/*                              SCSIBusAPI.c                            */

/*

 * SCSIBusAPI.c

 * Copyright © 1992-94 Apple Computer Inc. All Rights Reserved.

 */

#include "SCSISimpleSample.h"

/*

 * Check whether the asynchronous SCSI Manager may be called for this bus.

 * This will return a status error if the bus is inaccessable. If successful,

 * it will set useAsynchManager FALSE only if this bus is managed by a

 * third-party SCSI hardware interface that operates by patching the

 * original SCSI Manager traps, or uses some other private interface.

 */

OSErr

SCSIBusAPI(

        DeviceIdent             scsiDevice,

        Boolean                 *useAsynchManager

    )

{

        OSErr                       status;

        SCSIBusInquiryPB            busInquiryPB;

#define PB                          (busInquiryPB)

        if (AsyncSCSIPresent() == FALSE) {

            *useAsynchManager = FALSE;

            status = noErr;

        }

        else {

            CLEAR(PB);

            PB.scsiPBLength = sizeof PB;

            PB.scsiFunctionCode = SCSIBusInquiry;

            PB.scsiDevice = scsiDevice;

            status = SCSIAction((SCSI_PB *) &PB);

            if (status == noErr)

                *useAsynchManager = TRUE;

            else if (scsiDevice.bus == 0) {

                /*

                 * If bus zero is not registered, it must be accessed

                 * via the original API.

                 */

                status = noErr;

                *useAsynchManager = FALSE;

            }

            else {

                /*

                 * This is a problem: this bus cannot be accessed unless it has

                 * been registered. For example, the second bus of a Quadra

                 * 950 cannot be accessed if the SCSI Manager extension is not

                 * isntalled and a third-party asynchronous SCSI Manager card

                 * is installed as bus 2. Return the error to skip this bus.

                 */

            }

        }

        return (status);

#undef PB

}