work around a ue 5.5 regression (UE-212224) while sensecom is running and gloves are connected

Handbook/src/appendix/changelog.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+This patch release addresses a severe regression affecting UE `5.5` projects with specific settings.
+
+### Fixed
+
+- Resolved a critical deadlock between the rendering and game threads in Unreal Engine `5.5` that when `IHeadMountedDisplay::GetHMDMonitorInfo()` is invoked from `FSGXRTracker::GetControllerTransform()` in certain conditions; specifically while SenseCom is running and gloves are present and connected. This issue is [related to critical deadlock issue (UE-212224), occurring during PipelinedFrameState acquisition, which had already been addressed for the plugin versions running on UE `5.6+`](#260---2025-06-04). Because it only gets triggered under specific project settings, we were previously unaware that it also affected IHeadMountedDisplay::GetHMDMonitorInfo() in UE 5.5.
+
 ## [2.7.0] - 2025-11-18
 
 This minor release focuses on delivering performance improvements, made possible by major optimizations in the underlying proprietary SenseGlove libraries, while also introducing some breaking changes.

Source/SenseGloveTracking/Private/SGTracking/SGHMDTracker.cpp

@@ -72,12 +72,12 @@ struct FSGHMDTracker::FStaticImpl
 void FSGHMDTracker::FStaticImpl::GetHMDMonitorInfo(
     IHeadMountedDisplay* Device, IHeadMountedDisplay::MonitorInfo& OutMonitorInfo)
 {
-#if ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION <= 5
+#if ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION <= 4
     Device->GetHMDMonitorInfo(OutMonitorInfo);
     return;
-#endif  /* ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION <= 5 */
+#endif  /* ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION <= 4 */
 
-#if ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION >= 6
+#if ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION >= 5
     TPromise<TOptional<IHeadMountedDisplay::MonitorInfo>> Promise;
     const TFuture<TOptional<IHeadMountedDisplay::MonitorInfo>> Future{Promise.GetFuture()};
 
@@ -100,7 +100,7 @@ void FSGHMDTracker::FStaticImpl::GetHMDMonitorInfo(
             OutMonitorInfo = Result.GetValue();
         }
     }
-#endif  /* ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION >= 6 */
+#endif  /* ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION >= 5 */
 }
 
 FName FSGHMDTracker::GetDeviceName()