SF: Remove obsolete HWComposer members

Remove mExternalHwcDisplayId, an obsolete special case for legacy multi-
display mode. Assert primary display existence instead of propagating to
callers, which is closer to how headless mode would work, i.e. injecting
a placeholder primary display. Remove isVirtual checks now that they are
enforced at compile time. Prevent primary display disconnection for now.

Bug: 182939859
Test: libsurfaceflinger_unittest
Change-Id: I507db6a3ac0bda93005a86b38cca6ebbcd5c0155
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index a790b4c..b0443f7 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -212,8 +212,6 @@
     RETURN_IF_INVALID_DISPLAY(*displayId, false);
 
     auto& displayData = mDisplayData[*displayId];
-    LOG_FATAL_IF(displayData.isVirtual, "%s: Invalid operation on virtual display with ID %s",
-                 __FUNCTION__, to_string(*displayId).c_str());
 
     {
         // There have been reports of HWCs that signal several vsync events
@@ -271,7 +269,6 @@
     display->setConnected(true);
     auto& displayData = mDisplayData[displayId];
     displayData.hwcDisplay = std::move(display);
-    displayData.isVirtual = true;
     return true;
 }
 
@@ -279,10 +276,8 @@
                                          PhysicalDisplayId displayId) {
     mPhysicalDisplayIdMap[hwcDisplayId] = displayId;
 
-    if (!mInternalHwcDisplayId) {
-        mInternalHwcDisplayId = hwcDisplayId;
-    } else if (mInternalHwcDisplayId != hwcDisplayId && !mExternalHwcDisplayId) {
-        mExternalHwcDisplayId = hwcDisplayId;
+    if (!mPrimaryHwcDisplayId) {
+        mPrimaryHwcDisplayId = hwcDisplayId;
     }
 
     auto& displayData = mDisplayData[displayId];
@@ -372,7 +367,7 @@
     ui::DisplayConnectionType type;
     const auto error = hwcDisplay->getConnectionType(&type);
 
-    const auto FALLBACK_TYPE = hwcDisplay->getId() == mInternalHwcDisplayId
+    const auto FALLBACK_TYPE = hwcDisplay->getId() == mPrimaryHwcDisplayId
             ? ui::DisplayConnectionType::Internal
             : ui::DisplayConnectionType::External;
 
@@ -428,9 +423,6 @@
     RETURN_IF_INVALID_DISPLAY(displayId);
     auto& displayData = mDisplayData[displayId];
 
-    LOG_FATAL_IF(displayData.isVirtual, "%s: Invalid operation on virtual display with ID %s",
-                 __FUNCTION__, to_string(displayId).c_str());
-
     // NOTE: we use our own internal lock here because we have to call
     // into the HWC with the lock held, and we want to make sure
     // that even if HWC blocks (which it shouldn't), it won't
@@ -597,14 +589,11 @@
 status_t HWComposer::setPowerMode(PhysicalDisplayId displayId, hal::PowerMode mode) {
     RETURN_IF_INVALID_DISPLAY(displayId, BAD_INDEX);
 
-    const auto& displayData = mDisplayData[displayId];
-    LOG_FATAL_IF(displayData.isVirtual, "%s: Invalid operation on virtual display with ID %s",
-                 __FUNCTION__, to_string(displayId).c_str());
-
     if (mode == hal::PowerMode::OFF) {
         setVsyncEnabled(displayId, hal::Vsync::DISABLE);
     }
 
+    const auto& displayData = mDisplayData[displayId];
     auto& hwcDisplay = displayData.hwcDisplay;
     switch (mode) {
         case hal::PowerMode::OFF:
@@ -677,13 +666,8 @@
     RETURN_IF_INVALID_DISPLAY(displayId);
     auto& displayData = mDisplayData[displayId];
     const auto hwcDisplayId = displayData.hwcDisplay->getId();
+    LOG_ALWAYS_FATAL_IF(hwcDisplayId == mPrimaryHwcDisplayId);
 
