示例#1
0
IOReturn CLASS::UIMCreateInterruptTransfer(IOUSBCommand* command)
{
    IOUSBCompletion comp;
    IOMemoryDescriptor* md;
    USBDeviceAddress addr;
    IODMACommand* dmac;
    uint32_t speed, tag;

    if (!command)
        return kIOReturnBadArgument;
    addr = command->GetAddress();
    if (addr == _hub3Address || addr == _hub2Address) {
        comp = command->GetUSLCompletion();
        dmac = command->GetDMACommand();
        if (dmac && dmac->getMemoryDescriptor())
            dmac->clearMemoryDescriptor();
        if (command->GetEndpoint() == 1U) {
            md = command->GetBuffer();
            if (!md)
                return kIOReturnInternalError;
            speed = (addr == _hub3Address ? kUSBDeviceSpeedSuper : kUSBDeviceSpeedHigh);
            tag = ((static_cast<uint32_t>(addr) << kUSBAddress_Shift) & kUSBAddress_Mask);
            tag |= ((speed << kUSBSpeed_Shift) & kUSBSpeed_Mask);
            md->setTag(tag);
            return RootHubQueueInterruptRead(md, static_cast<uint32_t>(command->GetReqCount()), comp);
        } else {
            Complete(comp, kIOUSBEndpointNotFound, static_cast<uint32_t>(command->GetReqCount()));
            return kIOUSBEndpointNotFound;
        }
    }
    return CreateTransfer(command, 0U);
}
AppleEHCIitdMemoryBlock*
AppleEHCIitdMemoryBlock::NewMemoryBlock(void)
{
    AppleEHCIitdMemoryBlock 	*me = new AppleEHCIitdMemoryBlock;
    IOByteCount					len;
	IODMACommand				*dmaCommand = NULL;
	UInt64						offset = 0;
	IODMACommand::Segment32		segments;
	UInt32						numSegments = 1;
	IOReturn					status = kIOReturnSuccess;
    
    if (me)
	{
		// Use IODMACommand to get the physical address
		dmaCommand = IODMACommand::withSpecification(kIODMACommandOutputHost32, 32, PAGE_SIZE, (IODMACommand::MappingOptions)(IODMACommand::kMapped | IODMACommand::kIterateOnly));
		if (!dmaCommand)
		{
			USBError(1, "AppleEHCIitdMemoryBlock::NewMemoryBlock - could not create IODMACommand");
			return NULL;
		}
		USBLog(6, "AppleEHCIitdMemoryBlock::NewMemoryBlock - got IODMACommand %p", dmaCommand);
		
		// allocate one page on a page boundary below the 4GB line
		me->_buffer = IOBufferMemoryDescriptor::inTaskWithPhysicalMask(kernel_task, kIOMemoryUnshared | kIODirectionInOut, kEHCIPageSize, kEHCIStructureAllocationPhysicalMask);
		
		// allocate exactly one physical page
		if (me->_buffer) 
		{
			status = me->_buffer->prepare();
			if (status)
			{
				USBError(1, "AppleEHCIitdMemoryBlock::NewMemoryBlock - could not prepare buffer");
				me->_buffer->release();
				me->_buffer = NULL;
				me->release();
				dmaCommand->release();
				return NULL;
			}
			me->_sharedLogical = (EHCIIsochTransferDescriptorSharedPtr)me->_buffer->getBytesNoCopy();
			bzero(me->_sharedLogical, kEHCIPageSize);
			status = dmaCommand->setMemoryDescriptor(me->_buffer);
			if (status)
			{
				USBError(1, "AppleEHCIitdMemoryBlock::NewMemoryBlock - could not set memory descriptor");
				me->_buffer->complete();
				me->_buffer->release();
				me->_buffer = NULL;
				me->release();
				dmaCommand->release();
				return NULL;
			}
			status = dmaCommand->gen32IOVMSegments(&offset, &segments, &numSegments);
			dmaCommand->clearMemoryDescriptor();
			dmaCommand->release();
			if (status || (numSegments != 1) || (segments.fLength != kEHCIPageSize))
			{
				USBError(1, "AppleEHCIitdMemoryBlock::NewMemoryBlock - could not get physical segment");
				me->_buffer->complete();
				me->_buffer->release();
				me->_buffer = NULL;
				me->release();
				return NULL;
			}
			me->_sharedPhysical = segments.fIOVMAddr;
		}
		else
		{
			USBError(1, "AppleEHCIitdMemoryBlock::NewMemoryBlock, could not allocate buffer!");
			me->release();
			me = NULL;
		}
	}
	else
	{
		USBError(1, "AppleEHCIitdMemoryBlock::NewMemoryBlock, constructor failed!");
    }
    return me;
}
示例#3
0
IOReturn AppleSamplePCI::generateDMAAddresses( IOMemoryDescriptor * memDesc )
{
    // Get the physical segment list. These could be used to generate a scatter gather
    // list for hardware.

