[Mellanox] Fix timing issue in lpmode change

platform/mellanox/mlnx-platform-api/sonic_platform/sfp.py

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2019-2023 NVIDIA CORPORATION & AFFILIATES.
+# Copyright (c) 2019-2024 NVIDIA CORPORATION & AFFILIATES.
 # Apache-2.0
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -26,6 +26,7 @@
     import ctypes
     import subprocess
     import os
+    import time
     import threading
     from sonic_py_common.logger import Logger
     from sonic_py_common.general import check_output_pipe
@@ -640,7 +641,8 @@ def set_lpmode(self, lpmode):
                 if api.get_lpmode() == lpmode:
                     return True
                 api.set_lpmode(lpmode)
-                return api.get_lpmode() == lpmode
+                check_lpmode = lambda api, lpmode: api.get_lpmode() == lpmode
+                return utils.wait_until(check_lpmode, 2, 1, api=api, lpmode=lpmode)
             elif DeviceDataManager.is_independent_mode():
                 # FW control under CMIS host management mode. 
                 # Currently, we don't support set LPM under this mode.