diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index 8e78af4..f1fa938 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -675,6 +675,11 @@
         }
     });
 }
+
+void Display::setPhysicalSizeInMm(std::optional<ui::Size> size) {
+    mPhysicalSize = size;
+}
+
 } // namespace impl
 
 // Layer methods
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.h b/services/surfaceflinger/DisplayHardware/HWC2.h
index d426bca..8e2aeaf 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.h
+++ b/services/surfaceflinger/DisplayHardware/HWC2.h
@@ -105,6 +105,7 @@
     virtual bool isVsyncPeriodSwitchSupported() const = 0;
     virtual bool hasDisplayIdleTimerCapability() const = 0;
     virtual void onLayerDestroyed(hal::HWLayerId layerId) = 0;
+    virtual std::optional<ui::Size> getPhysicalSizeInMm() const = 0;
 
     [[nodiscard]] virtual hal::Error acceptChanges() = 0;
     [[nodiscard]] virtual base::expected<std::shared_ptr<HWC2::Layer>, hal::Error>
@@ -285,6 +286,8 @@
     bool hasDisplayIdleTimerCapability() const override;
     void onLayerDestroyed(hal::HWLayerId layerId) override;
     hal::Error getPhysicalDisplayOrientation(Hwc2::AidlTransform* outTransform) const override;
+    void setPhysicalSizeInMm(std::optional<ui::Size> size);
+    std::optional<ui::Size> getPhysicalSizeInMm() const override { return mPhysicalSize; }
 
 private:
     void loadDisplayCapabilities();
@@ -318,6 +321,8 @@
     std::optional<
             std::unordered_set<aidl::android::hardware::graphics::composer3::DisplayCapability>>
             mDisplayCapabilities GUARDED_BY(mDisplayCapabilitiesMutex);
+    // Physical size in mm.
+    std::optional<ui::Size> mPhysicalSize;
 };
 
 } // namespace impl
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index c83e0da..bd093f5 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -76,6 +76,7 @@
 using aidl::android::hardware::graphics::common::HdrConversionStrategy;
 using aidl::android::hardware::graphics::composer3::Capability;
 using aidl::android::hardware::graphics::composer3::DisplayCapability;
+using aidl::android::hardware::graphics::composer3::DisplayConfiguration;
 using namespace std::string_literals;
 
 namespace android {
@@ -222,8 +223,8 @@
     return true;
 }
 
-void HWComposer::allocatePhysicalDisplay(hal::HWDisplayId hwcDisplayId,
-                                         PhysicalDisplayId displayId) {
+void HWComposer::allocatePhysicalDisplay(hal::HWDisplayId hwcDisplayId, PhysicalDisplayId displayId,
+                                         std::optional<ui::Size> physicalSize) {
     mPhysicalDisplayIdMap[hwcDisplayId] = displayId;
 
     if (!mPrimaryHwcDisplayId) {
@@ -235,6 +236,7 @@
             std::make_unique<HWC2::impl::Display>(*mComposer.get(), mCapabilities, hwcDisplayId,
                                                   hal::DisplayType::PHYSICAL);
     newDisplay->setConnected(true);
+    newDisplay->setPhysicalSizeInMm(physicalSize);
     displayData.hwcDisplay = std::move(newDisplay);
 }
 
@@ -276,6 +278,47 @@
     return getModesFromLegacyDisplayConfigs(hwcDisplayId);
 }
 
