SF: Parse HDMI Physical Address from EDID.
This CL parses HDMI Physical Address from the HDMI Vendor
Specific Data Block in the EDID of the connected display.
This information will be later added to the DeviceProductInfo
structure.
Bug: 147994746
Test: atest DisplayIdentificationTest
Change-Id: I5098f488b3cbf0b40896c837d24d2d29aa985431
diff --git a/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp b/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
index 63897cc..f9281a7 100644
--- a/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
+++ b/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
@@ -35,6 +35,7 @@
using byte_view = std::basic_string_view<uint8_t>;
+constexpr size_t kEdidBlockSize = 128;
constexpr size_t kEdidHeaderLength = 5;
constexpr uint16_t kFallbackEdidManufacturerId = 0;
@@ -94,6 +95,57 @@
return info;
}
+Cea861ExtensionBlock parseCea861Block(const byte_view& block) {
+ Cea861ExtensionBlock cea861Block;
+
+ constexpr size_t kRevisionNumberOffset = 1;
+ cea861Block.revisionNumber = block[kRevisionNumberOffset];
+
+ constexpr size_t kDetailedTimingDescriptorsOffset = 2;
+ const size_t dtdStart =
+ std::min(kEdidBlockSize, static_cast<size_t>(block[kDetailedTimingDescriptorsOffset]));
+
+ // Parse data blocks.
+ for (size_t dataBlockOffset = 4; dataBlockOffset < dtdStart;) {
+ const uint8_t header = block[dataBlockOffset];
+ const uint8_t tag = header >> 5;
+ const size_t bodyLength = header & 0b11111;
+ constexpr size_t kDataBlockHeaderSize = 1;
+ const size_t dataBlockSize = bodyLength + kDataBlockHeaderSize;
+
+ if (block.size() < dataBlockOffset + dataBlockSize) {
+ ALOGW("Invalid EDID: CEA 861 data block is truncated.");
+ break;
+ }
+
+ const byte_view dataBlock(block.data() + dataBlockOffset, dataBlockSize);
+ constexpr uint8_t kVendorSpecificDataBlockTag = 0x3;
+
+ if (tag == kVendorSpecificDataBlockTag) {
+ const uint32_t ieeeRegistrationId =
+ dataBlock[1] | (dataBlock[2] << 8) | (dataBlock[3] << 16);
+ constexpr uint32_t kHdmiIeeeRegistrationId = 0xc03;
+
+ if (ieeeRegistrationId == kHdmiIeeeRegistrationId) {
+ const uint8_t a = dataBlock[4] >> 4;
+ const uint8_t b = dataBlock[4] & 0b1111;
+ const uint8_t c = dataBlock[5] >> 4;
+ const uint8_t d = dataBlock[5] & 0b1111;
+ cea861Block.hdmiVendorDataBlock =
+ HdmiVendorDataBlock{.physicalAddress = HdmiPhysicalAddress{a, b, c, d}};
+ } else {
+ ALOGV("Ignoring vendor specific data block for vendor with IEEE OUI %x",
+ ieeeRegistrationId);
+ }
+ } else {
+ ALOGV("Ignoring CEA-861 data block with tag %x", tag);
+ }
+ dataBlockOffset += bodyLength + kDataBlockHeaderSize;
+ }
+
+ return cea861Block;
+}
+
} // namespace
uint16_t DisplayId::manufacturerId() const {
@@ -111,13 +163,12 @@
}
std::optional<Edid> parseEdid(const DisplayIdentificationData& edid) {
- constexpr size_t kMinLength = 128;
- if (edid.size() < kMinLength) {
+ if (edid.size() < kEdidBlockSize) {
ALOGW("Invalid EDID: structure is truncated.");
// Attempt parsing even if EDID is malformed.
} else {
- ALOGW_IF(edid[126] != 0, "EDID extensions are currently unsupported.");
- ALOGW_IF(std::accumulate(edid.begin(), edid.begin() + kMinLength, static_cast<uint8_t>(0)),
+ ALOGW_IF(std::accumulate(edid.begin(), edid.begin() + kEdidBlockSize,
+ static_cast<uint8_t>(0)),
"Invalid EDID: structure does not checksum.");
}
@@ -222,13 +273,43 @@
// have been observed to change on some displays with multiple inputs.
const auto modelHash = static_cast<uint32_t>(std::hash<std::string_view>()(modelString));
+ // Parse extension blocks.
+ std::optional<Cea861ExtensionBlock> cea861Block;
+ if (edid.size() < kEdidBlockSize) {
+ ALOGW("Invalid EDID: block 0 is truncated.");
+ } else {
+ constexpr size_t kNumExtensionsOffset = 126;
+ const size_t numExtensions = edid[kNumExtensionsOffset];
+ view = byte_view(edid.data(), edid.size());
+ for (size_t blockNumber = 1; blockNumber <= numExtensions; blockNumber++) {
+ view.remove_prefix(kEdidBlockSize);
+ if (view.size() < kEdidBlockSize) {
+ ALOGW("Invalid EDID: block %zu is truncated.", blockNumber);
+ break;
+ }
+
+ const byte_view block(view.data(), kEdidBlockSize);
+ ALOGW_IF(std::accumulate(block.begin(), block.end(), static_cast<uint8_t>(0)),
+ "Invalid EDID: block %zu does not checksum.", blockNumber);
+ const uint8_t tag = block[0];
+
+ constexpr uint8_t kCea861BlockTag = 0x2;
+ if (tag == kCea861BlockTag) {
+ cea861Block = parseCea861Block(block);
+ } else {
+ ALOGV("Ignoring block number %zu with tag %x.", blockNumber, tag);
+ }
+ }
+ }
+
return Edid{.manufacturerId = manufacturerId,
.productId = productId,
.pnpId = *pnpId,
.modelHash = modelHash,
.displayName = displayName,
+ .manufactureOrModelYear = manufactureOrModelYear,
.manufactureWeek = manufactureWeek,
- .manufactureOrModelYear = manufactureOrModelYear};
+ .cea861Block = cea861Block};
}
std::optional<PnpId> getPnpId(uint16_t manufacturerId) {