-    // TODO(b/74619554): Select internal/external display from remaining displays.
-    if (hwcDisplayId == mInternalHwcDisplayId) {
-        mInternalHwcDisplayId.reset();
-    } else if (hwcDisplayId == mExternalHwcDisplayId) {
-        mExternalHwcDisplayId.reset();
-    }
     mPhysicalDisplayIdMap.erase(hwcDisplayId);
     mDisplayData.erase(displayId);
 }
@@ -693,9 +677,6 @@
     RETURN_IF_INVALID_DISPLAY(displayId, BAD_INDEX);
     const auto& displayData = mDisplayData[displayId];
 
-    LOG_FATAL_IF(!displayData.isVirtual, "%s: Invalid operation on physical display with ID %s",
-                 __FUNCTION__, to_string(displayId).c_str());
-
     auto error = displayData.hwcDisplay->setOutputBuffer(buffer, acquireFence);
     RETURN_IF_HWC_ERROR(error, displayId, UNKNOWN_ERROR);
     return NO_ERROR;
@@ -853,8 +834,7 @@
 
 std::optional<hal::HWDisplayId> HWComposer::fromPhysicalDisplayId(
         PhysicalDisplayId displayId) const {
-    if (const auto it = mDisplayData.find(displayId);
-        it != mDisplayData.end() && !it->second.isVirtual) {
+    if (const auto it = mDisplayData.find(displayId); it != mDisplayData.end()) {
         return it->second.hwcDisplay->getId();
     }
     return {};
@@ -868,7 +848,8 @@
         return true;
     }
 
-    if (!mHasMultiDisplaySupport && mInternalHwcDisplayId && mExternalHwcDisplayId) {
+    // Legacy mode only supports IDs LEGACY_DISPLAY_TYPE_PRIMARY and LEGACY_DISPLAY_TYPE_EXTERNAL.
+    if (!mHasMultiDisplaySupport && mPhysicalDisplayIdMap.size() == 2) {
         ALOGE("Ignoring connection of tertiary display %" PRIu64, hwcDisplayId);
         return true;
     }
@@ -909,7 +890,7 @@
         }
 
         info = [this, hwcDisplayId, &port, &data, hasDisplayIdentificationData] {
-            const bool isPrimary = !mInternalHwcDisplayId;
+            const bool isPrimary = !mPrimaryHwcDisplayId;
             if (mHasMultiDisplaySupport) {
                 if (const auto info = parseDisplayIdentificationData(port, data)) {
                     return *info;
@@ -922,8 +903,8 @@
             }
 
             return DisplayIdentificationInfo{.id = PhysicalDisplayId::fromPort(port),
-                                             .name = isPrimary ? "Internal display"
-                                                               : "External display",
+                                             .name = isPrimary ? "Primary display"
+                                                               : "Secondary display",
                                              .deviceProductInfo = std::nullopt};
         }();
     }
@@ -936,9 +917,12 @@
 
 std::optional<DisplayIdentificationInfo> HWComposer::onHotplugDisconnect(
         hal::HWDisplayId hwcDisplayId) {
+    LOG_ALWAYS_FATAL_IF(hwcDisplayId == mPrimaryHwcDisplayId,
+                        "Primary display cannot be disconnected.");
+
     const auto displayId = toPhysicalDisplayId(hwcDisplayId);
     if (!displayId) {
-        ALOGE("Ignoring disconnection of invalid HWC display %" PRIu64, hwcDisplayId);
+        LOG_HWC_DISPLAY_ERROR(hwcDisplayId, "Invalid HWC display");
         return {};
     }
 
@@ -947,7 +931,7 @@
     if (isConnected(*displayId)) {
         mDisplayData[*displayId].hwcDisplay->setConnected(false);
     } else {
-        ALOGW("Attempted to disconnect unknown display %" PRIu64, hwcDisplayId);
+        LOG_HWC_DISPLAY_ERROR(hwcDisplayId, "Already disconnected");
     }
     // The cleanup of Disconnect is handled through HWComposer::disconnectDisplay
     // via SurfaceFlinger's onHotplugReceived callback handling
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index 49f96d9..0a090da 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef ANDROID_SF_HWCOMPOSER_H
-#define ANDROID_SF_HWCOMPOSER_H
+#pragma once
 
