--- /dev/null
+++ xnu/xnu-792.25.20/iokit/Kernel/IOPMPowerStateQueue.cpp
@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2001-2002 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
+ *
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+ 
+#include "IOPMPowerStateQueue.h"
+#include "IOKit/IOLocks.h"
+#undef super
+#define super IOEventSource
+OSDefineMetaClassAndStructors(IOPMPowerStateQueue, IOEventSource);
+
+#ifdef __i386__ /* ppc does this right and doesn't need these routines */
+static
+void *	OSDequeueAtomic(void ** inList, SInt32 inOffset)
+{
+	void *	oldListHead;
+	void *	newListHead;
+
+	do {
+		oldListHead = *inList;
+		if (oldListHead == NULL) {
+			break;
+		}
+		
+		newListHead = *(void **) (((char *) oldListHead) + inOffset);
+	} while (! OSCompareAndSwap((UInt32)oldListHead,
+					(UInt32)newListHead, (UInt32 *)inList));
+	return oldListHead;
+}
+
+static
+void	OSEnqueueAtomic(void ** inList, void * inNewLink, SInt32 inOffset)
+{
+	void *	oldListHead;
+	void *	newListHead = inNewLink;
+	void **	newLinkNextPtr = (void **) (((char *) inNewLink) + inOffset);
+
+	do {
+		oldListHead = *inList;
+		*newLinkNextPtr = oldListHead;
+	} while (! OSCompareAndSwap((UInt32)oldListHead, (UInt32)newListHead,
+					(UInt32 *)inList));
+}
+#endif /* __i386__ */
+
+
+IOPMPowerStateQueue *IOPMPowerStateQueue::PMPowerStateQueue(OSObject *inOwner)
+{
+    IOPMPowerStateQueue     *me = new IOPMPowerStateQueue;
+
+    if(me && !me->init(inOwner, 0) )
+    {
+        me->release();
+        return NULL;
+    }
+
+    return me;
+}
+
+bool IOPMPowerStateQueue::init(OSObject *owner, Action action)
+{
+    if(!(super::init(owner, (IOEventSource::Action) action))) return false;
+
+    // Queue of powerstate changes
+    changes = NULL;
+#ifdef __i386__
+    if (!(tmpLock = IOLockAlloc()))  panic("IOPMPowerStateQueue::init can't alloc lock");
+#endif
+    return true;
+}
+
+
+bool IOPMPowerStateQueue::unIdleOccurred(IOService *inTarget, unsigned long inState)
+{
+    PowerChangeEntry             *new_one = NULL;
+
+    new_one = (PowerChangeEntry *)IOMalloc(sizeof(PowerChangeEntry));
+    if(!new_one) return false;
+    
+    new_one->actionType = IOPMPowerStateQueue::kUnIdle;
+    new_one->state = inState;
+    new_one->target = inTarget;
+    
+    // Change to queue
+#ifdef __i386__
+    IOLockLock(tmpLock);
+#endif
+    OSEnqueueAtomic((void **)&changes, (void *)new_one, 0);
+#ifdef __i386__
+    IOLockUnlock(tmpLock);
+#endif
+    signalWorkAvailable();
+
+    return true;
+}
+
+// checkForWork() is called in a gated context
+bool IOPMPowerStateQueue::checkForWork()
+{
+    PowerChangeEntry            *theNode;
+    int                         theState;
+    IOService                   *theTarget;
+    UInt16                      theAction;
+    
+    // Dequeue and process the state change request
+#ifdef __i386__
+    IOLockLock(tmpLock);
+#endif
+    if((theNode = (PowerChangeEntry *)OSDequeueAtomic((void **)&changes, 0)))
+    {
+#ifdef __i386__
+      IOLockUnlock(tmpLock);
+#endif
+        theState = theNode->state;
+        theTarget = theNode->target;
+        theAction = theNode->actionType;
+        IOFree((void *)theNode, sizeof(PowerChangeEntry));
+        
+        switch (theAction)
+        {
+            case kUnIdle:
+                theTarget->command_received((void *)theState, 0, 0, 0);
+                break;
+        }
+    }
+#ifdef __i386__
+    else {
+      IOLockUnlock(tmpLock);
+    }
+#endif
+    // Return true if there's more work to be done
+    if(changes) return true;
+    else return false;
+}