[chassis]

don't initialize sfp_event until it is called
deinitialize sfp_event when chassis destructed so that sdk resources can be correctly released.

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

@@ -74,9 +74,14 @@ def __init__(self):
         # move the initialization of each components to their dedicated initializer
         # which will be called from platform
         self.sfp_module_initialized = False
+        self.sfp_event_initialized = False
         self.reboot_cause_initialized = False
         logger.log_info("Chassis loaded successfully")
 
+    def __del__(self):
+        if self.sfp_event_initialized:
+            self.sfp_event.deinitialize()
+
     def initialize_psu(self):
         from sonic_platform.psu import Psu
         # Initialize PSU list
@@ -104,7 +109,7 @@ def initialize_fan(self):
 
     def initialize_sfp(self):
         from sonic_platform.sfp import SFP
-        from sonic_platform.sfp_event import sfp_event
+
         self.sfp_module = SFP
 
         # Initialize SFP list
@@ -121,11 +126,6 @@ def initialize_sfp(self):
                 sfp_module = SFP(index, 'SFP')
             self._sfp_list.append(sfp_module)
 
-        # Initialize SFP event
-        self.sfp_event = sfp_event()
-        self.sfp_event.initialize()
-        self.MAX_SELECT_EVENT_RETURNED = self.PORT_END
-
         self.sfp_module_initialized = True
 
     def initialize_thermals(self):
@@ -488,6 +488,14 @@ def get_change_event(self, timeout=0):
                       indicates that fan 0 has been removed, fan 2
                       has been inserted and sfp 11 has been removed.
         """
+        # Initialize SFP event first
+        if not self.sfp_event_initialized:
+            from sonic_platform.sfp_event import sfp_event
+            self.sfp_event = sfp_event()
+            self.sfp_event.initialize()
+            self.MAX_SELECT_EVENT_RETURNED = self.PORT_END
+            self.sfp_event_initialized = True
+
         wait_for_ever = (timeout == 0)
         port_dict = {}
         if wait_for_ever: