SF: Confine display serial number to EDID parser
The EDID parser falls back to the serial number if the display name is
missing. Previously, this string was only used to compute a hash for
display ID encoding, but is now propagated through DeviceProductInfo.
Though DeviceProductInfo is currently a hidden API, stop exposing the
serial number in the first place to avoid inadvertently leaking it.
Bug: 138677816
Test: libsurfaceflinger_unittest
Change-Id: I13f4e7f4d0e9e90866b74ac33a048e8809158a43
diff --git a/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp b/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
index 9aaef65..f24f314 100644
--- a/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
+++ b/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
@@ -104,9 +104,8 @@
return static_cast<uint16_t>(value >> 40);
}
-DisplayId DisplayId::fromEdid(uint8_t port, uint16_t manufacturerId, uint32_t displayNameHash) {
- return {(static_cast<Type>(manufacturerId) << 40) | (static_cast<Type>(displayNameHash) << 8) |
- port};
+DisplayId DisplayId::fromEdid(uint8_t port, uint16_t manufacturerId, uint32_t modelHash) {
+ return {(static_cast<Type>(manufacturerId) << 40) | (static_cast<Type>(modelHash) << 8) | port};
}
bool isEdid(const DisplayIdentificationData& data) {
@@ -209,23 +208,30 @@
view.remove_prefix(kDescriptorLength);
}
- if (displayName.empty()) {
+ std::string_view modelString = displayName;
+
+ if (modelString.empty()) {
ALOGW("Invalid EDID: falling back to serial number due to missing display name.");
- displayName = serialNumber;
+ modelString = serialNumber;
}
- if (displayName.empty()) {
+ if (modelString.empty()) {
ALOGW("Invalid EDID: falling back to ASCII text due to missing serial number.");
- displayName = asciiText;
+ modelString = asciiText;
}
- if (displayName.empty()) {
+ if (modelString.empty()) {
ALOGE("Invalid EDID: display name and fallback descriptors are missing.");
return {};
}
+ // Hash model string instead of using product code or (integer) serial number, since the latter
+ // have been observed to change on some displays with multiple inputs.
+ const auto modelHash = static_cast<uint32_t>(std::hash<std::string_view>()(modelString));
+
return Edid{.manufacturerId = manufacturerId,
- .pnpId = *pnpId,
- .displayName = displayName,
.productId = productId,
+ .pnpId = *pnpId,
+ .modelHash = modelHash,
+ .displayName = displayName,
.manufactureWeek = manufactureWeek,
.manufactureOrModelYear = manufactureOrModelYear};
}
@@ -253,10 +259,8 @@
return {};
}
- // Hash display name instead of using product code or serial number, since the latter have been
- // observed to change on some displays with multiple inputs.
- const auto hash = static_cast<uint32_t>(std::hash<std::string_view>()(edid->displayName));
- return DisplayIdentificationInfo{.id = DisplayId::fromEdid(port, edid->manufacturerId, hash),
+ const auto displayId = DisplayId::fromEdid(port, edid->manufacturerId, edid->modelHash);
+ return DisplayIdentificationInfo{.id = displayId,
.name = std::string(edid->displayName),
.deviceProductInfo = buildDeviceProductInfo(*edid)};
}
diff --git a/services/surfaceflinger/DisplayHardware/DisplayIdentification.h b/services/surfaceflinger/DisplayHardware/DisplayIdentification.h
index 0a18ba1..d91b957 100644
--- a/services/surfaceflinger/DisplayHardware/DisplayIdentification.h
+++ b/services/surfaceflinger/DisplayHardware/DisplayIdentification.h
@@ -34,7 +34,7 @@
uint16_t manufacturerId() const;
- static DisplayId fromEdid(uint8_t port, uint16_t manufacturerId, uint32_t displayNameHash);
+ static DisplayId fromEdid(uint8_t port, uint16_t manufacturerId, uint32_t modelHash);
};
inline bool operator==(DisplayId lhs, DisplayId rhs) {
@@ -61,6 +61,7 @@
uint16_t manufacturerId;
uint16_t productId;
PnpId pnpId;
+ uint32_t modelHash;
std::string_view displayName;
uint8_t manufactureOrModelYear;
uint8_t manufactureWeek;
diff --git a/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp b/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp
index a023367..c2ddfce 100644
--- a/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp
+++ b/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp
@@ -14,6 +14,9 @@
* limitations under the License.
