Index: /trunk/src/VBox/VMM/VMMR3/PDM.cpp
===================================================================
--- /trunk/src/VBox/VMM/VMMR3/PDM.cpp	(revision 40957)
+++ /trunk/src/VBox/VMM/VMMR3/PDM.cpp	(revision 40958)
@@ -417,6 +417,6 @@
              * Register the info handlers.
              */
-            DBGFR3InfoRegisterInternal(pVM, "pdmtracingids", 
-                                       "Displays the tracing IDs assigned by PDM to devices, USB device, drivers and more.", 
+            DBGFR3InfoRegisterInternal(pVM, "pdmtracingids",
+                                       "Displays the tracing IDs assigned by PDM to devices, USB device, drivers and more.",
                                        pdmR3InfoTracingIds);
 
@@ -2675,9 +2675,9 @@
 /**
  * Info handler for 'pdmtracingids'.
- * 
+ *
  * @param   pVM         The VM handle.
  * @param   pHlp        The output helpers.
  * @param   pszArgs     The optional user arguments.
- * 
+ *
  * @remarks Can be called on most threads.
  */
@@ -2687,5 +2687,6 @@
      * Parse the argument (optional).
      */
-    if (   *pszArgs
+    if (   pszArgs
+        && *pszArgs
         && strcmp(pszArgs, "all")
         && strcmp(pszArgs, "devices")
@@ -2696,10 +2697,10 @@
         return;
     }
-    bool fAll     = !*pszArgs || !strcmp(pszArgs, "all");
+    bool fAll     = !pszArgs || !*pszArgs || !strcmp(pszArgs, "all");
     bool fDevices = fAll || !strcmp(pszArgs, "devices");
     bool fUsbDevs = fAll || !strcmp(pszArgs, "usb");
     bool fDrivers = fAll || !strcmp(pszArgs, "drivers");
 
-    /* 
+    /*
      * Produce the requested output.
      */
@@ -2731,6 +2732,6 @@
                 uint32_t iLevel = 0;
                 for (PPDMDRVINS pDrvIns = pLun->pTop; pDrvIns; pDrvIns = pDrvIns->Internal.s.pDown, iLevel++)
-                    pHlp->pfnPrintf(pHlp, "%05u  %s (level %u, lun %u, dev %s)\n", 
-                                    pDrvIns->idTracing, pDrvIns->Internal.s.pDrv->pReg->szName, 
+                    pHlp->pfnPrintf(pHlp, "%05u  %s (level %u, lun %u, dev %s)\n",
+                                    pDrvIns->idTracing, pDrvIns->Internal.s.pDrv->pReg->szName,
                                     iLevel, pLun->iLun, pDevIns->Internal.s.pDevR3->pReg->szName);
             }
@@ -2743,6 +2744,6 @@
                 uint32_t iLevel = 0;
                 for (PPDMDRVINS pDrvIns = pLun->pTop; pDrvIns; pDrvIns = pDrvIns->Internal.s.pDown, iLevel++)
-                    pHlp->pfnPrintf(pHlp, "%05u  %s (level %u, lun %u, dev %s)\n", 
-                                    pDrvIns->idTracing, pDrvIns->Internal.s.pDrv->pReg->szName, 
+                    pHlp->pfnPrintf(pHlp, "%05u  %s (level %u, lun %u, dev %s)\n",
+                                    pDrvIns->idTracing, pDrvIns->Internal.s.pDrv->pReg->szName,
                                     iLevel, pLun->iLun, pUsbIns->Internal.s.pUsbDev->pReg->szName);
             }