From e2b1bbf0b5b8463d61dfbb205c8f12b4041f23c3 Mon Sep 17 00:00:00 2001
From: Chris Perkins <chris.perkins@intel.com>
Date: Tue, 19 May 2026 12:13:39 -0700
Subject: [PATCH] Revert "[L0] Use immediate command lists for external
 semaphore wait/signal (#21930)"

This reverts commit e928aaedf443761c54d669f09db8fbf1dabc2ec5.
---
 .../source/adapters/level_zero/image.cpp      | 64 +++----------------
 1 file changed, 8 insertions(+), 56 deletions(-)

diff --git a/unified-runtime/source/adapters/level_zero/image.cpp b/unified-runtime/source/adapters/level_zero/image.cpp
index 2095001736319..b21a61e678609 100644
--- a/unified-runtime/source/adapters/level_zero/image.cpp
+++ b/unified-runtime/source/adapters/level_zero/image.cpp
@@ -121,31 +121,15 @@ ur_result_t urBindlessImagesWaitExternalSemaphoreExp(
   // We want to batch these commands to avoid extra submissions (costly)
   bool OkToBatch = true;
 
-  // External semaphore operations require an immediate command list per the
-  // Level Zero spec. If the queue is not using immediate command lists,
-  // we need to get one specifically for this operation.
-  bool NeedTempImmCmdList = !hQueue->UsingImmCmdLists;
-
   ur_ze_event_list_t TmpWaitList;
   UR_CALL(TmpWaitList.createAndRetainUrZeEventList(
       numEventsInWaitList, phEventWaitList, hQueue, UseCopyEngine));
 
   // Get a new command list to be used on this call
   ur_command_list_ptr_t CommandList{};
-  if (NeedTempImmCmdList) {
-    // Ensure the queue group has ImmCmdLists initialized so we can
-    // obtain an immediate command list.
-    auto &QGroup = hQueue->getQueueGroup(UseCopyEngine);
-    if (QGroup.ImmCmdLists.empty()) {
-      QGroup.ImmCmdLists = std::vector<ur_command_list_ptr_t>(
-          QGroup.ZeQueues.size(), hQueue->CommandListMap.end());
-    }
-    CommandList = QGroup.getImmCmdList();
-  } else {
-    UR_CALL(hQueue->Context->getAvailableCommandList(
-        hQueue, CommandList, UseCopyEngine, numEventsInWaitList,
-        phEventWaitList, OkToBatch, nullptr /*ForcedCmdQueue*/));
-  }
+  UR_CALL(hQueue->Context->getAvailableCommandList(
+      hQueue, CommandList, UseCopyEngine, numEventsInWaitList, phEventWaitList,
+      OkToBatch, nullptr /*ForcedCmdQueue*/));
 
   ze_event_handle_t ZeEvent = nullptr;
   ur_event_handle_t InternalEvent;
@@ -173,15 +157,7 @@ ur_result_t urBindlessImagesWaitExternalSemaphoreExp(
              (ZeCommandList, 1, &hExtSemaphore, &WaitParams, ZeEvent,
               WaitList.Length, WaitList.ZeEventList));
 
-  if (NeedTempImmCmdList) {
-    // Immediate command lists auto-execute; no explicit submission needed.
-    // Update LastCommandEvent for in-order queue semantics.
-    if (!CommandList->second.EventList.empty()) {
-      hQueue->LastCommandEvent = CommandList->second.EventList.back();
-    }
-  } else {
-    UR_CALL(hQueue->executeCommandList(CommandList, false, OkToBatch));
-  }
+  UR_CALL(hQueue->executeCommandList(CommandList, false, OkToBatch));
 
   return UR_RESULT_SUCCESS;
 }
@@ -203,31 +179,15 @@ ur_result_t urBindlessImagesSignalExternalSemaphoreExp(
   // We want to batch these commands to avoid extra submissions (costly)
   bool OkToBatch = true;
 
-  // External semaphore operations require an immediate command list per the
-  // Level Zero spec. If the queue is not using immediate command lists,
-  // we need to get one specifically for this operation.
-  bool NeedTempImmCmdList = !hQueue->UsingImmCmdLists;
-
   ur_ze_event_list_t TmpWaitList;
   UR_CALL(TmpWaitList.createAndRetainUrZeEventList(
       numEventsInWaitList, phEventWaitList, hQueue, UseCopyEngine));
 
   // Get a new command list to be used on this call
   ur_command_list_ptr_t CommandList{};
-  if (NeedTempImmCmdList) {
-    // Ensure the queue group has ImmCmdLists initialized so we can
-    // obtain an immediate command list.
-    auto &QGroup = hQueue->getQueueGroup(UseCopyEngine);
-    if (QGroup.ImmCmdLists.empty()) {
-      QGroup.ImmCmdLists = std::vector<ur_command_list_ptr_t>(
-          QGroup.ZeQueues.size(), hQueue->CommandListMap.end());
-    }
-    CommandList = QGroup.getImmCmdList();
-  } else {
-    UR_CALL(hQueue->Context->getAvailableCommandList(
-        hQueue, CommandList, UseCopyEngine, numEventsInWaitList,
-        phEventWaitList, OkToBatch, nullptr /*ForcedCmdQueue*/));
-  }
+  UR_CALL(hQueue->Context->getAvailableCommandList(
+      hQueue, CommandList, UseCopyEngine, numEventsInWaitList, phEventWaitList,
+      OkToBatch, nullptr /*ForcedCmdQueue*/));
 
   ze_event_handle_t ZeEvent = nullptr;
   ur_event_handle_t InternalEvent;
@@ -256,15 +216,7 @@ ur_result_t urBindlessImagesSignalExternalSemaphoreExp(
              (ZeCommandList, 1, &hExtSemaphore, &SignalParams, ZeEvent,
               WaitList.Length, WaitList.ZeEventList));
 
-  if (NeedTempImmCmdList) {
-    // Immediate command lists auto-execute; no explicit submission needed.
-    // Update LastCommandEvent for in-order queue semantics.
-    if (!CommandList->second.EventList.empty()) {
-      hQueue->LastCommandEvent = CommandList->second.EventList.back();
-    }
-  } else {
-    UR_CALL(hQueue->executeCommandList(CommandList, false, OkToBatch));
-  }
+  UR_CALL(hQueue->executeCommandList(CommandList, false, OkToBatch));
 
   return UR_RESULT_SUCCESS;
 }