    // This is the old getPhysicalSegment() loop calling IOMemoryDescriptor,
    // it will fail (panic) on new machines with memory above the 4Gb line

    IODMACommand *	cmd;
    IOReturn            err = kIOReturnSuccess;
    IOByteCount		offset = 0;
    IOPhysicalAddress	physicalAddr;
    IOPhysicalLength	segmentLength;
    UInt32              index = 0;

    while( (physicalAddr = memDesc->getPhysicalSegment( offset, &segmentLength ))) {
	IOLog("Physical segment(%ld) %08lx:%08lx\n", index, physicalAddr, segmentLength);
	offset += segmentLength;
	index++;
    }

    // 64 bit physical address generation using IODMACommand
    do
    {
	cmd = IODMACommand::withSpecification(
	    // outSegFunc - Host endian since we read the address data with the cpu
	    // and 64 bit wide quantities
	    kIODMACommandOutputHost64, 
	    // numAddressBits
	    64, 
	    // maxSegmentSize - zero for unrestricted physically contiguous chunks
	    0,
	    // mappingOptions - kMapped for DMA addresses
	    IODMACommand::kMapped,
	    // maxTransferSize - no restriction
	    0,
	    // alignment - no restriction
	    1 );
	if (!cmd)
	{
	    IOLog("IODMACommand::withSpecification failed\n");
	    break;
	}

	// point at the memory descriptor and use the auto prepare option
	// to prepare the entire range
	err = cmd->setMemoryDescriptor(memDesc);
	if (kIOReturnSuccess != err)
	{
	    IOLog("setMemoryDescriptor failed (0x%x)\n", err);
	    break;
	}

	UInt64 offset = 0;
	while ((kIOReturnSuccess == err) && (offset < memDesc->getLength()))
	{
	    // use the 64 bit variant to match outSegFunc
	    IODMACommand::Segment64 segments[1];
	    UInt32 numSeg = 1;

	    // use the 64 bit variant to match outSegFunc
	    err = cmd->gen64IOVMSegments(&offset, &segments[0], &numSeg);
	    IOLog("gen64IOVMSegments(%x) addr 0x%qx, len 0x%qx, nsegs %ld\n",
		    err, segments[0].fIOVMAddr, segments[0].fLength, numSeg);
	}

	// if we had a DMA controller, kick off the DMA here

	// when the DMA has completed,
	
	// clear the memory descriptor and use the auto complete option
	// to complete the transaction
	err = cmd->clearMemoryDescriptor();
	if (kIOReturnSuccess != err)
	{
	    IOLog("clearMemoryDescriptor failed (0x%x)\n", err);
	}
    }
    while (false);
    if (cmd)
	cmd->release();
    // end 64 bit loop


    // 32 bit physical address generation using IODMACommand
    // any memory above 4Gb in the memory descriptor will be buffered
    // to memory below the 4G line, on machines without remapping HW support
    do
    {
	cmd = IODMACommand::withSpecification(
	    // outSegFunc - Host endian since we read the address data with the cpu
	    // and 32 bit wide quantities
	    kIODMACommandOutputHost32, 
	    // numAddressBits
	    32, 
	    // maxSegmentSize - zero for unrestricted physically contiguous chunks
	    0,
	    // mappingOptions - kMapped for DMA addresses
	    IODMACommand::kMapped,
	    // maxTransferSize - no restriction
	    0,
	    // alignment - no restriction
	    1 );
	if (!cmd)
	{
	    IOLog("IODMACommand::withSpecification failed\n");
	    break;
	}

