IOSCSIBlockCommandsDevicePM.cpp   [plain text]

/*
 * Copyright (c) 1998-2002 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@
 */


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
//	Includes
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

// General IOKit headers
#include <IOKit/IOBufferMemoryDescriptor.h>
#include <IOKit/IOMessage.h>

// IOKit Power Management headers
#include <IOKit/pwr_mgt/RootDomain.h>

// SCSI Architecture Model Family includes
#include <IOKit/scsi-commands/SCSITask.h>
#include "IOSCSIBlockCommandsDevice.h"


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
//	Macros
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

#define DEBUG 									0
#define DEBUG_ASSERT_COMPONENT_NAME_STRING		"SBCPower"

#if DEBUG
#define SCSI_SBC_DEVICE_DEBUGGING_LEVEL			0
#endif


#include "IOSCSIArchitectureModelFamilyDebugging.h"


#define SCSI_SBC_DEVICE_DEBUGGING_LEVEL 0

#if ( SCSI_SBC_DEVICE_DEBUGGING_LEVEL >= 1 )
#define PANIC_NOW(x)		IOPanic x
#else
#define PANIC_NOW(x)
#endif

#if ( SCSI_SBC_DEVICE_DEBUGGING_LEVEL >= 2 )
#define ERROR_LOG(x)		IOLog x
#else
#define ERROR_LOG(x)
#endif

#if ( SCSI_SBC_DEVICE_DEBUGGING_LEVEL >= 3 )
#define STATUS_LOG(x)		IOLog x
#else
#define STATUS_LOG(x)
#endif


#define super IOSCSIPrimaryCommandsDevice


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
//	Constants
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

// We have 4 default power states. ACTIVE, IDLE, STANDBY, and SLEEP in order
// of most power to least power. In SLEEP, the Vcc can be removed, so we must
// trap for that in our power management code.

static IOPMPowerState sPowerStates[kSBCNumPowerStates] =
{
	{ kIOPMPowerStateVersion1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },			/* never entered voluntarily */
	{ kIOPMPowerStateVersion1, 0, IOPMPowerOn, IOPMPowerOn, 0, 0, 0, 0, 0, 0, 0, 0 },
	{ kIOPMPowerStateVersion1, (IOPMDeviceUsable | kIOPMPreventIdleSleep), IOPMPowerOn, IOPMPowerOn, 0, 0, 0, 0, 0, 0, 0, 0 },
	{ kIOPMPowerStateVersion1, (IOPMDeviceUsable | kIOPMPreventIdleSleep), IOPMPowerOn, IOPMPowerOn, 0, 0, 0, 0, 0, 0, 0, 0 },
	{ kIOPMPowerStateVersion1, (IOPMDeviceUsable | IOPMMaxPerformance | kIOPMPreventIdleSleep), IOPMPowerOn, IOPMPowerOn, 0, 0, 0, 0, 0, 0, 0, 0 }
};


// Static prototypes
static IOReturn
IOSCSIBlockCommandsDevicePowerDownHandler ( void * 			target,
											void * 			refCon,
											UInt32 			messageType,
											IOService * 	provider,
											void * 			messageArgument,
											vm_size_t 		argSize );


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ IOSCSIBlockCommandsDevicePowerDownHandler - C->C++ Glue code for Power
//												 Down Notifications.
//																	   [STATIC]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ


static IOReturn
IOSCSIBlockCommandsDevicePowerDownHandler ( void * 			target,
											void * 			refCon,
											UInt32 			messageType,
											IOService * 	provider,
											void * 			messageArgument,
											vm_size_t 		argSize )
{
	
	return ( ( IOSCSIBlockCommandsDevice * ) target )->PowerDownHandler (
														refCon,
														messageType,
														provider,
														messageArgument,
														argSize );
	
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ PowerDownHandler - Method called at sleep/restart/shutdown time.
//																	[PROTECTED]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

IOReturn
IOSCSIBlockCommandsDevice::PowerDownHandler (	void * 			refCon,
												UInt32 			messageType,
												IOService * 	provider,
												void * 			messageArgument,
												vm_size_t 		argSize )
{
	
	SCSIServiceResponse			serviceResponse = kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
	IOReturn					status 			= kIOReturnUnsupported;
	SCSITaskIdentifier			request			= NULL;
	
	switch ( messageType )
	{
		
		case kIOMessageSystemWillPowerOff:
			
			if ( ( fMediumPresent == true ) && ( fDeviceIsShared == false ) )
			{
				
				// Media is present (but may be spinning). Make sure the drive is spun down.
				if ( fCurrentPowerState > kSBCPowerStateSleep )
				{
					
					request = GetSCSITask ( );
					
