition Colorimetry based on IEC 61966-2-4.
- gfx::ColorSpace::PrimaryID::BT709,
- // sYCC601. Colorimetry based on IEC 61966-2-1/Amendment 1.
- gfx::ColorSpace::PrimaryID::SMPTE170M,
- // opYCC601. Colorimetry based on IEC 61966-2-5, Annex A.
- gfx::ColorSpace::PrimaryID::SMPTE170M,
- // opRGB, Colorimetry based on IEC 61966-2-5.
- gfx::ColorSpace::PrimaryID::SMPTE170M,
- // BT2020RGB. Colorimetry based on ITU-R BT.2020 R’G’B’.
- gfx::ColorSpace::PrimaryID::BT2020,
- // BT2020YCC. Colorimetry based on ITU-R BT.2020 Y’C’BC’R.
- gfx::ColorSpace::PrimaryID::BT2020,
- // BT2020cYCC. Colorimetry based on ITU-R BT.2020 Y’cC’BCC’RC.
- gfx::ColorSpace::PrimaryID::BT2020,
- };
- // See CEA 861.G-2018, Sec.7.5.13, "HDR Static Metadata Data Block" for these.
- constexpr uint8_t kHDRStaticMetadataCapabilityTag = 0x6;
- constexpr gfx::ColorSpace::TransferID kTransferIDMap[] = {
- gfx::ColorSpace::TransferID::BT709,
- gfx::ColorSpace::TransferID::GAMMA24,
- gfx::ColorSpace::TransferID::PQ,
- // STD B67 is also known as Hybrid-log Gamma (HLG).
- gfx::ColorSpace::TransferID::HLG,
- };
- constexpr uint8_t kHDRStaticMetadataDataBlockLengthMask = 0x1F;
- if (edid.size() < kNumExtensionsOffset + 1) {
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kExtensions);
- return; // Any other fields below are beyond this edid offset.
- }
- const uint8_t num_extensions = edid[kNumExtensionsOffset];
- for (size_t i = 0; i < num_extensions; ++i) {
- // Skip parsing the whole extension if size is not enough.
- if (edid.size() < kExtensionBaseOffset + (i + 1) * kExtensionSize)
- break;
- const size_t extension_offset = kExtensionBaseOffset + i * kExtensionSize;
- const uint8_t cea_tag = edid[extension_offset];
- const uint8_t revision = edid[extension_offset + 1];
- if (cea_tag != kCEAExtensionTag || revision != kExpectedExtensionRevision)
- continue;
- const uint8_t timing_descriptors_start = std::min(
- edid[extension_offset + 2], static_cast<unsigned char>(kExtensionSize));
- for (size_t data_offset = extension_offset + kDataBlockOffset;
- data_offset < extension_offset + timing_descriptors_start;) {
- // A data block is encoded as:
- // - byte 1 high 3 bits: tag. '07' for extended tags.
- // - byte 1 remaining bits: the length of data block.
- // - byte 2: the extended tag. E.g. '0' for video capability. Values are
- // defined by the k...CapabilityTag constants.
- // - byte 3: the capability.
- const uint8_t tag = edid[data_offset] >> 5;
- const uint8_t payload_length = edid[data_offset] & 0x1f;
- if (data_offset + payload_length + 1 > edid.size())
- break;
- if (tag != kExtendedTag || payload_length < 2) {
- data_offset += payload_length + 1;
- continue;
- }
- switch (edid[data_offset + 1]) {
- case kExtendedVideoCapabilityTag:
- // The difference between preferred, IT, and CE video formats doesn't
- // matter. Set the flag to true if any of these flags are true.