	// point at the memory descriptor and use the auto prepare option
	// to prepare the entire range
	err = cmd->setMemoryDescriptor(memDesc);
	if (kIOReturnSuccess != err)
	{
	    IOLog("setMemoryDescriptor failed (0x%x)\n", err);
	    break;
	}

	UInt64 offset = 0;
	while ((kIOReturnSuccess == err) && (offset < memDesc->getLength()))
	{
	    // use the 32 bit variant to match outSegFunc
	    IODMACommand::Segment32 segments[1];
	    UInt32 numSeg = 1;

	    // use the 32 bit variant to match outSegFunc
	    err = cmd->gen32IOVMSegments(&offset, &segments[0], &numSeg);
	    IOLog("gen32IOVMSegments(%x) addr 0x%lx, len 0x%lx, nsegs %ld\n",
		    err, segments[0].fIOVMAddr, segments[0].fLength, numSeg);
	}

	// if we had a DMA controller, kick off the DMA here

	// when the DMA has completed,
	
	// clear the memory descriptor and use the auto complete option
	// to complete the transaction
	err = cmd->clearMemoryDescriptor();
	if (kIOReturnSuccess != err)
	{
	    IOLog("clearMemoryDescriptor failed (0x%x)\n", err);
	}
    }
    while (false);
    if (cmd)
	cmd->release();
    // end 32 bit loop

    return (err);
}
static void 
DisjointCompletion(IOUSBController *me, IOUSBCommand *command, IOReturn status, UInt32 bufferSizeRemaining)
{
    IOBufferMemoryDescriptor	*buf = NULL;
	IODMACommand				*dmaCommand = NULL;

	USBTrace_Start( kUSBTController, kTPControllerDisjointCompletion, (uintptr_t)me, (uintptr_t)command, status, bufferSizeRemaining );
	
    if (!me || !command)
    {
		USBError(1, "DisjointCompletion sanity check failed - me(%p) command (%p)", me, command);
		return;
    }
	
	buf = OSDynamicCast(IOBufferMemoryDescriptor, command->GetBuffer());
	dmaCommand = command->GetDMACommand();
	
	if (!dmaCommand || !buf)
	{
		USBLog(1, "%s[%p]::DisjointCompletion - no dmaCommand, or buf(%p) is not an IOBMD", me->getName(), me, command->GetBuffer());
		USBTrace( kUSBTController, kTPControllerDisjointCompletion, (uintptr_t)me, (uintptr_t)command->GetBuffer(), 0, 1 );
		return;
	}
	
	if (dmaCommand->getMemoryDescriptor())
	{
		if (dmaCommand->getMemoryDescriptor() != buf)
		{
			USBLog(1, "%s[%p]::DisjointCompletion - buf(%p) doesn't match getMemoryDescriptor(%p)", me->getName(), me, buf, dmaCommand->getMemoryDescriptor());
			USBTrace( kUSBTController, kTPControllerDisjointCompletion, (uintptr_t)me, (uintptr_t)buf, (uintptr_t)dmaCommand->getMemoryDescriptor(), 2 );
		}
		
		// need to complete the dma command
		USBLog(6, "%s[%p]::DisjointCompletion - clearing memory descriptor (%p) from dmaCommand (%p)", me->getName(), me, dmaCommand->getMemoryDescriptor(), dmaCommand);
		dmaCommand->clearMemoryDescriptor();
	}
	
    if (command->GetDirection() == kUSBIn)
    {
		USBLog(5, "%s[%p]::DisjointCompletion, copying %d out of %d bytes to desc %p from buffer %p", me->getName(), me, (int)(command->GetDblBufLength()-bufferSizeRemaining), (int)command->GetDblBufLength(), command->GetOrigBuffer(), buf);
		command->GetOrigBuffer()->writeBytes(0, buf->getBytesNoCopy(), (command->GetDblBufLength()-bufferSizeRemaining));
    }
	
    buf->complete();
	buf->release();								// done with this buffer
	command->SetBuffer(NULL);
	