*/
+#include <functional>
+#include <string_view>
+
#include <gmock/gmock.h>
#include <gtest/gtest.h>
@@ -124,6 +127,10 @@
return DisplayIdentificationData(bytes, bytes + N - 1);
}
+uint32_t hash(const char* str) {
+ return static_cast<uint32_t>(std::hash<std::string_view>()(str));
+}
+
} // namespace
const DisplayIdentificationData& getInternalEdid() {
@@ -173,7 +180,8 @@
EXPECT_EQ(0x4ca3u, edid->manufacturerId);
EXPECT_STREQ("SEC", edid->pnpId.data());
// ASCII text should be used as fallback if display name and serial number are missing.
- EXPECT_EQ("121AT11-801", edid->displayName);
+ EXPECT_EQ(hash("121AT11-801"), edid->modelHash);
+ EXPECT_TRUE(edid->displayName.empty());
EXPECT_EQ(12610, edid->productId);
EXPECT_EQ(21, edid->manufactureOrModelYear);
EXPECT_EQ(0, edid->manufactureWeek);
@@ -182,6 +190,7 @@
ASSERT_TRUE(edid);
EXPECT_EQ(0x22f0u, edid->manufacturerId);
EXPECT_STREQ("HWP", edid->pnpId.data());
+ EXPECT_EQ(hash("HP ZR30w"), edid->modelHash);
EXPECT_EQ("HP ZR30w", edid->displayName);
EXPECT_EQ(10348, edid->productId);
EXPECT_EQ(22, edid->manufactureOrModelYear);
@@ -191,6 +200,7 @@
ASSERT_TRUE(edid);
EXPECT_EQ(0x4c2du, edid->manufacturerId);
EXPECT_STREQ("SAM", edid->pnpId.data());
+ EXPECT_EQ(hash("SAMSUNG"), edid->modelHash);
EXPECT_EQ("SAMSUNG", edid->displayName);
EXPECT_EQ(2302, edid->productId);
EXPECT_EQ(21, edid->manufactureOrModelYear);
@@ -200,6 +210,7 @@
ASSERT_TRUE(edid);
EXPECT_EQ(13481, edid->manufacturerId);
EXPECT_STREQ("MEI", edid->pnpId.data());
+ EXPECT_EQ(hash("Panasonic-TV"), edid->modelHash);
EXPECT_EQ("Panasonic-TV", edid->displayName);
EXPECT_EQ(41622, edid->productId);
EXPECT_EQ(29, edid->manufactureOrModelYear);
@@ -209,6 +220,7 @@
ASSERT_TRUE(edid);
EXPECT_EQ(8355, edid->manufacturerId);
EXPECT_STREQ("HEC", edid->pnpId.data());
+ EXPECT_EQ(hash("Hisense"), edid->modelHash);
EXPECT_EQ("Hisense", edid->displayName);
EXPECT_EQ(0, edid->productId);
EXPECT_EQ(29, edid->manufactureOrModelYear);
@@ -218,6 +230,7 @@
ASSERT_TRUE(edid);
EXPECT_EQ(3724, edid->manufacturerId);
EXPECT_STREQ("CTL", edid->pnpId.data());
+ EXPECT_EQ(hash("LP2361"), edid->modelHash);
EXPECT_EQ("LP2361", edid->displayName);
EXPECT_EQ(9373, edid->productId);
EXPECT_EQ(23, edid->manufactureOrModelYear);
@@ -234,13 +247,15 @@
auto edid = parseEdid(data);
ASSERT_TRUE(edid);
// Serial number should be used as fallback if display name is invalid.
- EXPECT_EQ("CN4202137Q", edid->displayName);
+ const auto modelHash = hash("CN4202137Q");
+ EXPECT_EQ(modelHash, edid->modelHash);
+ EXPECT_TRUE(edid->displayName.empty());
// Parsing should succeed even if EDID is truncated.
data.pop_back();
edid = parseEdid(data);
ASSERT_TRUE(edid);
- EXPECT_EQ("CN4202137Q", edid->displayName);
+ EXPECT_EQ(modelHash, edid->modelHash);
}
TEST(DisplayIdentificationTest, getPnpId) {
@@ -278,7 +293,7 @@
ASSERT_TRUE(displayIdInfo);
ASSERT_TRUE(displayIdInfo->deviceProductInfo);
const auto& info = *displayIdInfo->deviceProductInfo;
- EXPECT_STREQ("121AT11-801", info.name.data());
+ EXPECT_STREQ("", info.name.data());
EXPECT_STREQ("SEC", info.manufacturerPnpId.data());
EXPECT_STREQ("12610", info.productId.data());
ASSERT_TRUE(std::holds_alternative<ManufactureYear>(info.manufactureOrModelDate));