					// Make sure the drive is spun down
					if ( START_STOP_UNIT ( request, 1, 0, 0, 0, 0 ) == true )
					{
						
						serviceResponse = SendCommand ( request, 0 );
						
					}
					
					// Give the drive some time to park the heads.
					IOSleep ( 500 );
					
					ReleaseSCSITask ( request );
					
				}
				
			}
			break;
			
		case kIOMessageSystemWillSleep:
		case kIOMessageSystemWillRestart:
		default:
			// We don't do anything at sleep or restart time here. That is handled via
			// standard power management functions. See HandlePowerChange() for more
			// information.
			break;
		
	}
	
	return status;
	
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ GetInitialPowerState - Asks the driver which power state the device is
//							in at startup time. This function is only called
//							once, right after InitializePowerManagement().
//																	[PROTECTED]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

UInt32
IOSCSIBlockCommandsDevice::GetInitialPowerState ( void )
{
	
	return kSBCPowerStateActive;
	
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ GetNumberOfPowerStateTransitions - Asks the driver for the number of state
//										transitions between sleep state and
//										the highest power state.	[PROTECTED]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

UInt32
IOSCSIBlockCommandsDevice::GetNumberOfPowerStateTransitions ( void )
{
    return ( kSBCPowerStateActive - kSBCPowerStateSleep );
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ InitializePowerManagement - 	Register the driver with our policy-maker
//									(also in the same class).		[PROTECTED]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

void
IOSCSIBlockCommandsDevice::InitializePowerManagement ( IOService * provider )
{
	
	fCurrentPowerState = kSBCPowerStateActive;
	
	// Call our super to get us into the power management tree
	super::InitializePowerManagement ( provider );
	
	// Register ourselves as a "policy maker" for this device. We use
	// the number of default power states defined by SBC-2.
	registerPowerDriver ( this, sPowerStates, kSBCNumPowerStates );
	
	// Install handler for shutdown notifications
	fPowerDownNotifier = registerPrioritySleepWakeInterest (
					( IOServiceInterestHandler ) IOSCSIBlockCommandsDevicePowerDownHandler,
					this );
	
	// Make sure we clamp the lowest power setting that we voluntarily go
	// into is state kSBCPowerStateSleep. We only enter kSBCPowerStateSystemSleep
	// if told by the power manager during a system sleep.
	changePowerStateTo ( kSBCPowerStateSleep );
	
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ HandleCheckPowerState - 	Checks to see if the power state is
//								kSBCPowerStateActive				[PROTECTED]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

void
IOSCSIBlockCommandsDevice::HandleCheckPowerState ( void )
{
	
	if ( IsDeviceAccessEnabled ( ) )
	{
		
		super::HandleCheckPowerState ( kSBCPowerStateActive );
		
	}
	
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ TicklePowerManager - 	Calls activityTickle to tell the power manager we
//							need to be in a certain state to fulfill I/O
//																	[PROTECTED]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

void
IOSCSIBlockCommandsDevice::TicklePowerManager ( void )
{
	
	// Tell the power manager we must be in active state to handle requests
	// "active" state means the minimal possible state in which the driver can
	// handle I/O. This may be set to standby, but there is no gain to setting
	// the drive to standby and then issuing an I/O, it just requires more time.
	// Also, if the drive was asleep, it might need a reset which could put it
	// in standby mode anyway, so we usually request the max state from the power
	// manager 
	( void ) super::TicklePowerManager ( kSBCPowerStateActive );
	
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ HandlePowerChange - Handles the state machine for power management
//																	[PROTECTED]
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

void
IOSCSIBlockCommandsDevice::HandlePowerChange ( void )
{
	
	SCSIServiceResponse		serviceResponse;
	SCSITaskIdentifier		request = NULL;
	
	STATUS_LOG ( ( "IOSCSIBlockCommandsDevice::HandlePowerChange called\n" ) );
	
	request = GetSCSITask ( );
	
	while ( ( fProposedPowerState != fCurrentPowerState ) && ( isInactive ( ) == false ) )
	{
		
		STATUS_LOG ( ( "fProposedPowerState = %ld, fCurrentPowerState = %ld\n",
						fProposedPowerState, fCurrentPowerState ) );

		if ( ( fCurrentPowerState <= kSBCPowerStateSleep ) &&
			 ( fProposedPowerState > kSBCPowerStateSleep ) )
		{
			
