Index: /jack2/trunk/jackmp/common/JackLockedEngine.h
===================================================================
--- /jack2/trunk/jackmp/common/JackLockedEngine.h (revision 3853)
+++ /jack2/trunk/jackmp/common/JackLockedEngine.h (revision 3901)
@@ -38,5 +38,4 @@
     // Assuming thread cancellation, must rethrow
     throw;
-    
 }
 */
@@ -63,9 +62,10 @@
     }                                               \
 
+
 /*!
 \brief Locked Engine, access to methods is serialized using a mutex.
 */
 
-class SERVER_EXPORT JackLockedEngine : public JackLockAble
+class SERVER_EXPORT JackLockedEngine 
 {
     private:
@@ -100,5 +100,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.ClientCheck(name, name_res, protocol, options, status);
             CATCH_EXCEPTION_RETURN
@@ -107,5 +107,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.ClientExternalOpen(name, pid, ref, shared_engine, shared_client, shared_graph_manager);
             CATCH_EXCEPTION_RETURN
@@ -114,5 +114,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.ClientInternalOpen(name, ref, shared_engine, shared_manager, client, wait);
             CATCH_EXCEPTION_RETURN
@@ -122,6 +122,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.ClientExternalClose(refnum);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.ClientExternalClose(refnum) : - 1;
             CATCH_EXCEPTION_RETURN
         }
@@ -129,6 +129,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.ClientInternalClose(refnum, wait);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.ClientInternalClose(refnum, wait) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -137,6 +137,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.ClientActivate(refnum, is_real_time);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.ClientActivate(refnum, is_real_time) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -144,6 +144,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.ClientDeactivate(refnum);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.ClientDeactivate(refnum) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -153,5 +153,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.GetInternalClientName(int_ref, name_res);
             CATCH_EXCEPTION_RETURN
@@ -160,5 +160,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.InternalClientHandle(client_name, status, int_ref);
             CATCH_EXCEPTION_RETURN
@@ -167,5 +167,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
+            // Client is tested in fEngine.InternalClientUnload
             return fEngine.InternalClientUnload(refnum, status);
             CATCH_EXCEPTION_RETURN
@@ -176,6 +177,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.PortRegister(refnum, name, type, flags, buffer_size, port);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.PortRegister(refnum, name, type, flags, buffer_size, port) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -183,6 +184,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.PortUnRegister(refnum, port);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.PortUnRegister(refnum, port) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -191,6 +192,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.PortConnect(refnum, src, dst);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.PortConnect(refnum, src, dst) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -198,6 +199,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.PortDisconnect(refnum, src, dst);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.PortDisconnect(refnum, src, dst) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -206,6 +207,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.PortConnect(refnum, src, dst);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.PortConnect(refnum, src, dst) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -213,6 +214,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.PortDisconnect(refnum, src, dst);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.PortDisconnect(refnum, src, dst) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -221,6 +222,6 @@
         {
             TRY_CALL
-            JackLock lock(this);
-            return fEngine.PortRename(refnum, port, name);
+            JackLock lock(&fEngine);
+            return (fEngine.CheckClient(refnum)) ? fEngine.PortRename(refnum, port, name) : -1;
             CATCH_EXCEPTION_RETURN
         }
@@ -242,13 +243,12 @@
         void NotifyXRun(int refnum)
         {
-            TRY_CALL
-            JackLock lock(this);
+            // RT : no lock
             fEngine.NotifyXRun(refnum);
-            CATCH_EXCEPTION
-        }
+        }
+        
         void NotifyGraphReorder()
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             fEngine.NotifyGraphReorder();
             CATCH_EXCEPTION
@@ -257,5 +257,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             fEngine.NotifyBufferSize(buffer_size);
             CATCH_EXCEPTION
@@ -264,5 +264,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             fEngine.NotifySampleRate(sample_rate);
             CATCH_EXCEPTION
@@ -271,5 +271,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             fEngine.NotifyFreewheel(onoff);
             CATCH_EXCEPTION
@@ -279,5 +279,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             fEngine.NotifyFailure(code, reason);
             CATCH_EXCEPTION
@@ -287,5 +287,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.GetClientPID(name);
             CATCH_EXCEPTION_RETURN
@@ -295,5 +295,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.GetClientRefNum(name);
             CATCH_EXCEPTION_RETURN
@@ -303,5 +303,5 @@
         {
             TRY_CALL
-            JackLock lock(this);
+            JackLock lock(&fEngine);
             return fEngine.NotifyQuit();
             CATCH_EXCEPTION
Index: /jack2/trunk/jackmp/common/JackEngineControl.h
===================================================================
--- /jack2/trunk/jackmp/common/JackEngineControl.h (revision 3782)
+++ /jack2/trunk/jackmp/common/JackEngineControl.h (revision 3901)
@@ -163,5 +163,5 @@
     