+DisplayConfiguration::Dpi HWComposer::getEstimatedDotsPerInchFromSize(
+        uint64_t hwcDisplayId, const HWCDisplayMode& hwcMode) const {
+    if (!FlagManager::getInstance().correct_dpi_with_display_size()) {
+        return {-1, -1};
+    }
+    if (const auto displayId = toPhysicalDisplayId(hwcDisplayId)) {
+        if (const auto it = mDisplayData.find(displayId.value());
+            it != mDisplayData.end() && it->second.hwcDisplay->getPhysicalSizeInMm()) {
+            ui::Size size = it->second.hwcDisplay->getPhysicalSizeInMm().value();
+            if (hwcMode.width > 0 && hwcMode.height > 0 && size.width > 0 && size.height > 0) {
+                static constexpr float kMmPerInch = 25.4f;
+                return {hwcMode.width * kMmPerInch / size.width,
+                        hwcMode.height * kMmPerInch / size.height};
+            }
+        }
+    }
+    return {-1, -1};
+}
+
+DisplayConfiguration::Dpi HWComposer::correctedDpiIfneeded(
+        DisplayConfiguration::Dpi dpi, DisplayConfiguration::Dpi estimatedDpi) const {
+    // hwc can be unreliable when it comes to dpi. A rough estimated dpi may yield better
+    // results. For instance, libdrm and bad edid may result in a dpi of {350, 290} for a
+    // 16:9 3840x2160 display, which would match a 4:3 aspect ratio.
+    // The logic here checks if hwc was able to provide some dpi, and if so if the dpi
+    // disparity between the axes is more reasonable than a rough estimate, otherwise use
+    // the estimated dpi as a corrected value.
+    if (estimatedDpi.x == -1 || estimatedDpi.x == -1) {
+        return dpi;
+    }
+    if (dpi.x == -1 || dpi.y == -1) {
+        return estimatedDpi;
+    }
+    if (std::min(dpi.x, dpi.y) != 0 && std::min(estimatedDpi.x, estimatedDpi.y) != 0 &&
+        abs(dpi.x - dpi.y) / std::min(dpi.x, dpi.y) >
+                abs(estimatedDpi.x - estimatedDpi.y) / std::min(estimatedDpi.x, estimatedDpi.y)) {
+        return estimatedDpi;
+    }
+    return dpi;
+}
+
 std::vector<HWComposer::HWCDisplayMode> HWComposer::getModesFromDisplayConfigurations(
         uint64_t hwcDisplayId, int32_t maxFrameIntervalNs) const {
     std::vector<hal::DisplayConfiguration> configs;
@@ -294,9 +337,16 @@
                                       .configGroup = config.configGroup,
                                       .vrrConfig = config.vrrConfig};
 
+        const DisplayConfiguration::Dpi estimatedDPI =
+                getEstimatedDotsPerInchFromSize(hwcDisplayId, hwcMode);
         if (config.dpi) {
-            hwcMode.dpiX = config.dpi->x;
-            hwcMode.dpiY = config.dpi->y;
+            const DisplayConfiguration::Dpi dpi =
+                    correctedDpiIfneeded(config.dpi.value(), estimatedDPI);
+            hwcMode.dpiX = dpi.x;
+            hwcMode.dpiY = dpi.y;
+        } else if (estimatedDPI.x != -1 && estimatedDPI.y != -1) {
+            hwcMode.dpiX = estimatedDPI.x;
+            hwcMode.dpiY = estimatedDPI.y;
         }
 
         if (!mEnableVrrTimeout) {
@@ -328,12 +378,14 @@
 
         const int32_t dpiX = getAttribute(hwcDisplayId, configId, hal::Attribute::DPI_X);
         const int32_t dpiY = getAttribute(hwcDisplayId, configId, hal::Attribute::DPI_Y);
-        if (dpiX != -1) {
-            hwcMode.dpiX = static_cast<float>(dpiX) / 1000.f;
-        }
-        if (dpiY != -1) {
-            hwcMode.dpiY = static_cast<float>(dpiY) / 1000.f;
-        }
+        const DisplayConfiguration::Dpi hwcDpi =
+                DisplayConfiguration::Dpi{dpiX == -1 ? dpiY : dpiX / 1000.f,
+                                          dpiY == -1 ? dpiY : dpiY / 1000.f};
+        const DisplayConfiguration::Dpi estimatedDPI =
+                getEstimatedDotsPerInchFromSize(hwcDisplayId, hwcMode);
+        const DisplayConfiguration::Dpi dpi = correctedDpiIfneeded(hwcDpi, estimatedDPI);
+        hwcMode.dpiX = dpi.x;
+        hwcMode.dpiY = dpi.y;
 
