Restore pre-emphasis when LT is transitioned from ON to OFF

Signed-off-by: Dante Su <[email protected]>

Author: ds952811

orchagent/port.h

@@ -174,6 +174,9 @@ class Port
     sai_object_id_t  m_switch_id = 0;
     sai_object_id_t  m_line_side_id = 0;
 
+    /* pre-emphasis */
+    std::map<sai_port_serdes_attr_t, std::vector<uint32_t>> m_preemphasis;
+
     bool m_fec_cfg = false;
     bool m_an_cfg = false;
     bool m_port_cap_lt = false; /* Port Capability - LinkTraining */

orchagent/portsorch.cpp

@@ -3100,6 +3100,12 @@ void PortsOrch::doPortTask(Consumer &consumer)
                         p.m_link_training = lt;
                         m_portList[alias] = p;
                         updatePortStatePoll(p, PORT_STATE_POLL_LT, (lt > 0));
+
+                        // Restore pre-emphasis when LT is transitioned from ON to OFF
+                        if ((p.m_link_training < 1) && (serdes_attr.size() == 0))
+                        {
+                            serdes_attr = p.m_preemphasis;
+                        }
                     }
                 }
 
@@ -3440,17 +3446,24 @@ void PortsOrch::doPortTask(Consumer &consumer)
 
                 if (serdes_attr.size() != 0)
                 {
-                    if (setPortSerdesAttribute(p.m_port_id, serdes_attr))
+                    if (p.m_link_training > 0)
+                    {
+                        SWSS_LOG_NOTICE("Save port %s preemphasis for LT", alias.c_str());
+                        p.m_preemphasis = serdes_attr;
+                        m_portList[alias] = p;
+                    }
+                    else if (setPortSerdesAttribute(p.m_port_id, serdes_attr))
                     {
-                        SWSS_LOG_NOTICE("Set port %s  preemphasis is success", alias.c_str());
+                        SWSS_LOG_NOTICE("Set port %s preemphasis is success", alias.c_str());
+                        p.m_preemphasis = serdes_attr;
+                        m_portList[alias] = p;
                     }
                     else
                     {
                         SWSS_LOG_ERROR("Failed to set port %s pre-emphasis", alias.c_str());
                         it++;
                         continue;
                     }
-
                 }
 
                 /* Last step set port admin status */