SF: parsing Detailed Timing Descriptor in the framework
The first DTD in an edid is the preferred timing which allows to get
a more precise and more often correct physical size for a display. This
can be used to estimate or correct the dpi in case the edid reports the
wrong size and hwc is not providing the right value.
See edid spec: https://glenwing.github.io/docs/VESA-EEDID-A2.pdf
Flag: com.android.graphics.surfaceflinger.flags.correct_dpi_with_display_size
Bug: 361413340
Test: DisplayIdentification_test
Test: HWComposerTest
Test: manual - see bug and doc
Change-Id: I0bb85dcf8039f923f1ac892c4a1d6bda771dbf4f
diff --git a/libs/ui/DisplayIdentification.cpp b/libs/ui/DisplayIdentification.cpp
index e5af740..8b13d78 100644
--- a/libs/ui/DisplayIdentification.cpp
+++ b/libs/ui/DisplayIdentification.cpp
@@ -26,6 +26,7 @@
#include <ftl/hash.h>
#include <log/log.h>
#include <ui/DisplayIdentification.h>
+#include <ui/Size.h>
namespace android {
namespace {
@@ -46,6 +47,10 @@
return view[3];
}
+bool isDetailedTimingDescriptor(const byte_view& view) {
+ return view[0] != 0 && view[1] != 0;
+}
+
std::string_view parseEdidText(const byte_view& view) {
std::string_view text(reinterpret_cast<const char*>(view.data()), view.size());
text = text.substr(0, text.find('\n'));
@@ -219,6 +224,8 @@
std::string_view displayName;
std::string_view serialNumber;
std::string_view asciiText;
+ ui::Size preferredDTDPixelSize;
+ ui::Size preferredDTDPhysicalSize;
constexpr size_t kDescriptorCount = 4;
constexpr size_t kDescriptorLength = 18;
@@ -243,6 +250,35 @@
serialNumber = parseEdidText(descriptor);
break;
}
+ } else if (isDetailedTimingDescriptor(view)) {
+ static constexpr size_t kHorizontalPhysicalLsbOffset = 12;
+ static constexpr size_t kHorizontalPhysicalMsbOffset = 14;
+ static constexpr size_t kVerticalPhysicalLsbOffset = 13;
+ static constexpr size_t kVerticalPhysicalMsbOffset = 14;
+ const uint32_t hSize =
+ static_cast<uint32_t>(view[kHorizontalPhysicalLsbOffset] |
+ ((view[kHorizontalPhysicalMsbOffset] >> 4) << 8));
+ const uint32_t vSize =
+ static_cast<uint32_t>(view[kVerticalPhysicalLsbOffset] |
+ ((view[kVerticalPhysicalMsbOffset] & 0b1111) << 8));
+
+ static constexpr size_t kHorizontalPixelLsbOffset = 2;
+ static constexpr size_t kHorizontalPixelMsbOffset = 4;
+ static constexpr size_t kVerticalPixelLsbOffset = 5;
+ static constexpr size_t kVerticalPixelMsbOffset = 7;
+
+ const uint8_t hLsb = view[kHorizontalPixelLsbOffset];
+ const uint8_t hMsb = view[kHorizontalPixelMsbOffset];
+ const int32_t hPixel = hLsb + ((hMsb & 0xF0) << 4);
+
+ const uint8_t vLsb = view[kVerticalPixelLsbOffset];
+ const uint8_t vMsb = view[kVerticalPixelMsbOffset];
+ const int32_t vPixel = vLsb + ((vMsb & 0xF0) << 4);
+
+ preferredDTDPixelSize.setWidth(hPixel);
+ preferredDTDPixelSize.setHeight(vPixel);
+ preferredDTDPhysicalSize.setWidth(hSize);
+ preferredDTDPhysicalSize.setHeight(vSize);
}
view = view.subspan(kDescriptorLength);
@@ -297,14 +333,22 @@
}
}
- return Edid{.manufacturerId = manufacturerId,
- .productId = productId,
- .pnpId = *pnpId,
- .modelHash = modelHash,
- .displayName = displayName,
- .manufactureOrModelYear = manufactureOrModelYear,
- .manufactureWeek = manufactureWeek,
- .cea861Block = cea861Block};
+ DetailedTimingDescriptor preferredDetailedTimingDescriptor{
+ .pixelSizeCount = preferredDTDPixelSize,
+ .physicalSizeInMm = preferredDTDPhysicalSize,
+ };
+
+ return Edid{
+ .manufacturerId = manufacturerId,
+ .productId = productId,
+ .pnpId = *pnpId,
+ .modelHash = modelHash,
+ .displayName = displayName,
+ .manufactureOrModelYear = manufactureOrModelYear,
+ .manufactureWeek = manufactureWeek,
+ .cea861Block = cea861Block,
+ .preferredDetailedTimingDescriptor = preferredDetailedTimingDescriptor,
+ };
}
std::optional<PnpId> getPnpId(uint16_t manufacturerId) {
@@ -336,9 +380,12 @@
}
const auto displayId = PhysicalDisplayId::fromEdid(port, edid->manufacturerId, edid->modelHash);
- return DisplayIdentificationInfo{.id = displayId,
- .name = std::string(edid->displayName),
- .deviceProductInfo = buildDeviceProductInfo(*edid)};
+ return DisplayIdentificationInfo{
+ .id = displayId,
+ .name = std::string(edid->displayName),
+ .deviceProductInfo = buildDeviceProductInfo(*edid),
+ .preferredDetailedTimingDescriptor = edid->preferredDetailedTimingDescriptor,
+ };
}
PhysicalDisplayId getVirtualDisplayId(uint32_t id) {
