--- xnu/xnu-1228/iokit/Kernel/IOKitDebug.cpp
+++ xnu/xnu-1504.15.3/iokit/Kernel/IOKitDebug.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1998-2011 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -25,12 +25,6 @@
  * 
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-/*
- * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
- *
- * HISTORY
- *
- */
 
 #include <sys/sysctl.h>
 
@@ -50,7 +44,12 @@
 #endif
 
 SInt64		gIOKitDebug = DEBUG_INIT_VALUE;
-SYSCTL_QUAD(_debug, OID_AUTO, iokit, CTLFLAG_RW, &gIOKitDebug, "boot_arg io");
+SInt64		gIOKitTrace = 0x3B;
+UInt64		gIOInterruptThresholdNS = 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");
+SYSCTL_QUAD(_debug, OID_AUTO, iointthreshold, CTLFLAG_RW | CTLFLAG_LOCKED, &gIOInterruptThresholdNS, "io interrupt threshold");
 
 
 int 		debug_malloc_size;
@@ -62,6 +61,11 @@
 
 extern "C" {
 
+#if 0
+#define DEBG(fmt, args...)   { kprintf(fmt, ## args); }
+#else
+#define DEBG(fmt, args...)   { IOLog(fmt, ## args); }
+#endif
 
 void IOPrintPlane( const IORegistryPlane * plane )
 {
@@ -75,23 +79,23 @@
     assert( iter );
     all = iter->iterateAll();
     if( all) {
-        IOLog("Count %d\n", all->getCount() );
+        DEBG("Count %d\n", all->getCount() );
         all->release();
     } else
-	IOLog("Empty\n");
+	DEBG("Empty\n");
 
     iter->reset();
     while( (next = iter->getNextObjectRecursive())) {
 	snprintf(format + 1, sizeof(format) - 1, "%ds", 2 * next->getDepth( plane ));
-	IOLog( format, "");
-	IOLog( "\033[33m%s", next->getName( plane ));
+	DEBG( format, "");
+	DEBG( "\033[33m%s", next->getName( plane ));
 	if( (next->getLocation( plane )))
-            IOLog("@%s", next->getLocation( plane ));
-	IOLog("\033[0m <class %s", next->getMetaClass()->getClassName());
+            DEBG("@%s", next->getLocation( plane ));
+	DEBG("\033[0m <class %s", next->getMetaClass()->getClassName());
         if( (service = OSDynamicCast(IOService, next)))
-            IOLog(", busy %ld", service->getBusyState());
-	IOLog( ">\n");
-	IOSleep(250);
+            DEBG(", busy %ld", (long) service->getBusyState());
+	DEBG( ">\n");
+//	IOSleep(250);
     }
     iter->release();
 }