commit 8d0a0c43c1416e8540b0adf527be2ec5c69cccff
author Lucas Berthou <berlu@google.com> Tue Aug 27 14:32:31 2024 +0000
committer Lucas Berthou <berlu@google.com> Thu Sep 12 15:34:14 2024 +0000
tree 682fb7f95b794e517bc233658a1138930bae3728
parent 5b0bdd2cd9b9920679fd530b8b136559d5441343

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

services/surfaceflinger/tests/unittests/HWComposerTest.cpp

diff --git a/services/surfaceflinger/tests/unittests/HWComposerTest.cpp b/services/surfaceflinger/tests/unittests/HWComposerTest.cpp
index 6030427..e0753a3 100644
--- a/services/surfaceflinger/tests/unittests/HWComposerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/HWComposerTest.cpp
@@ -166,6 +166,7 @@
     expectHotplugConnect(kHwcDisplayId);
     const auto info = mHwc.onHotplug(kHwcDisplayId, hal::Connection::CONNECTED);
     ASSERT_TRUE(info);
+    ASSERT_TRUE(info->preferredDetailedTimingDescriptor.has_value());
 
     EXPECT_CALL(*mHal, isVrrSupported()).WillRepeatedly(Return(false));
 
@@ -179,6 +180,10 @@
         constexpr int32_t kHeight = 720;
         constexpr int32_t kConfigGroup = 1;
         constexpr int32_t kVsyncPeriod = 16666667;
+        constexpr float kMmPerInch = 25.4f;
+        const ui::Size size = info->preferredDetailedTimingDescriptor->physicalSizeInMm;
+        const float expectedDpiX = (kWidth * kMmPerInch / size.width);
+        const float expectedDpiY = (kHeight * kMmPerInch / size.height);
 
         EXPECT_CALL(*mHal,
                     getDisplayAttribute(kHwcDisplayId, kConfigId, IComposerClient::Attribute::WIDTH,
@@ -218,8 +223,13 @@
         EXPECT_EQ(modes.front().height, kHeight);
         EXPECT_EQ(modes.front().configGroup, kConfigGroup);
         EXPECT_EQ(modes.front().vsyncPeriod, kVsyncPeriod);
-        EXPECT_EQ(modes.front().dpiX, -1);
-        EXPECT_EQ(modes.front().dpiY, -1);
+        if (!FlagManager::getInstance().correct_dpi_with_display_size()) {
+            EXPECT_EQ(modes.front().dpiX, -1);
+            EXPECT_EQ(modes.front().dpiY, -1);
+        } else {
+            EXPECT_EQ(modes.front().dpiX, expectedDpiX);
+            EXPECT_EQ(modes.front().dpiY, expectedDpiY);
+        }
 
         // Optional parameters are supported
         constexpr int32_t kDpi = 320;
@@ -271,6 +281,10 @@
         constexpr int32_t kHeight = 720;
         constexpr int32_t kConfigGroup = 1;
         constexpr int32_t kVsyncPeriod = 16666667;
+        constexpr float kMmPerInch = 25.4f;
+        const ui::Size size = info->preferredDetailedTimingDescriptor->physicalSizeInMm;
+        const float expectedDpiX = (kWidth * kMmPerInch / size.width);
+        const float expectedDpiY = (kHeight * kMmPerInch / size.height);
 
         EXPECT_CALL(*mHal,
                     getDisplayAttribute(kHwcDisplayId, kConfigId, IComposerClient::Attribute::WIDTH,
@@ -310,8 +324,13 @@
         EXPECT_EQ(modes.front().height, kHeight);
         EXPECT_EQ(modes.front().configGroup, kConfigGroup);
         EXPECT_EQ(modes.front().vsyncPeriod, kVsyncPeriod);
-        EXPECT_EQ(modes.front().dpiX, -1);
-        EXPECT_EQ(modes.front().dpiY, -1);
+        if (!FlagManager::getInstance().correct_dpi_with_display_size()) {
+            EXPECT_EQ(modes.front().dpiX, -1);
+            EXPECT_EQ(modes.front().dpiY, -1);
+        } else {
+            EXPECT_EQ(modes.front().dpiX, expectedDpiX);
+            EXPECT_EQ(modes.front().dpiY, expectedDpiY);
+        }
 
         // Optional parameters are supported
         constexpr int32_t kDpi = 320;
@@ -361,6 +380,10 @@
         constexpr int32_t kHeight = 720;
         constexpr int32_t kConfigGroup = 1;
         constexpr int32_t kVsyncPeriod = 16666667;
+        constexpr float kMmPerInch = 25.4f;
+        const ui::Size size = info->preferredDetailedTimingDescriptor->physicalSizeInMm;
+        const float expectedDpiX = (kWidth * kMmPerInch / size.width);
+        const float expectedDpiY = (kHeight * kMmPerInch / size.height);
         const hal::VrrConfig vrrConfig =
                 hal::VrrConfig{.minFrameIntervalNs = static_cast<Fps>(120_Hz).getPeriodNsecs(),
                                .notifyExpectedPresentConfig = hal::VrrConfig::
@@ -387,8 +410,13 @@
         EXPECT_EQ(modes.front().configGroup, kConfigGroup);
         EXPECT_EQ(modes.front().vsyncPeriod, kVsyncPeriod);
         EXPECT_EQ(modes.front().vrrConfig, vrrConfig);
-        EXPECT_EQ(modes.front().dpiX, -1);
-        EXPECT_EQ(modes.front().dpiY, -1);
+        if (!FlagManager::getInstance().correct_dpi_with_display_size()) {
+            EXPECT_EQ(modes.front().dpiX, -1);
+            EXPECT_EQ(modes.front().dpiY, -1);
+        } else {
+            EXPECT_EQ(modes.front().dpiX, expectedDpiX);
+            EXPECT_EQ(modes.front().dpiY, expectedDpiY);
+        }
 
         // Supports optional dpi parameter
         constexpr int32_t kDpi = 320;