			STATUS_LOG ( ( "We think we're in sleep\n" ) );
			
			if ( fDeviceIsShared == false )	
			{		
				
				if ( START_STOP_UNIT ( request, 0x00, 0x00, 0x00, 0x01, 0x00 ) == true )
				{
					
					serviceResponse = SendCommand ( request, 0 );
					
				}
				
			}
			
			// First, if we were in sleep mode ( fCurrentPowerState <= kSBCPowerStateSleep )
			// then we need to do some stuff to recover the device. If power was pulled, we
			// need to clear the power-on reset sense data.
			STATUS_LOG ( ( "calling ClearPowerOnReset\n" ) );
			
			// /!\ WARNING! we may bail out of ClearPowerOnReset because
			// the device was hot unplugged while we were sleeping - do sanity check here
			// and break out of loop if we have been terminated.
			if ( ClearPowerOnReset ( ) == false )
				break;
			
			STATUS_LOG ( ( "calling ClearNotReadyStatus\n" ) );
			
			// /!\ WARNING! we may bail out of ClearNotReadyStatus because
			// the device was hot unplugged while we were sleeping - do sanity check here
			// and break out of loop if we have been terminated.
			if ( ClearNotReadyStatus ( ) == false )
				break;
			
			// Now, test if media is present, if so we lock it back in so the user
			// can't eject it, and if s/he removed the medium we notify the layer
			// above that the medium is gone and tear down the stack.
			if ( fMediaIsRemovable == true )
			{
				
				if ( fMediumPresent == true )
				{
					
					bool	mediaPresent = false;
					
					// Give the driver some lee-way in waking up because we think
					// media is actually there!
					for ( UInt32 index = 0; index < 100; index++ )
					{
						
						STATUS_LOG ( ( "Calling VerifyMediumPresence\n" ) );
						
						mediaPresent = VerifyMediumPresence ( );
						if ( mediaPresent )
							break;
						
						IOSleep ( 200 );
						
					}
					
					if ( mediaPresent != fMediumPresent )
					{
						PANIC_NOW ( ( "Unexpected Media Removal when waking up from sleep\n" ) );
					}
					
					else
					{
						
						fMediumRemovalPrevented = PreventMediumRemoval ( );
						if ( fMediumRemovalPrevented == false )
						{
							
							// Media is not locked into the drive, so this is most likely
							// a manually ejectable device, start polling for media removal.
							fPollingMode = kPollingMode_MediaRemoval;
							EnablePolling ( );
							
						}
						
					}
					
				}
				
				else
				{
 					
 					fPollingMode = kPollingMode_NewMedia;
					EnablePolling ( );
					
				}
				
			}
			
		}
		
		switch ( fProposedPowerState )
		{
			
			case kSBCPowerStateSystemSleep:
			{
				
				UInt32 previousPowerState;
				
				STATUS_LOG ( ( "case kSBCPowerStateSystemSleep\n" ) );
				
				// Immediately disable polling if we are currently polling
				// for media or for its removal.
				if ( fPollingMode != kPollingMode_Suspended )
				{
					
					STATUS_LOG ( ( "Disabling polling\n" ) );
					DisablePolling ( );
					
				}
				
				// let outstanding commands complete
				previousPowerState = fCurrentPowerState;
				fCurrentPowerState = fProposedPowerState;
				
				while ( fNumCommandsOutstanding > 1 )
				{
					
					// Sleep this thread for 1ms until all outstanding commands
					// have completed. This prevents a sleep command from entering
					// the queue before an I/O and causing a problem on wakeup.
					IOSleep ( 1 );
					
				}
							
				// If the device supports the power conditions mode page, and we haven't already
				// put it to sleep using the START_STOP_UNIT command, issue one to the drive.
				if ( previousPowerState != kSBCPowerStateSleep )
				{
					
					if ( fDeviceIsShared == false )
					{
						
						if ( fDeviceSupportsPowerConditions )
						{
						
							STATUS_LOG ( ( "Sending START_STOP_UNIT to drive to turn it off\n" ) );
							
							if ( START_STOP_UNIT ( request, 0, 0x05, 0, 0, 0 ) == true )
							{
								
								serviceResponse = SendCommand ( request, 0 );
								
							}
							
						}
										
						else
						{
		
							STATUS_LOG ( ( "Power conditions not supported, make sure drive is spun down\n" ) );
						