 #include <cstdint>
 #include <future>
@@ -228,14 +227,18 @@
     virtual const std::unordered_map<std::string, bool>& getSupportedLayerGenericMetadata()
             const = 0;
 
-    // for debugging ----------------------------------------------------------
     virtual void dump(std::string& out) const = 0;
 
     virtual Hwc2::Composer* getComposer() const = 0;
 
-    // TODO(b/74619554): Remove special cases for internal/external display.
-    virtual std::optional<hal::HWDisplayId> getInternalHwcDisplayId() const = 0;
-    virtual std::optional<hal::HWDisplayId> getExternalHwcDisplayId() const = 0;
+    // Returns the first display connected at boot. It cannot be disconnected, which implies an
+    // internal connection type. Its connection via HWComposer::onHotplug, which in practice is
+    // immediately after HWComposer construction, must occur before any call to this function.
+    //
+    // TODO(b/182939859): Remove special cases for primary display.
+    virtual hal::HWDisplayId getPrimaryHwcDisplayId() const = 0;
+    virtual PhysicalDisplayId getPrimaryDisplayId() const = 0;
+    virtual bool isHeadless() const = 0;
 
     virtual std::optional<PhysicalDisplayId> toPhysicalDisplayId(hal::HWDisplayId) const = 0;
     virtual std::optional<hal::HWDisplayId> fromPhysicalDisplayId(PhysicalDisplayId) const = 0;
@@ -366,14 +369,19 @@
 
     Hwc2::Composer* getComposer() const override { return mComposer.get(); }
 
-    // TODO(b/74619554): Remove special cases for internal/external display.
-    std::optional<hal::HWDisplayId> getInternalHwcDisplayId() const override {
-        return mInternalHwcDisplayId;
+    hal::HWDisplayId getPrimaryHwcDisplayId() const override {
+        LOG_ALWAYS_FATAL_IF(!mPrimaryHwcDisplayId, "Missing HWC primary display");
+        return *mPrimaryHwcDisplayId;
     }
-    std::optional<hal::HWDisplayId> getExternalHwcDisplayId() const override {
-        return mExternalHwcDisplayId;
+
+    PhysicalDisplayId getPrimaryDisplayId() const override {
+        const auto id = toPhysicalDisplayId(getPrimaryHwcDisplayId());
+        LOG_ALWAYS_FATAL_IF(!id, "Missing primary display");
+        return *id;
     }
 
+    virtual bool isHeadless() const override { return !mPrimaryHwcDisplayId; }
+
     std::optional<PhysicalDisplayId> toPhysicalDisplayId(hal::HWDisplayId) const override;
     std::optional<hal::HWDisplayId> fromPhysicalDisplayId(PhysicalDisplayId) const override;
 
@@ -382,12 +390,9 @@
     friend TestableSurfaceFlinger;
 
     struct DisplayData {
-        bool isVirtual = false;
         std::unique_ptr<HWC2::Display> hwcDisplay;
         sp<Fence> lastPresentFence = Fence::NO_FENCE; // signals when the last set op retires
         std::unordered_map<HWC2::Layer*, sp<Fence>> releaseFences;
-        buffer_handle_t outbufHandle = nullptr;
-        sp<Fence> outbufAcquireFence = Fence::NO_FENCE;
 
         bool validateWasSkipped;
         hal::Error presentError;
@@ -418,8 +423,7 @@
     bool mRegisteredCallback = false;
 
     std::unordered_map<hal::HWDisplayId, PhysicalDisplayId> mPhysicalDisplayIdMap;
-    std::optional<hal::HWDisplayId> mInternalHwcDisplayId;
-    std::optional<hal::HWDisplayId> mExternalHwcDisplayId;
+    std::optional<hal::HWDisplayId> mPrimaryHwcDisplayId;
     bool mHasMultiDisplaySupport = false;
 
     const size_t mMaxVirtualDisplayDimension;
@@ -428,5 +432,3 @@
 
 } // namespace impl
 } // namespace android
-
-#endif // ANDROID_SF_HWCOMPOSER_H