diff --git a/libs/ui/include/ui/DisplayIdentification.h b/libs/ui/include/ui/DisplayIdentification.h
index 8bc2017..648e024 100644
--- a/libs/ui/include/ui/DisplayIdentification.h
+++ b/libs/ui/include/ui/DisplayIdentification.h
@@ -25,6 +25,7 @@
#include <ui/DeviceProductInfo.h>
#include <ui/DisplayId.h>
+#include <ui/Size.h>
#define LEGACY_DISPLAY_TYPE_PRIMARY 0
#define LEGACY_DISPLAY_TYPE_EXTERNAL 1
@@ -33,10 +34,16 @@
using DisplayIdentificationData = std::vector<uint8_t>;
+struct DetailedTimingDescriptor {
+ ui::Size pixelSizeCount;
+ ui::Size physicalSizeInMm;
+};
+
struct DisplayIdentificationInfo {
PhysicalDisplayId id;
std::string name;
std::optional<DeviceProductInfo> deviceProductInfo;
+ std::optional<DetailedTimingDescriptor> preferredDetailedTimingDescriptor;
};
struct ExtensionBlock {
@@ -68,6 +75,7 @@
uint8_t manufactureOrModelYear;
uint8_t manufactureWeek;
std::optional<Cea861ExtensionBlock> cea861Block;
+ std::optional<DetailedTimingDescriptor> preferredDetailedTimingDescriptor;
};
bool isEdid(const DisplayIdentificationData&);
diff --git a/libs/ui/tests/DisplayIdentification_test.cpp b/libs/ui/tests/DisplayIdentification_test.cpp
index 721b466..76e3f66 100644
--- a/libs/ui/tests/DisplayIdentification_test.cpp
+++ b/libs/ui/tests/DisplayIdentification_test.cpp
@@ -194,6 +194,10 @@
EXPECT_EQ(21, edid->manufactureOrModelYear);
EXPECT_EQ(0, edid->manufactureWeek);
EXPECT_FALSE(edid->cea861Block);
+ EXPECT_EQ(1280, edid->preferredDetailedTimingDescriptor->pixelSizeCount.width);
+ EXPECT_EQ(800, edid->preferredDetailedTimingDescriptor->pixelSizeCount.height);
+ EXPECT_EQ(261, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.width);
+ EXPECT_EQ(163, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.height);
edid = parseEdid(getExternalEdid());
ASSERT_TRUE(edid);
@@ -206,6 +210,10 @@
EXPECT_EQ(22, edid->manufactureOrModelYear);
EXPECT_EQ(2, edid->manufactureWeek);
EXPECT_FALSE(edid->cea861Block);
+ EXPECT_EQ(1280, edid->preferredDetailedTimingDescriptor->pixelSizeCount.width);
+ EXPECT_EQ(800, edid->preferredDetailedTimingDescriptor->pixelSizeCount.height);
+ EXPECT_EQ(641, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.width);
+ EXPECT_EQ(400, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.height);
edid = parseEdid(getExternalEedid());
ASSERT_TRUE(edid);
@@ -224,6 +232,10 @@
EXPECT_EQ(0, physicalAddress.b);
EXPECT_EQ(0, physicalAddress.c);
EXPECT_EQ(0, physicalAddress.d);
+ EXPECT_EQ(1366, edid->preferredDetailedTimingDescriptor->pixelSizeCount.width);
+ EXPECT_EQ(768, edid->preferredDetailedTimingDescriptor->pixelSizeCount.height);
+ EXPECT_EQ(160, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.width);
+ EXPECT_EQ(90, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.height);
edid = parseEdid(getPanasonicTvEdid());
ASSERT_TRUE(edid);
@@ -242,6 +254,10 @@
EXPECT_EQ(0, physicalAddress.b);
EXPECT_EQ(0, physicalAddress.c);
EXPECT_EQ(0, physicalAddress.d);
+ EXPECT_EQ(1920, edid->preferredDetailedTimingDescriptor->pixelSizeCount.width);
+ EXPECT_EQ(1080, edid->preferredDetailedTimingDescriptor->pixelSizeCount.height);
+ EXPECT_EQ(698, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.width);
+ EXPECT_EQ(392, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.height);
edid = parseEdid(getHisenseTvEdid());
ASSERT_TRUE(edid);
@@ -260,6 +276,10 @@
EXPECT_EQ(2, physicalAddress.b);
EXPECT_EQ(3, physicalAddress.c);
EXPECT_EQ(4, physicalAddress.d);
+ EXPECT_EQ(1920, edid->preferredDetailedTimingDescriptor->pixelSizeCount.width);
+ EXPECT_EQ(1080, edid->preferredDetailedTimingDescriptor->pixelSizeCount.height);
+ EXPECT_EQ(575, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.width);
+ EXPECT_EQ(323, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.height);
edid = parseEdid(getCtlDisplayEdid());
ASSERT_TRUE(edid);
@@ -273,6 +293,10 @@
EXPECT_EQ(0xff, edid->manufactureWeek);
ASSERT_TRUE(edid->cea861Block);
EXPECT_FALSE(edid->cea861Block->hdmiVendorDataBlock);
+ EXPECT_EQ(1360, edid->preferredDetailedTimingDescriptor->pixelSizeCount.width);
+ EXPECT_EQ(768, edid->preferredDetailedTimingDescriptor->pixelSizeCount.height);
+ EXPECT_EQ(521, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.width);
+ EXPECT_EQ(293, edid->preferredDetailedTimingDescriptor->physicalSizeInMm.height);
}
TEST(DisplayIdentificationTest, parseInvalidEdid) {