							// At a minimum, make sure the drive is spun down
							if ( START_STOP_UNIT ( request, 0, 0, 0, 0, 0 ) == true )
							{
								
								serviceResponse = SendCommand ( request, 0 );
								
							}
							
						}
						
					}
					
				}
				
				fCurrentPowerState = kSBCPowerStateSystemSleep;
				
			}	
			break;
			
			case kSBCPowerStateSleep:
			{
				
				STATUS_LOG ( ( "case kSBCPowerStateSleep\n" ) );
				
				// are we waking up from system sleep?
				if ( fCurrentPowerState < kSBCPowerStateSleep )
				{
					
					// If we have woken up from system sleep, the drive
					// should get a power on reset or a reset which will cause it
					// to truly be in active mode. We can simply tickle the power
					// manager here to bring us into active state and just pretend
					// we went back to sleep here.
					STATUS_LOG ( ( "TicklePowerManager.\n" ) );
					TicklePowerManager ( );
					STATUS_LOG ( ( "Wakeup path completed.\n" ) );

					fCurrentPowerState = fProposedPowerState;
					break;
					
				}
				
				if ( ( fCurrentPowerState > kSBCPowerStateSleep ) && ( fDeviceIsShared == false ) )
				{
					
					STATUS_LOG ( ( "At minimum, make sure drive is spun down.\n" ) );
					
					// At a minimum, make sure the drive is spun down
					if ( START_STOP_UNIT ( request, 0, 0, 0, 0, 0 ) == true )
					{
						
						serviceResponse = SendCommand ( request, 0 );
						
					}
					
				}
				
				fCurrentPowerState = kSBCPowerStateSleep;
				
			}
			break;
			
			case kSBCPowerStateStandby:
			{
				
				STATUS_LOG ( ( "case kSBCPowerStateStandby\n" ) );

				STATUS_LOG ( ( "At minimum, make sure drive is spun down.\n" ) );
				if ( ( fCurrentPowerState > kSBCPowerStateStandby ) && ( fDeviceIsShared == false ) )
				{
					
					// At a minimum, make sure the drive is spun down
					if ( START_STOP_UNIT ( request, 0, 0, 0, 0, 0 ) == true )
					{
						
						serviceResponse = SendCommand ( request, 0 );
						
					}
					
				}
				
				fCurrentPowerState = kSBCPowerStateStandby;
				
			}
			break;
			
			case kSBCPowerStateIdle:
			{
				
				STATUS_LOG ( ( "case kSBCPowerStateIdle\n" ) );				
				fCurrentPowerState = kSBCPowerStateIdle;
				
			}
			break;
			
			case kSBCPowerStateActive:
			{
				
				STATUS_LOG ( ( "case kSBCPowerStateActive\n" ) );
				
				if ( fDeviceIsShared == false )
				{
					
					if ( START_STOP_UNIT ( request, 0, 0, 0, 1, 0 ) == true )
					{
						
						serviceResponse = SendCommand ( request, 0 );
						
					}
					
				}
				
				fCurrentPowerState = kSBCPowerStateActive;
				fCommandGate->commandWakeup ( &fCurrentPowerState, false );
				
			}
			break;
			
			default:
				PANIC_NOW ( ( "Undefined power state issued\n" ) );
				break;
			
		}
		
	}

	if ( isInactive ( ) )
	{
		
		fCurrentPowerState = fProposedPowerState;
		fCommandGate->commandWakeup ( &fCurrentPowerState, false );
		
	}
	
	ReleaseSCSITask ( request );
	
}


//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ
// ₯ VerifyMediumPresence - Checks if media is present. If so, it locks it down
//							again, else it requests a dialog to be displayed
//							and tears the stack down
//ΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡΡ

bool
IOSCSIBlockCommandsDevice::VerifyMediumPresence ( void )
{
	
	SCSI_Sense_Data				senseBuffer		= { 0 };
	IOMemoryDescriptor *		bufferDesc		= NULL;
	SCSITaskIdentifier			request			= NULL;
	bool						mediaPresent	= false;
	bool						driveReady 		= false;
	SCSIServiceResponse 		serviceResponse = kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;
	
