I'm running into a problem in which an attempt to do a "Mode Select" SCSI command using SPTI is returning an error status of 0x02 ("Check Condition"), and hope someone here might have some tips or suggestions.

The code in question is intended to work with at a custom SCSI device. I wrote the original support for it using ASPI under WinXP, and am converting it to work with SPTI under 64-bit Windows 7.

Here's the problematic code - and what's happening is, sptwb.spt.ScsiStatus is 2, which is a "Check Condition" error. Unfortunately, the device in question doesn't return useful information when you do a "Request Sense" after this problem occurs, so that's no help.

void MSSModeSelect(const ModeSelectRequestPacket& inRequest, StatusResponsePacket& outResponse) 
{
    IPC_LOG("MSSModeSelect(): PathID=%d, TargetID=%d, LUN=%d", inRequest.m_Device.m_PathId,
        inRequest.m_Device.m_TargetId, inRequest.m_Device.m_Lun);
    int adapterIndex = inRequest.m_Device.m_PathId;
    HANDLE adapterHandle = prvOpenScsiAdapter(inRequest.m_Device.m_PathId);
    if (adapterHandle == INVALID_HANDLE_VALUE)
    {
        outResponse.m_Status = eScsiAdapterErr;
        return;
    }

    SCSI_PASS_THROUGH_WITH_BUFFERS sptwb;
    memset(&sptwb, 0, sizeof(sptwb));

#define MODESELECT_BUF_SIZE 32

    sptwb.spt.Length = sizeof(SCSI_PASS_THROUGH);
    sptwb.spt.PathId = inRequest.m_Device.m_PathId;
    sptwb.spt.TargetId = inRequest.m_Device.m_TargetId;
    sptwb.spt.Lun = inRequest.m_Device.m_Lun;
    sptwb.spt.CdbLength = CDB6GENERIC_LENGTH;
    sptwb.spt.SenseInfoLength = 0;
    sptwb.spt.DataIn = SCSI_IOCTL_DATA_IN;
    sptwb.spt.DataTransferLength = MODESELECT_BUF_SIZE;
    sptwb.spt.TimeOutValue = 2;
    sptwb.spt.DataBufferOffset =
       offsetof(SCSI_PASS_THROUGH_WITH_BUFFERS,ucDataBuf);

    sptwb.spt.Cdb[0] = SCSIOP_MODE_SELECT;
    sptwb.spt.Cdb[4] = MODESELECT_BUF_SIZE;

    DWORD length = offsetof(SCSI_PASS_THROUGH_WITH_BUFFERS,ucDataBuf) +
                        sptwb.spt.DataTransferLength;
    memset(sptwb.ucDataBuf, 0, sizeof(sptwb.ucDataBuf));
    sptwb.ucDataBuf[2] = 0x10;
    sptwb.ucDataBuf[16] = (BYTE)0x01;
    ULONG bytesReturned = 0;
    BOOL okay = DeviceIoControl(adapterHandle,
                             IOCTL_SCSI_PASS_THROUGH,
                             &sptwb,
                             sizeof(SCSI_PASS_THROUGH),
                             &sptwb,
                             length,
                             &bytesReturned,
                             FALSE);
    DWORD gle = GetLastError();
    IPC_LOG("  DeviceIoControl() %s", okay ? "worked" : "failed");
    if (okay)
    {
        outResponse.m_Status = (sptwb.spt.ScsiStatus == 0) ? eOk : ePrinterStatusErr;
    }
    else
    {
        outResponse.m_Status = eScsiPermissionsErr;
    }

    CloseHandle(adapterHandle);
}

A few more remarks, for what it's worth:

• This is derived from some old ASPI code that does the "Mode Select" flawlessly.
• This routine opens \\.\SCSI<whatever> at the beginning, via prvOpenScsiAdapter(), and closes the handle at the end. All the other routines for dealing with the device do the same thing, including the routine to do "Reserve Unit". Is this a good idea under SPTI, or should the call to "Reserve Unit" leave the handle open, so this routine and others in the sequence can use the same handle?
• This uses the IOCTL_SCSI_PASS_THROUGH. Should "Mode Select" use IOCTL_SCSI_PASS_THROUGH_DIRECT instead?

Thanks in advance - any help will be greatly appreciated.