--- xnu/xnu-1504.7.4/iokit/Kernel/IOKitDebug.cpp
+++ xnu/xnu-1699.26.8/iokit/Kernel/IOKitDebug.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1998-2010 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -25,14 +25,11 @@
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-/*
- * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
- *
- * HISTORY
- *
- */
 
 #include <sys/sysctl.h>
+
+#include <libkern/c++/OSContainers.h>
+#include <libkern/c++/OSCPPDebug.h>
 
 #include <IOKit/IOKitDebug.h>
 #include <IOKit/IOLib.h>
@@ -40,9 +37,6 @@
 #include <IOKit/IODeviceTreeSupport.h>
 #include <IOKit/IOService.h>
 
-#include <libkern/c++/OSContainers.h>
-#include <libkern/c++/OSCPPDebug.h>
-
 #ifdef IOKITDEBUG
 #define DEBUG_INIT_VALUE IOKITDEBUG
 #else
@@ -50,7 +44,10 @@
 #endif
 
 SInt64		gIOKitDebug = DEBUG_INIT_VALUE;
-SYSCTL_QUAD(_debug, OID_AUTO, iokit, CTLFLAG_RW, &gIOKitDebug, "boot_arg io");
+SInt64		gIOKitTrace = 0;
+
+SYSCTL_QUAD(_debug, OID_AUTO, iokit, CTLFLAG_RW | CTLFLAG_LOCKED, &gIOKitDebug, "boot_arg io");
+SYSCTL_QUAD(_debug, OID_AUTO, iotrace, CTLFLAG_RW | CTLFLAG_LOCKED, &gIOKitTrace, "trace io");
 
 
 int 		debug_malloc_size;
@@ -101,7 +98,7 @@
     iter->release();
 }
 
-void dbugprintf(char *fmt, ...);
+void dbugprintf(const char *fmt, ...);
 void db_dumpiojunk( const IORegistryPlane * plane );
 
 void db_piokjunk(void) {