         modes.push_back(hwcMode);
     }
@@ -1072,6 +1124,8 @@
             getDisplayIdentificationData(hwcDisplayId, &port, &data);
             if (auto newInfo = parseDisplayIdentificationData(port, data)) {
                 info->deviceProductInfo = std::move(newInfo->deviceProductInfo);
+                info->preferredDetailedTimingDescriptor =
+                        std::move(newInfo->preferredDetailedTimingDescriptor);
             } else {
                 ALOGE("Failed to parse identification data for display %" PRIu64, hwcDisplayId);
             }
@@ -1114,7 +1168,11 @@
     }
 
     if (!isConnected(info->id)) {
-        allocatePhysicalDisplay(hwcDisplayId, info->id);
+        std::optional<ui::Size> size = std::nullopt;
+        if (info->preferredDetailedTimingDescriptor) {
+            size = info->preferredDetailedTimingDescriptor->physicalSizeInMm;
+        }
+        allocatePhysicalDisplay(hwcDisplayId, info->id, size);
     }
     return info;
 }
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index dec4bfe..b95c619 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -134,7 +134,8 @@
     // supported by the HWC can be queried in advance, but allocation may fail for other reasons.
     virtual bool allocateVirtualDisplay(HalVirtualDisplayId, ui::Size, ui::PixelFormat*) = 0;
 
-    virtual void allocatePhysicalDisplay(hal::HWDisplayId, PhysicalDisplayId) = 0;
+    virtual void allocatePhysicalDisplay(hal::HWDisplayId, PhysicalDisplayId,
+                                         std::optional<ui::Size> physicalSize) = 0;
 
     // Attempts to create a new layer on this display
     virtual std::shared_ptr<HWC2::Layer> createLayer(HalDisplayId) = 0;
@@ -349,7 +350,8 @@
     bool allocateVirtualDisplay(HalVirtualDisplayId, ui::Size, ui::PixelFormat*) override;
 
     // Called from SurfaceFlinger, when the state for a new physical display needs to be recreated.
-    void allocatePhysicalDisplay(hal::HWDisplayId, PhysicalDisplayId) override;
+    void allocatePhysicalDisplay(hal::HWDisplayId, PhysicalDisplayId,
+                                 std::optional<ui::Size> physicalSize) override;
 
     // Attempts to create a new layer on this display
     std::shared_ptr<HWC2::Layer> createLayer(HalDisplayId) override;
@@ -532,6 +534,13 @@
     std::optional<DisplayIdentificationInfo> onHotplugDisconnect(hal::HWDisplayId);
     bool shouldIgnoreHotplugConnect(hal::HWDisplayId, bool hasDisplayIdentificationData) const;
 
+    aidl::android::hardware::graphics::composer3::DisplayConfiguration::Dpi
+    getEstimatedDotsPerInchFromSize(uint64_t hwcDisplayId, const HWCDisplayMode& hwcMode) const;
+
+    aidl::android::hardware::graphics::composer3::DisplayConfiguration::Dpi correctedDpiIfneeded(
+            aidl::android::hardware::graphics::composer3::DisplayConfiguration::Dpi dpi,
+            aidl::android::hardware::graphics::composer3::DisplayConfiguration::Dpi estimatedDpi)
+            const;
     std::vector<HWCDisplayMode> getModesFromDisplayConfigurations(uint64_t hwcDisplayId,
                                                                   int32_t maxFrameIntervalNs) const;
     std::vector<HWCDisplayMode> getModesFromLegacyDisplayConfigs(uint64_t hwcDisplayId) const;