[UR][L0] Fix duplicate driver reporting given legacy and new drivers

- Fix an issue where two drivers may report driver handles in reverse
  order causing duplicate handles to be reported to the user.
- Updated driver version check to ensure the same driver is only ever
  reported once.

Signed-off-by: Neil R. Spruit <[email protected]>

Author: nrspruit

unified-runtime/source/adapters/level_zero/adapter.cpp

@@ -178,25 +178,38 @@ ur_result_t initPlatforms(ur_adapter_handle_t_ *adapter, PlatformVec &platforms,
     ZeDrivers.assign(ZeInitDriversHandles.begin(), ZeInitDriversHandles.end());
     if (ZeDriverGetCount > 0 && adapter->ZeInitDriversCount > 0) {
       for (uint32_t X = 0; X < adapter->ZeInitDriversCount; ++X) {
+        // zeDriverGet and zeInitDrivers can return the driver handles in
+        // reverse order based on driver ordering causing an issue if the
+        // drivers are expected to be in the same order. To resolve, this loop
+        // checks if the driver from zeDriverGet already exists in zeInitDrivers
+        // and only adds it if it is not found.
+        bool unMatchedDriverHandle = true;
         for (uint32_t Y = 0; Y < ZeDriverGetCount; ++Y) {
           ZeStruct<ze_driver_properties_t> ZeDriverGetProperties;
           ZeStruct<ze_driver_properties_t> ZeInitDriverProperties;
           ZE2UR_CALL(zeDriverGetProperties,
                      (ZeDriverGetHandles[Y], &ZeDriverGetProperties));
           ZE2UR_CALL(zeDriverGetProperties,
                      (ZeInitDriversHandles[X], &ZeInitDriverProperties));
-          // If zeDriverGet driver is different from zeInitDriver driver, add it
-          // to the list. This allows for older drivers to be used alongside
-          // newer drivers.
-          if (ZeDriverGetProperties.driverVersion !=
+          // If zeDriverGet driver is the same version as zeInitDriver driver,
+          // then do not add it again.
+          if (ZeDriverGetProperties.driverVersion ==
               ZeInitDriverProperties.driverVersion) {
             UR_LOG(DEBUG,
-                   "\nzeDriverHandle {} added to the zeInitDrivers list "
-                   "of possible handles.\n",
+                   "\nzeDriverHandle {} matched between zeDriverGet and "
+                   "zeInitDrivers. Not adding duplicate driver to list\n",
                    ZeDriverGetHandles[Y]);
-            ZeDrivers.push_back(ZeDriverGetHandles[Y]);
+            unMatchedDriverHandle = false;
+            break;
           }
         }
+        if (unMatchedDriverHandle) {
+          UR_LOG(DEBUG,
+                 "\nzeDriverHandle {} not found in zeInitDrivers. Adding to "
+                 "driver list.\n",
+                 ZeDriverGetHandles[Y]);
+          ZeDrivers.push_back(ZeDriverGetHandles[Y]);
+        }
       }
     }
   } else {