    // now call through to the original completion routine
    IOUSBCompletion completion = command->GetDisjointCompletion();
	
	if ( !command->GetIsSyncTransfer() )
	{
		// Free our command now that we have the completion and we are not going to use it anymore
		me->ReturnUSBCommand(command);
	}
	
   	if (completion.action)
	{
		USBLog(status == kIOReturnSuccess ? 7 : 3, "%s[%p]::DisjointCompletion calling through to %p - status 0x%x!", me->getName(), me, completion.action, (uint32_t)status);
		(*completion.action)(completion.target, completion.parameter, status, bufferSizeRemaining);
	}
	
	USBTrace_End( kUSBTController, kTPControllerDisjointCompletion, (uintptr_t)completion.target, (uintptr_t)completion.parameter, status, bufferSizeRemaining);
}
IOReturn 
IOUSBController::IsocIO(IOMemoryDescriptor *			buffer,
						UInt64							frameStart,
						UInt32							numFrames,
						IOUSBLowLatencyIsocFrame *		frameList,
						USBDeviceAddress				address,
						Endpoint *						endpoint,
						IOUSBLowLatencyIsocCompletion * completion,
						UInt32							updateFrequency)
{
    IOReturn				err = kIOReturnSuccess;
    IOUSBIsocCommand *		command = NULL;
    bool					crossEndianRequest = false;
	IODMACommand *			dmaCommand = NULL;
	bool					syncTransfer = false;
    
	// Validate the completion
	//
	USBLog(7, "%s[%p]::IsocIO(LL)", getName(), this);
	if (completion == 0)
	{
		USBLog(1, "%s[%p]::IsocIO(LL) - No completion.  Returning kIOReturnNoCompletion(0x%x)", getName(), this, kIOReturnNoCompletion);
		USBTrace( kUSBTController, kTPIsocIOLL, (uintptr_t)this, kIOReturnNoCompletion, 0, 3 );		
		return kIOReturnNoCompletion;
	}
	
	// Validate the commandGate
	//
	if (_commandGate == 0)
	{
		USBLog(1, "%s[%p]::IsocIO(LL) - Could not get _commandGate.  Returning kIOReturnInternalError(0x%x)", getName(), this, kIOReturnInternalError);
		USBTrace( kUSBTController, kTPIsocIOLL, (uintptr_t)this, kIOReturnInternalError, 0, 4 );
		return kIOReturnInternalError;
	}
	
	// If the high order bit of the endpoint transfer type is set, then this means it's a request from an Rosetta client
	if ( endpoint->direction & 0x80 )
	{
		endpoint->direction &= ~0x80;
		crossEndianRequest = true;
	}
	
	// Validate the direction of the endpoint -- it has to be kUSBIn or kUSBOut
	if ( (endpoint->direction != kUSBOut) && ( endpoint->direction != kUSBIn) )
	{		
		USBLog(1, "%s[%p]::IsocIO(LL) - Direction is not kUSBOut or kUSBIn (%d).  Returning kIOReturnBadArgument(0x%x)", getName(), this, endpoint->direction, kIOReturnBadArgument);
		USBTrace( kUSBTController, kTPIsocIOLL, (uintptr_t)this, endpoint->direction, kIOReturnBadArgument, 6 );
		return kIOReturnBadArgument;
	}
	
    if ( (uintptr_t)completion->action == (uintptr_t)&IOUSBSyncIsoCompletion )
	{
		syncTransfer = true;
        if ( _workLoop->onThread() )
        {
            USBError(1,"IOUSBController(%s)[%p]::DoIsocTransfer sync request on workloop thread.  Use async!", getName(), this);
            return kIOUSBSyncRequestOnWLThread;
        }
		
	}
	
	command = (IOUSBIsocCommand *)_freeUSBIsocCommandPool->getCommand(false);
    // If we couldn't get a command, increase the allocation and try again
    //
    if ( command == NULL )
    {
        IncreaseIsocCommandPool();
        
        command = (IOUSBIsocCommand *)_freeUSBIsocCommandPool->getCommand(false);
        if ( command == NULL )
        {
            USBLog(1, "%s[%p]::IsocIO(LL) Could not get a IOUSBIsocCommand", getName(), this);
			USBTrace( kUSBTController, kTPIsocIOLL, (uintptr_t)this, kIOReturnNoResources, 0, 5 );
            return kIOReturnNoResources;
        }
    }

	dmaCommand = command->GetDMACommand();
	if (!dmaCommand)
	{
		USBLog(1, "%s[%p]::IsocIO(LL) no IODMACommand in the IOUSBCommand", getName(), this);
		USBTrace( kUSBTController, kTPIsocIOLL, (uintptr_t)this, kIOReturnNoResources, 0, 1 );		
		return kIOReturnNoResources;
	}
	
