Report hotplug error to framework

When active mode can't be found for a display.
Bug: 320703046
Test: atest libsurfaceflinger_unittest:HotplugTest

Change-Id: I352a4b58e97620ee2ce8681fe4e7a1f3307bc0a4

Author: Huihong Luo

services/surfaceflinger/SurfaceFlinger.cpp

@@ -3395,8 +3395,12 @@ const char* SurfaceFlinger::processHotplug(PhysicalDisplayId displayId,
 
     auto [displayModes, activeMode] = loadDisplayModes(displayId);
     if (!activeMode) {
-        // TODO(b/241286153): Report hotplug failure to the framework.
         ALOGE("Failed to hotplug display %s", to_string(displayId).c_str());
+        if (FlagManager::getInstance().hotplug2()) {
+            mScheduler->onHotplugConnectionError(mAppConnectionHandle,
+                                                 static_cast<int32_t>(
+                                                         DisplayHotplugEvent::ERROR_UNKNOWN));
+        }
         getHwComposer().disconnectDisplay(displayId);
         return nullptr;
     }

services/surfaceflinger/tests/unittests/SurfaceFlinger_HotplugTest.cpp

@@ -17,8 +17,14 @@
 #undef LOG_TAG
 #define LOG_TAG "LibSurfaceFlingerUnittests"
 
+#include <aidl/android/hardware/graphics/common/DisplayHotplugEvent.h>
+#include <com_android_graphics_surfaceflinger_flags.h>
+#include <common/test/FlagUtils.h>
 #include "DisplayTransactionTestHelpers.h"
 
+using namespace com::android::graphics::surfaceflinger;
+using ::aidl::android::hardware::graphics::common::DisplayHotplugEvent;
+
 namespace android {
 
 class HotplugTest : public DisplayTransactionTest {};
@@ -87,13 +93,19 @@ TEST_F(HotplugTest, ignoresDuplicateDisconnection) {
 }
 
 TEST_F(HotplugTest, rejectsHotplugIfFailedToLoadDisplayModes) {
+    SET_FLAG_FOR_TEST(flags::connected_display, true);
+
     // Inject a primary display.
     PrimaryDisplayVariant::injectHwcDisplay(this);
 
     using ExternalDisplay = ExternalDisplayVariant;
     constexpr bool kFailedHotplug = true;
     ExternalDisplay::setupHwcHotplugCallExpectations<kFailedHotplug>(this);
 
+    EXPECT_CALL(*mEventThread,
+                onHotplugConnectionError(static_cast<int32_t>(DisplayHotplugEvent::ERROR_UNKNOWN)))
+            .Times(1);
+
     // Simulate a connect event that fails to load display modes due to HWC already having
     // disconnected the display but SF yet having to process the queued disconnect event.
     EXPECT_CALL(*mComposer, getActiveConfig(ExternalDisplay::HWC_DISPLAY_ID, _))