     // XRun
-    void NotifyXRun(float delayed_usecs);
+    void NotifyXRun(jack_time_t callback_usecs, float delayed_usecs);
     void ResetXRun()
     {
Index: /jack2/trunk/jackmp/common/JackEngine.cpp
===================================================================
--- /jack2/trunk/jackmp/common/JackEngine.cpp (revision 3853)
+++ /jack2/trunk/jackmp/common/JackEngine.cpp (revision 3901)
@@ -35,6 +35,4 @@
 namespace Jack
 {
-
-#define AssertRefnum(ref) assert(ref >= 0 && ref < CLIENT_NUM);
 
 JackEngine::JackEngine(JackGraphManager* manager,
@@ -214,26 +212,26 @@
 
     // The client may be notified by the RT thread while closing
-    if (!client) {
-        jack_log("JackEngine::NotifyClient: client not available anymore");
-    } else if (client->GetClientControl()->fCallback[event]) {
-        if (client->ClientNotify(refnum, client->GetClientControl()->fName, event, sync, message, value1, value2) < 0)
-            jack_error("NotifyClient fails name = %s event = %ld val1 = %ld val2 = %ld", client->GetClientControl()->fName, event, value1, value2);
-    } else {
-        jack_log("JackEngine::NotifyClient: no callback for event = %ld", event);
-    }
-}
-
-void JackEngine::NotifyClients(int event, int sync, const char*  message, int value1, int value2)
+    if (client) {
+    
+        if (client && client->GetClientControl()->fCallback[event]) {
+            /*
+                Important for internal clients : unlock before calling the notification callbacks.
+            */
+            bool res = fMutex.Unlock();
+            if (client->ClientNotify(refnum, client->GetClientControl()->fName, event, sync, message, value1, value2) < 0)
+                jack_error("NotifyClient fails name = %s event = %ld val1 = %ld val2 = %ld", client->GetClientControl()->fName, event, value1, value2);
+            if (res)
+                fMutex.Lock();
+       
+        } else {
+            jack_log("JackEngine::NotifyClient: no callback for event = %ld", event);
+        }
+    }
+}
+
+void JackEngine::NotifyClients(int event, int sync, const char* message, int value1, int value2)
 {
     for (int i = 0; i < CLIENT_NUM; i++) {
-        JackClientInterface* client = fClientTable[i];
-        if (client) {
-            if (client->GetClientControl()->fCallback[event]) {
-                if (client->ClientNotify(i, client->GetClientControl()->fName, event, sync, message, value1, value2) < 0)
-                    jack_error("NotifyClient fails name = %s event = %ld val1 = %ld val2 = %ld", client->GetClientControl()->fName, event, value1, value2);
-            } else {
-                jack_log("JackEngine::NotifyClients: no callback for event = %ld", event);
-            }
-        }
+        NotifyClient(i, event, sync, message, value1, value2);
     }
 }
@@ -275,6 +273,5 @@
 {
     // Use the audio thread => request thread communication channel
-    fEngineControl->ResetFrameTime(callback_usecs);
-    fEngineControl->NotifyXRun(delayed_usecs);
+    fEngineControl->NotifyXRun(callback_usecs, delayed_usecs);
     fChannel.Notify(ALL_CLIENTS, kXRunCallback, 0);
 }
@@ -349,12 +346,7 @@
 int JackEngine::GetInternalClientName(int refnum, char* name_res)
 {
-    AssertRefnum(refnum);
     JackClientInterface* client = fClientTable[refnum];
-    if (client) {
-        strncpy(name_res, client->GetClientControl()->fName, JACK_CLIENT_NAME_SIZE);
-        return 0;
-    } else {
-        return -1;
-    }
+    strncpy(name_res, client->GetClientControl()->fName, JACK_CLIENT_NAME_SIZE);
+    return 0;
 }
 