	USBLog(7, "%s[%p]::IsocIO(LL) - putting buffer %p into dmaCommand %p which has getMemoryDescriptor %p", getName(), this, buffer, command->GetDMACommand(), command->GetDMACommand()->getMemoryDescriptor());
	err = dmaCommand->setMemoryDescriptor(buffer);								// this automatically calls prepare()
	if (err)
	{
		USBLog(1, "%s[%p]::IsocIO(LL) - dmaCommand[%p]->setMemoryDescriptor(%p) failed with status (%p)", getName(), this, command->GetDMACommand(), buffer, (void*)err);
		USBTrace( kUSBTController, kTPIsocIOLL, (uintptr_t)this, err, 0, 2 );		
		_freeUSBIsocCommandPool->returnCommand(command);
		return err;
	}
	
	// If the high order bit of the endpoint transfer type is set, then this means it's a request from an Rosetta client
	command->SetRosettaClient(crossEndianRequest);
	
	command->SetIsSyncTransfer(syncTransfer);
	
	// Setup the direction
	if (endpoint->direction == kUSBOut) 
	{
		command->SetSelector(WRITE);
		command->SetDirection(kUSBOut);
	}
	else if (endpoint->direction == kUSBIn) 
	{
		command->SetSelector(READ);
		command->SetDirection(kUSBIn);
	}

	command->SetUseTimeStamp(false);
	command->SetAddress(address);
	command->SetEndpoint(endpoint->number);
	command->SetBuffer(buffer);
	command->SetCompletion( * ((IOUSBIsocCompletion *) completion) );
	command->SetStartFrame(frameStart);
	command->SetNumFrames(numFrames);
	command->SetFrameList( (IOUSBIsocFrame *) frameList);
	command->SetStatus(kIOReturnBadArgument);
	command->SetUpdateFrequency(updateFrequency);
	command->SetLowLatency(true);

	err = _commandGate->runAction(DoIsocTransfer, command);
	
	// If we have a sync request, then we always return the command after the DoIsocTransfer.  If it's an async request, we only return it if 
	// we get an immediate error
	//
	if ( syncTransfer || (kIOReturnSuccess != err) )
	{
		IODMACommand		*dmaCommand = command->GetDMACommand();
		IOMemoryDescriptor	*memDesc = dmaCommand ? (IOMemoryDescriptor	*)dmaCommand->getMemoryDescriptor() : NULL;
		
		if (memDesc)
		{
			USBLog(7, "%s[%p]::IsocIO(LL) - sync xfer or err return - clearing memory descriptor (%p) from dmaCommand (%p)", getName(), this, memDesc, dmaCommand);
			dmaCommand->clearMemoryDescriptor();
		}
		_freeUSBIsocCommandPool->returnCommand(command);
	}

    return err;
}
IOReturn 
IOUSBController::Write(IOMemoryDescriptor *buffer, USBDeviceAddress address, Endpoint *endpoint, IOUSBCompletion *completion, UInt32 noDataTimeout, UInt32 completionTimeout, IOByteCount reqCount)
{
    IOReturn				err = kIOReturnSuccess;
    IOUSBCommand *			command = NULL;
	IODMACommand *			dmaCommand = NULL;
    IOUSBCompletion			nullCompletion;
    int						i;
	bool					isSyncTransfer = false;
	
    USBLog(7, "%s[%p]::Write - reqCount = %qd", getName(), this, (uint64_t)reqCount);
    
