Enable stateful rt stack for sync raytracing

Enable stateful rt stack for sync raytracing

Author: jaladreips

IGC/AdaptorCommon/RayTracing/RayTracingInterface.cpp

@@ -103,7 +103,7 @@ static void setupRegionBTIs(CodeGenContext* pContext)
             rtInfo.SWStackSurfaceStateOffset = BaseOffset++;
         }
 
-        if (IGC_IS_FLAG_DISABLED(DisableStatefulRTSyncStackAccess4RTShader))
+        if (IGC_IS_FLAG_DISABLED(DisableStatefulRTSyncStackAccess4RTShader) && pContext->m_DriverInfo.allowStatefulStackForSyncRaytracing())
         {
             rtInfo.RTSyncStackAddrspace = getAddrspace();
             rtInfo.RTSyncStackSurfaceStateOffset = BaseOffset++;

IGC/Compiler/CISACodeGen/DriverInfo.hpp

@@ -392,6 +392,8 @@ namespace IGC
         virtual bool supportsVRT() const { return true; }
 
         virtual bool supportsUniformPrivateMemorySpace() const { return false; }
+
+        virtual bool allowStatefulStackForSyncRaytracing() const { return false; }
 protected:
     bool autoGRFSelection = false;
     };

IGC/common/igc_flags.h

@@ -975,7 +975,7 @@ DECLARE_IGC_GROUP("Raytracing Options")
     DECLARE_IGC_REGKEY(bool, DisableStatefulRTSyncStackAccess, true, "do stateless rather than stateful accesses to the HW portion of the sync stack", true)
     DECLARE_IGC_REGKEY(bool, DisableStatefulSWHotZoneAccess, false, "do stateless rather than stateful accesses to the SW HotZone", true)
     DECLARE_IGC_REGKEY(bool, DisableStatefulSWStackAccess, false, "do stateless rather than stateful accesses to the SW Stack", true)
-    DECLARE_IGC_REGKEY(bool, DisableStatefulRTSyncStackAccess4RTShader, true, "do stateless rather than stateful accesses to the HW portion of the sync stack. RT Shader only.", true)
+    DECLARE_IGC_REGKEY(bool, DisableStatefulRTSyncStackAccess4RTShader, false, "do stateless rather than stateful accesses to the HW portion of the sync stack. RT Shader only.", true)
     DECLARE_IGC_REGKEY(bool, DisableStatefulRTSyncStackAccess4nonRTShader, true, "do stateless rather than stateful accesses to the HW portion of the sync stack. nonRT Shader only.", true)
     DECLARE_IGC_REGKEY(bool, DisableRTBindlessAccess, false, "do bindful rather than bindless accesses to raytracing memory", true)
     DECLARE_IGC_REGKEY(bool, DisableRTStackOpts, false, "Disable some optimizations that minimize reads/writes to the RTStack", true)