@@ -379,5 +371,4 @@
 int JackEngine::InternalClientUnload(int refnum, int* status)
 {
-    AssertRefnum(refnum);
     JackClientInterface* client = fClientTable[refnum];
     if (client) {
@@ -593,16 +584,10 @@
 int JackEngine::ClientExternalClose(int refnum)
 {
-    AssertRefnum(refnum);
     JackClientInterface* client = fClientTable[refnum];
-
-    if (client)	{
-        fEngineControl->fTransport.ResetTimebase(refnum);
-        int res = ClientCloseAux(refnum, client, true);
-        client->Close();
-        delete client;
-        return res;
-    } else {
-        return -1;
-    }
+    fEngineControl->fTransport.ResetTimebase(refnum);
+    int res = ClientCloseAux(refnum, client, true);
+    client->Close();
+    delete client;
+    return res;
 }
 
@@ -610,7 +595,6 @@
 int JackEngine::ClientInternalClose(int refnum, bool wait)
 {
-    AssertRefnum(refnum);
     JackClientInterface* client = fClientTable[refnum];
-    return (client)	? ClientCloseAux(refnum, client, wait) : -1;
+    return ClientCloseAux(refnum, client, wait);
 }
 
@@ -657,9 +641,7 @@
 int JackEngine::ClientActivate(int refnum, bool is_real_time)
 {
-    AssertRefnum(refnum);
     JackClientInterface* client = fClientTable[refnum];
-    assert(fClientTable[refnum]);
-
     jack_log("JackEngine::ClientActivate ref = %ld name = %s", refnum, client->GetClientControl()->fName);
+    
     if (is_real_time)
         fGraphManager->Activate(refnum);
@@ -678,9 +660,5 @@
 int JackEngine::ClientDeactivate(int refnum)
 {
-    AssertRefnum(refnum);
     JackClientInterface* client = fClientTable[refnum];
-    if (client == NULL)
-        return -1;
-
     jack_log("JackEngine::ClientDeactivate ref = %ld name = %s", refnum, client->GetClientControl()->fName);
 
@@ -718,7 +696,5 @@
 {
     jack_log("JackEngine::PortRegister ref = %ld name = %s type = %s flags = %d buffer_size = %d", refnum, name, type, flags, buffer_size);
-    AssertRefnum(refnum);
-    assert(fClientTable[refnum]);
-
+ 
     // Check if port name already exists
     if (fGraphManager->GetPort(name) != NO_PORT) {
@@ -739,7 +715,5 @@
 {
     jack_log("JackEngine::PortUnRegister ref = %ld port_index = %ld", refnum, port_index);
-    AssertRefnum(refnum);
-    assert(fClientTable[refnum]);
-
+ 
     // Disconnect port ==> notification is sent
     PortDisconnect(refnum, port_index, ALL_PORTS);
@@ -756,5 +730,4 @@
 {
     jack_log("JackEngine::PortConnect src = %s dst = %s", src, dst);
-    AssertRefnum(refnum);
     jack_port_id_t port_src, port_dst;
 