    // Validate its a outty pipe and that we have a buffer
    if ((endpoint->direction != kUSBOut) || !buffer || (buffer->getLength() < reqCount))
    {
        USBLog(5, "%s[%p]::Write - direction is not kUSBOut (%d), No Buffer, or buffer length < reqCount (%qd < %qd). Returning kIOReturnBadArgument(0x%x)", getName(), this, endpoint->direction,  (uint64_t)buffer->getLength(), (uint64_t)reqCount, kIOReturnBadArgument);
		return kIOReturnBadArgument;
    }

    if ((endpoint->transferType != kUSBBulk) && (noDataTimeout || completionTimeout))
    {
        USBLog(5, "%s[%p]::Write - Pipe is NOT kUSBBulk (%d) AND specified a timeout (%d, %d).  Returning kIOReturnBadArgument(0x%x)", getName(), this, endpoint->transferType, (uint32_t)noDataTimeout, (uint32_t)completionTimeout, kIOReturnBadArgument);
		return kIOReturnBadArgument;							// timeouts only on bulk pipes
    }
	
    // Validate the command gate
    if (!_commandGate)
    {
        USBLog(5, "%s[%p]::Write - Could not get _commandGate.  Returning kIOReturnInternalError(0x%x)", getName(), this, kIOReturnInternalError);
		return kIOReturnInternalError;
    }

    if (  (uintptr_t) completion->action == (uintptr_t) &IOUSBSyncCompletion )
	{
		isSyncTransfer = true;
		// 7889995 - check to see if we are on the workloop thread before setting up the IOUSBCommand
		if ( _workLoop->onThread() )
		{
            USBError(1,"IOUSBController(%s)[%p]::Write sync request on workloop thread.  Use async!", getName(), this);
            return kIOUSBSyncRequestOnWLThread;
		}
	}
	
	
    // allocate the command
    command = (IOUSBCommand *)_freeUSBCommandPool->getCommand(false);
    
    // If we couldn't get a command, increase the allocation and try again
    //
    if ( command == NULL )
    {
        IncreaseCommandPool();
        
        command = (IOUSBCommand *)_freeUSBCommandPool->getCommand(false);
        if ( command == NULL )
        {
            USBLog(3,"%s[%p]::Write Could not get a IOUSBCommand",getName(),this);
            return kIOReturnNoResources;
        }
    }

	// 7455477: from this point forward, we have the command object, and we need to be careful to put it back if there is an error..
	if (reqCount)
	{
		IOMemoryDescriptor	*memDesc;
		
		dmaCommand = command->GetDMACommand();
		
		if (!dmaCommand)
		{
			USBLog(1, "%s[%p]::Write - no DMA COMMAND", getName(), this);
			USBTrace( kUSBTController, kTPControllerWrite, (uintptr_t)this, kIOReturnNoResources, 0, 1 );
            err = kIOReturnNoResources;
		}
		else
		{
			memDesc = (IOMemoryDescriptor *)dmaCommand->getMemoryDescriptor();
			if (memDesc)
			{
				USBLog(1, "%s[%p]::Write - dmaCommand (%p) already contains memory descriptor (%p) - clearing", getName(), this, dmaCommand, memDesc);
				USBTrace( kUSBTController, kTPControllerWrite, (uintptr_t)this, (uintptr_t)dmaCommand, (uintptr_t)memDesc, 2 );
				dmaCommand->clearMemoryDescriptor();
			}
			USBLog(7, "%s[%p]::Write - setting memory descriptor (%p) into dmaCommand (%p)", getName(), this, buffer, dmaCommand);
			err = dmaCommand->setMemoryDescriptor(buffer);
			if (err)
			{
				USBTrace( kUSBTController, kTPControllerWrite, (uintptr_t)this, err, 0, 4 );
				USBLog(1, "%s[%p]::Write - err(%p) attempting to set the memory descriptor to the dmaCommand", getName(), this, (void*)err);
			}
		}