- overscan_flag_ =
- (edid[data_offset + 2] & (1 << kPTOverscanFlagPosition)) ||
- (edid[data_offset + 2] & (1 << kITOverscanFlagPosition)) ||
- (edid[data_offset + 2] & (1 << kCEOverscanFlagPosition));
- break;
- case kColorimetryDataBlockCapabilityTag: {
- constexpr size_t kMaxNumColorimetryEntries = 8;
- const std::bitset<kMaxNumColorimetryEntries>
- supported_primaries_bitfield(edid[data_offset + 2]);
- static_assert(
- kMaxNumColorimetryEntries == std::size(kPrimaryIDMap),
- "kPrimaryIDMap should describe all possible colorimetry entries");
- for (size_t entry = 0; entry < kMaxNumColorimetryEntries; ++entry) {
- if (supported_primaries_bitfield[entry])
- supported_color_primary_ids_.insert(kPrimaryIDMap[entry]);
- }
- break;
- }
- case kHDRStaticMetadataCapabilityTag: {
- constexpr size_t kMaxNumHDRStaticMedatataEntries = 4;
- const std::bitset<kMaxNumHDRStaticMedatataEntries>
- supported_eotfs_bitfield(edid[data_offset + 2]);
- static_assert(
- kMaxNumHDRStaticMedatataEntries == std::size(kTransferIDMap),
- "kTransferIDMap should describe all possible transfer entries");
- for (size_t entry = 0; entry < kMaxNumHDRStaticMedatataEntries;
- ++entry) {
- if (supported_eotfs_bitfield[entry])
- supported_color_transfer_ids_.insert(kTransferIDMap[entry]);
- }
- // See CEA 861.3-2015, Sec.7.5.13, "HDR Static Metadata Data Block"
- // for details on the following calculations.
- const uint8_t length_of_data_block =
- edid[data_offset] & kHDRStaticMetadataDataBlockLengthMask;
- if (length_of_data_block <= 3)
- break;
- const uint8_t desired_content_max_luminance = edid[data_offset + 4];
- hdr_static_metadata_ =
- absl::make_optional<gfx::HDRStaticMetadata>({});
- hdr_static_metadata_->max =
- 50.0 * pow(2, desired_content_max_luminance / 32.0);
- if (length_of_data_block <= 4)
- break;
- const uint8_t desired_content_max_frame_average_luminance =
- edid[data_offset + 5];
- hdr_static_metadata_->max_avg =
- 50.0 * pow(2, desired_content_max_frame_average_luminance / 32.0);
- if (length_of_data_block <= 5)
- break;
- const uint8_t desired_content_min_luminance = edid[data_offset + 6];
- hdr_static_metadata_->min =
- hdr_static_metadata_->max *
- pow(desired_content_min_luminance / 255.0, 2) / 100.0;
- break;
- }
- default:
- break;
- }
- data_offset += payload_length + 1;
- }
- }
- base::UmaHistogramEnumeration(kParseEdidFailureMetric,
- ParseEdidFailure::kNoError);
- ReportEdidOptionalsForExternalDisplay();
- }
- void EdidParser::ReportEdidOptionalsForExternalDisplay() const {
- if (!is_external_display_)
- return;
- bool all_optionals_available = true;
- if (!week_of_manufacture_.has_value()) {
- all_optionals_available = false;
- base::UmaHistogramEnumeration(kParseExternalDisplayEdidOptionalsMetric,
- ParseEdidOptionals::kWeekOfManufacture);
- }
- if (!max_image_size_.has_value()) {
- all_optionals_available = false;
- base::UmaHistogramEnumeration(kParseExternalDisplayEdidOptionalsMetric,
- ParseEdidOptionals::kPhysicalSize);
- }
- uint8_t serial_number_count = kMaxSerialNumberCount;
- if (!block_zero_serial_number_hash_.has_value()) {
- all_optionals_available = false;
- serial_number_count--;
- base::UmaHistogramEnumeration(kParseExternalDisplayEdidOptionalsMetric,
- ParseEdidOptionals::kBlockZeroSerialNumber);
- }
- if (!descriptor_block_serial_number_hash_.has_value()) {
- all_optionals_available = false;
- serial_number_count--;
- base::UmaHistogramEnumeration(
- kParseExternalDisplayEdidOptionalsMetric,
- ParseEdidOptionals::kDescriptorBlockSerialNumber);
- }
- base::UmaHistogramExactLinear(kNumOfSerialNumbersProvidedByExternalDisplay,
- serial_number_count, kMaxSerialNumberCount);
- if (all_optionals_available) {
- base::UmaHistogramEnumeration(kParseExternalDisplayEdidOptionalsMetric,
- ParseEdidOptionals::kAllAvailable);
- }
- }
- } // namespace display
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