	STATUS_LOG ( ( "%s::%s called\n", getName ( ), __FUNCTION__ ) );
	
	bufferDesc = IOMemoryDescriptor::withAddress ( ( void * ) &senseBuffer,
													kSenseDefaultSize,
													kIODirectionIn );
	
	require_nonzero ( bufferDesc, ErrorExit );
	
	request = GetSCSITask ( );
	require_nonzero ( request, ReleaseDescriptor );
	
	do
	{
		
		if ( TEST_UNIT_READY ( request, 0 ) == true )
	    {
			
	    	// The command was successfully built, now send it
	    	serviceResponse = SendCommand ( request, 0 );
	    	
		}
		
		if ( serviceResponse == kSCSIServiceResponse_TASK_COMPLETE )
		{
			
			bool validSense = false;
			
			if ( GetTaskStatus ( request ) == kSCSITaskStatus_CHECK_CONDITION )
			{
				
				validSense = GetAutoSenseData ( request, &senseBuffer );
				if ( validSense == false )
				{
					
					if ( REQUEST_SENSE ( request, bufferDesc, kSenseDefaultSize, 0  ) == true )
				    {
				    	
				    	// The command was successfully built, now send it
				    	serviceResponse = SendCommand ( request, 0 );
				    	
					}
					
					if ( serviceResponse == kSCSIServiceResponse_TASK_COMPLETE )
					{
						
						validSense = true;
						
					}
					
				}
				
				if ( validSense == true )
				{
					
					STATUS_LOG ( ( "sense data: %01x, %02x, %02x\n",
								( senseBuffer.SENSE_KEY  & kSENSE_KEY_Mask ),
								  senseBuffer.ADDITIONAL_SENSE_CODE,
								  senseBuffer.ADDITIONAL_SENSE_CODE_QUALIFIER ) );

					// Check the sense key to see if it is an error group we know how to handle
					if  ( ( ( senseBuffer.SENSE_KEY & kSENSE_KEY_Mask ) == kSENSE_KEY_NOT_READY ) || 
						  ( ( senseBuffer.SENSE_KEY & kSENSE_KEY_Mask ) == kSENSE_KEY_MEDIUM_ERROR ) )
					{
						
						// The SenseKey is an 02 ( Not Ready ) or 03 ( Medium Error ). Check to see
						// if we can do something about this
						
						if ( ( senseBuffer.ADDITIONAL_SENSE_CODE == 0x04 ) && 
							 ( senseBuffer.ADDITIONAL_SENSE_CODE_QUALIFIER == 0x02 ) )
						{
							
							// Device requires a start command before we can tell if media is there
							if ( START_STOP_UNIT ( request, 0x00, 0x00, 0x00, 0x01, 0x00 ) == true )
							{
								
								STATUS_LOG ( ( "Sending START_STOP_UNIT.\n" ) );
								serviceResponse = SendCommand ( request, 0 );
								
							}
							
							STATUS_LOG ( ( "%s::drive NOT READY\n", getName ( ) ) );
							
							IOSleep ( 200 );
							continue;
							
						}
						
						else if ( ( senseBuffer.ADDITIONAL_SENSE_CODE == 0x3A ) && 
							 	  ( senseBuffer.ADDITIONAL_SENSE_CODE_QUALIFIER == 0x00 ) )
						{
							
							STATUS_LOG ( ( "No Media.\n" ) );
							// No media is present, return false
							driveReady = true;
							mediaPresent = false;
							
						}
						
						else
						{
							
							STATUS_LOG ( ( "%s::drive NOT READY\n", getName ( ) ) );
							IOSleep ( 200 );
							continue;
							
						}
						
					}
					
					else
					{
						
						STATUS_LOG ( ( "%s::drive READY, media present\n", getName ( ) ) );
						// Media is present, return true
						driveReady = true;
						mediaPresent = true;
						
					}
					
				}
				
			}
			
			else
			{
				
				STATUS_LOG ( ( "%s::drive READY, media present\n", getName ( ) ) );
				// Media is present, return true
				driveReady = true;
				mediaPresent = true;
				
			}
			
		}
		
        else
        {
			
			// The command failed. Let's wait a bit and try again.
			IOSleep ( 200 );
			
		}
		
	// check isInactive in case device was hot unplugged during sleep
	// and we are in an infinite loop here
	} while ( ( driveReady == false ) && ( isInactive ( ) == false ) );
	
	ReleaseSCSITask ( request );
	
	
ReleaseDescriptor:
	
	
	require_nonzero ( bufferDesc, ErrorExit );
	bufferDesc->release ( );	
	bufferDesc = NULL;
	
	
ErrorExit:
	
	
	return mediaPresent;
	
}