	}
	
	if (!err)
	{
		command->SetIsSyncTransfer(isSyncTransfer);
		command->SetUseTimeStamp(false);
		command->SetSelector(WRITE);
		command->SetRequest(0);            // Not a device request
		command->SetAddress(address);
		command->SetEndpoint(endpoint->number);
#ifdef SUPPORTS_SS_USB
    	command->SetStreamID(0);
#endif
		command->SetDirection(kUSBOut);
		command->SetType(endpoint->transferType);
		command->SetBuffer(buffer);
		command->SetReqCount(reqCount);
		command->SetClientCompletion(*completion);
		command->SetNoDataTimeout(noDataTimeout); 
		command->SetCompletionTimeout(completionTimeout);
		command->SetMultiTransferTransaction(false);
		command->SetFinalTransferInTransaction(false);
		for (i=0; i < 10; i++)
			command->SetUIMScratch(i, 0);

		nullCompletion.target = (void *) NULL;
		nullCompletion.action = (IOUSBCompletionAction) NULL;
		nullCompletion.parameter = (void *) NULL;
		command->SetDisjointCompletion(nullCompletion);

		err = CheckForDisjointDescriptor(command, endpoint->maxPacketSize);
		if (!err)
		{			
			err = _commandGate->runAction(DoIOTransfer, command);
		}
	}
	
	// 7455477: handle and and all errors which may have occured above
	// If we have a sync request, then we always return the command after the DoIOTransfer.  If it's an async request, we only return it if 
	// we get an immediate error
	//
	if ( isSyncTransfer || (kIOReturnSuccess != err) )
	{
		IOMemoryDescriptor	*memDesc = dmaCommand ? (IOMemoryDescriptor	*)dmaCommand->getMemoryDescriptor() : NULL;

		if (!isSyncTransfer)
		{
			USBLog(2, "%s[%p]::Write - General error (%p) - cleaning up - command(%p) dmaCommand(%p)", getName(), this, (void*)err, command, dmaCommand);
		}

		if (memDesc)
		{
			USBLog(7, "%s[%p]::Write - General error (%p) - clearing memory descriptor (%p) from dmaCommand (%p)", getName(), this, (void*)err, memDesc, dmaCommand);
			dmaCommand->clearMemoryDescriptor();
		}
		nullCompletion = command->GetDisjointCompletion();
		if (nullCompletion.action)
		{
			USBLog(2, "%s[%p]::Write - SYNC xfer or immediate error with Disjoint Completion", getName(), this);
		}
		_freeUSBCommandPool->returnCommand(command);
	}
	
    return err;
}
IOReturn
IOUSBController::CheckForDisjointDescriptor(IOUSBCommand *command, UInt16 maxPacketSize)
{
    IOMemoryDescriptor			*buf = command->GetBuffer();
    IOBufferMemoryDescriptor	*newBuf = NULL;
    IOByteCount					length = command->GetReqCount();
	IODMACommand				*dmaCommand = command->GetDMACommand();
    IOByteCount					segLength = 0;
    IOByteCount					offset = 0;
    IOReturn					err;
	UInt64						offset64;
	IODMACommand::Segment64		segment64;
	UInt32						numSegments;
	
	// USBTrace_Start( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this );
	
    // Zero length buffers are valid, but they are surely not disjoint, so just return success.  
    //
    if ( length == 0 )
        return kIOReturnSuccess;
	
	if (!dmaCommand)
	{
		USBLog(1, "%s[%p]::CheckForDisjointDescriptor - no dmaCommand", getName(), this);
		USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, kIOReturnBadArgument, 0, 1 );
		return kIOReturnBadArgument;
	}
	
	if (dmaCommand->getMemoryDescriptor() != buf)
	{
		USBLog(1, "%s[%p]::CheckForDisjointDescriptor - mismatched memory descriptor (%p) and dmaCommand memory descriptor (%p)", getName(), this, buf, dmaCommand->getMemoryDescriptor());
		USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, kIOReturnBadArgument, (uintptr_t)buf, (uintptr_t)dmaCommand->getMemoryDescriptor(), 2 );
		return kIOReturnBadArgument;
	}
	
    while (length)
    {
		offset64 = offset;
		numSegments = 1;
		
		err = dmaCommand->gen64IOVMSegments(&offset64, &segment64, &numSegments);
        if (err || (numSegments != 1))
        {
            USBLog(1, "%s[%p]::CheckForDisjointDescriptor - err (%p) trying to generate segments at offset (%qd), length (%d), segLength (%d), total length (%d), buf (%p), numSegments (%d)", getName(), this, (void*)err, offset64, (int)length, (int)segLength, (int)command->GetReqCount(), buf, (int)numSegments);
			USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, offset64, length, segLength, 3 );
			USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, segLength, command->GetReqCount(), numSegments, 4 );
            return kIOReturnBadArgument;
        }

