diff --git a/GPCS4/Graphics/Gcn/GcnCompiler.cpp b/GPCS4/Graphics/Gcn/GcnCompiler.cpp
index 121e7af8..bdba9f9f 100644
--- a/GPCS4/Graphics/Gcn/GcnCompiler.cpp
+++ b/GPCS4/Graphics/Gcn/GcnCompiler.cpp
@@ -1856,19 +1856,19 @@ namespace sce::gcn
 	{
 		switch (sv)
 		{
-			case GcnSystemValue::SubgroupID:
+			case GcnSystemValue::SubgroupInvocationID:
 			{
-				if (m_common.subgroupId == 0)
+				if (m_common.subgroupInvocationId == 0)
 				{
-					m_common.subgroupId = emitNewBuiltinVariable({ { GcnScalarType::Uint32, 1, 0 },
-																   spv::StorageClassInput },
-																 spv::BuiltInSubgroupId,
-																 "subgroup_id");
+					m_common.subgroupInvocationId = emitNewBuiltinVariable({ { GcnScalarType::Uint32, 1, 0 },
+																			 spv::StorageClassInput },
+																		   spv::BuiltInSubgroupLocalInvocationId,
+																		   "invocation_id");
 				}
 
 				GcnRegisterPointer ptr;
 				ptr.type = { GcnScalarType::Uint32, 1 };
-				ptr.id   = m_common.subgroupId;
+				ptr.id   = m_common.subgroupInvocationId;
 				return emitValueLoad(ptr);
 			}
 				break;
@@ -1896,7 +1896,6 @@ namespace sce::gcn
 			case GcnSystemValue::SubgroupLeMask:
 			case GcnSystemValue::SubgroupLtMask:
 			case GcnSystemValue::SubgroupSize:
-			case GcnSystemValue::SubgroupInvocationID:
 			default:
 				Logger::exception(util::str::formatex(
 					"GcnCompiler: Unhandled Common SV input: ", (uint32_t)sv));
@@ -2204,6 +2203,22 @@ namespace sce::gcn
 				return emitValueLoad(ptr);
 			}
 				break;
+			case GcnSystemValue::SubgroupID:
+			{
+				if (m_common.subgroupId == 0)
+				{
+					m_common.subgroupId = emitNewBuiltinVariable({ { GcnScalarType::Uint32, 1, 0 },
+																   spv::StorageClassInput },
+																 spv::BuiltInSubgroupId,
+																 "subgroup_id");
+				}
+
+				GcnRegisterPointer ptr;
+				ptr.type = { GcnScalarType::Uint32, 1 };
+				ptr.id   = m_common.subgroupId;
+				return emitValueLoad(ptr);
+			}
+				break;
 			default:
 				Logger::exception(util::str::formatex(
 					"GcnCompiler: Unhandled CS SV input: ", (uint32_t)sv));
diff --git a/GPCS4/Graphics/Gcn/GcnCompiler.h b/GPCS4/Graphics/Gcn/GcnCompiler.h
index 5e1e0fe1..35db82e2 100644
--- a/GPCS4/Graphics/Gcn/GcnCompiler.h
+++ b/GPCS4/Graphics/Gcn/GcnCompiler.h
@@ -577,6 +577,8 @@ namespace sce::gcn
 			// Copy vk_layer_settings.txt from Misc folder to your
 			// Current Working Directory or use vkconfig.exe from SDK
 			// to enable shader debug printf.
+			// Note that normally we need to specify big enough
+			// buffer size and limit the number of messages by conditionally using invocation ID
 			//
 			// Format for specifier is "%"precision <d, i, o, u, x, X, a, A, e, E, f, F, g, G, or ul>
 			// Format for vector specifier is "%"precision"v" [2, 3, or 4] [specifiers list above]
@@ -584,32 +586,19 @@ namespace sce::gcn
 			// To conditionally print something,
 			// copy and edit the following code:
 			// 
-			// if (m_header->key().name() == "SHDR_AF20AC1F702451D8" && m_programCounter == 0x70)
-			// {
-			// 	 uint32_t labelBegin = m_module.allocateId();
-			// 	 uint32_t labelEnd   = m_module.allocateId();
-			// 	 m_module.opSelectionMerge(labelEnd, spv::SelectionControlMaskNone);
-			// 	 m_module.opBranchConditional(condition, labelBegin, labelEnd);
-			// 	 m_module.opLabel(labelBegin);
-			// 	 emitDebugPrintf("condition %d\n", condition);
-			// 	 m_module.opBranch(labelEnd);
-			// 	 m_module.opLabel(labelEnd);
-			// }
-
-			// TODO:
-			// There may be some bugs for current implementation
-			// (or bugs for validation layer, I'm not sure),
-			// It can not print more than one debug string,
-			// and even worse, the validation layer always complains 
-			// buffer size not enough even I provide 65536 bytes.
-			// And crashes randomly.
-			// I've compared the spir-v code generated by
-			// this function and glslc compiler, and I see
-			// no difference, so I don't know why by now.
-			// 
-			// This doesn't mean the function is useless,
-			// it's still very powerful, although the experience
-			// is poor.
+			//if (m_header->key().name() == "SHDR_AF20AC1F702451D8" && m_programCounter == 0x70)
+			//{
+			//	auto     invId      = emitCommonSystemValueLoad(GcnSystemValue::SubgroupInvocationID, 0);
+			//	auto     condition  = m_module.opIEqual(m_module.defBoolType(), invId.id, m_module.constu32(1));
+			//	uint32_t labelBegin = m_module.allocateId();
+			//	uint32_t labelEnd   = m_module.allocateId();
+			//	m_module.opSelectionMerge(labelEnd, spv::SelectionControlMaskNone);
+			//	m_module.opBranchConditional(condition, labelBegin, labelEnd);
+			//	m_module.opLabel(labelBegin);
+			//	emitDebugPrintf("id %X\n", invId.id);
+			//	m_module.opBranch(labelEnd);
+			//	m_module.opLabel(labelEnd);
+			//}
 
 #ifdef GCN_SHADER_DEBUG_PRINTF
 			const int count = sizeof...(args);
diff --git a/Misc/vk_layer_settings.txt b/Misc/vk_layer_settings.txt
index ba358ca7..41bb0f6c 100644
--- a/Misc/vk_layer_settings.txt
+++ b/Misc/vk_layer_settings.txt
@@ -5,7 +5,7 @@
 # =====================
 # <LayerIdentifier>.debug_action
 # Specifies what action is to be taken when a layer reports information
-khronos_validation.debug_action = 
+khronos_validation.debug_action = VK_DBG_LAYER_ACTION_LOG_MSG
 
 # Log Filename
 # =====================
@@ -67,7 +67,7 @@ khronos_validation.printf_verbose = false
 # =====================
 # <LayerIdentifier>.printf_buffer_size
 # Set the size in bytes of the buffer used by debug printf
-khronos_validation.printf_buffer_size = 1024
+khronos_validation.printf_buffer_size = 65536
 
 # Fine Grained Locking
 # =====================