@@ -767,5 +740,4 @@
 {
     jack_log("JackEngine::PortConnect src = %d dst = %d", src, dst);
-    AssertRefnum(refnum);
     JackClientInterface* client;
     int ref;
@@ -803,5 +775,4 @@
 {
     jack_log("JackEngine::PortDisconnect src = %s dst = %s", src, dst);
-    AssertRefnum(refnum);
     jack_port_id_t port_src, port_dst;
 
@@ -814,6 +785,5 @@
 {
     jack_log("JackEngine::PortDisconnect src = %d dst = %d", src, dst);
-    AssertRefnum(refnum);
-
+ 
     if (dst == ALL_PORTS) {
 
@@ -851,5 +821,4 @@
 int JackEngine::PortRename(int refnum, jack_port_id_t port, const char* name)
 {
-    AssertRefnum(refnum);
     char old_name[JACK_CLIENT_NAME_SIZE + JACK_PORT_NAME_SIZE];
     strcpy(old_name, fGraphManager->GetPort(port)->GetName());
Index: /jack2/trunk/jackmp/common/JackEngineControl.cpp
===================================================================
--- /jack2/trunk/jackmp/common/JackEngineControl.cpp (revision 3526)
+++ /jack2/trunk/jackmp/common/JackEngineControl.cpp (revision 3901)
@@ -82,6 +82,7 @@
 }
     
-void JackEngineControl::NotifyXRun(float delayed_usecs)
+void JackEngineControl::NotifyXRun(jack_time_t callback_usecs, float delayed_usecs)
 {
+    ResetFrameTime(callback_usecs);
     fXrunDelayedUsecs = delayed_usecs;
     if (delayed_usecs > fMaxDelayedUsecs)
Index: /jack2/trunk/jackmp/common/JackEngine.h
===================================================================
--- /jack2/trunk/jackmp/common/JackEngine.h (revision 3853)
+++ /jack2/trunk/jackmp/common/JackEngine.h (revision 3901)
@@ -24,4 +24,5 @@
 #include "JackGraphManager.h"
 #include "JackSynchro.h"
+#include "JackMutex.h"
 #include "JackTransportEngine.h"
 #include "JackPlatformPlug.h"
@@ -38,6 +39,8 @@
 */
 
-class SERVER_EXPORT JackEngine 
+class SERVER_EXPORT JackEngine : public JackLockAble
 {
+    friend class JackLockedEngine;
+    
     private:
 
@@ -72,4 +75,9 @@
         void NotifyPortRename(jack_port_id_t src, const char* old_name);
         void NotifyActivate(int refnum);
+        
+        bool CheckClient(int refnum)
+        {
+            return (refnum >= 0 && refnum < CLIENT_NUM && fClientTable[refnum] != NULL);
+        }
 
     public:
Index: /jack2/trunk/jackmp/common/JackMutex.h
===================================================================
--- /jack2/trunk/jackmp/common/JackMutex.h (revision 2907)
+++ /jack2/trunk/jackmp/common/JackMutex.h (revision 3901)
@@ -37,9 +37,7 @@
 {
 
-    private:
-
+    protected:
+    
         JackMutex fMutex;
-
-    protected:
 
         JackLockAble()
Index: /jack2/trunk/jackmp/posix/JackPosixMutex.h
===================================================================
--- /jack2/trunk/jackmp/posix/JackPosixMutex.h (revision 3665)
+++ /jack2/trunk/jackmp/posix/JackPosixMutex.h (revision 3901)
@@ -104,9 +104,10 @@
         }
 
-        void Lock()
+        bool Lock()
         {
             int res = pthread_mutex_lock(&fMutex);
             if (res != 0)
                 jack_error("JackPosixMutex::Lock res = %d", res);
+            return (res == 0);
         }
 
@@ -116,9 +117,10 @@
         }
 
-        void Unlock()
+        bool Unlock()
         {
             int res = pthread_mutex_unlock(&fMutex);
             if (res != 0)
                 jack_error("JackPosixMutex::Unlock res = %d", res);
+            return (res == 0);
         }