		
		// 3036056 since length might be less than the length of the descriptor, we are OK if the physical
		// segment is longer than we need
        if (segment64.fLength >= length)
            return kIOReturnSuccess;		// this is the last segment, so we are OK
		
		// since length is a 32 bit quantity, then we know from the above statement that if we are here we are 32 bit only
		segLength = (IOByteCount)segment64.fLength;

        // so the segment is less than the rest of the length - we need to check against maxPacketSize
        if (segLength % maxPacketSize)
        {
            // this is the error case. I need to copy the descriptor to a new descriptor and remember that I did it
            USBLog(6, "%s[%p]::CheckForDisjointDescriptor - found a disjoint segment of length (%d) MPS (%d)", getName(), this, (int)segLength, maxPacketSize);
			length = command->GetReqCount();		// we will not return to the while loop, so don't worry about changing the value of length
													// allocate a new descriptor which is the same total length as the old one
			newBuf = IOBufferMemoryDescriptor::withOptions((command->GetDirection() == kUSBIn) ? kIODirectionIn : kIODirectionOut, length);
			if (!newBuf)
			{
				USBLog(1, "%s[%p]::CheckForDisjointDescriptor - could not allocate new buffer", getName(), this);
				USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, kIOReturnNoMemory, 0, 5 );
				return kIOReturnNoMemory;
			}
			USBLog(7, "%s[%p]::CheckForDisjointDescriptor, obtained buffer %p of length %d", getName(), this, newBuf, (int)length);
			
			// first close out (and complete) the original dma command descriptor
			USBLog(7, "%s[%p]::CheckForDisjointDescriptor, clearing memDec (%p) from dmaCommand (%p)", getName(), this, dmaCommand->getMemoryDescriptor(), dmaCommand);
			dmaCommand->clearMemoryDescriptor();
			
			// copy the bytes to the buffer if necessary
			if (command->GetDirection() == kUSBOut)
			{
				USBLog(7, "%s[%p]::CheckForDisjointDescriptor, copying %d bytes from desc %p to buffer %p", getName(), this, (int)length, buf, newBuf->getBytesNoCopy());
				if (buf->readBytes(0, newBuf->getBytesNoCopy(), length) != length)
				{
					USBLog(1, "%s[%p]::CheckForDisjointDescriptor - bad copy on a write", getName(), this);
					USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, 0, 0, 6 );
					newBuf->release();
					return kIOReturnNoMemory;
				}
			}
			err = newBuf->prepare();
			if (err)
			{
				USBLog(1, "%s[%p]::CheckForDisjointDescriptor - err 0x%x in prepare", getName(), this, err);
				USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, err, 0, 7 );
				newBuf->release();
				return err;
			}
			err = dmaCommand->setMemoryDescriptor(newBuf);
			if (err)
			{
				USBLog(1, "%s[%p]::CheckForDisjointDescriptor - err 0x%x in setMemoryDescriptor", getName(), this, err);
				USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, err, 0, 8 );
				newBuf->complete();
				newBuf->release();
				return err;
			}
			
			command->SetOrigBuffer(command->GetBuffer());
			command->SetDisjointCompletion(command->GetClientCompletion());
			USBLog(7, "%s[%p]::CheckForDisjointDescriptor - changing buffer from (%p) to (%p) and putting new buffer in dmaCommand (%p)", getName(), this, command->GetBuffer(), newBuf, dmaCommand);
			command->SetBuffer(newBuf);
			
			
			IOUSBCompletion completion;
			completion.target = this;
			completion.action = (IOUSBCompletionAction)DisjointCompletion;
			completion.parameter = command;
			command->SetClientCompletion(completion);
			
			command->SetDblBufLength(length);			// for the IOFree - the other buffer may change size
            return kIOReturnSuccess;
		}
        length -= segLength;		// adjust our master length pointer
		offset += segLength;
	}
	
	USBLog(5, "%s[%p]::CheckForDisjointDescriptor - returning kIOReturnBadArgument(0x%x)", getName(), this, kIOReturnBadArgument);
	// USBTrace_End( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, kIOReturnBadArgument);
	
    return kIOReturnBadArgument;
}