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Inside Macintosh: Devices /

Chapter 4 - SCSI Manager 4.3 / SCSI Manager 4.3 Reference

SCSI Manager 4.3 Functions / Client Functions

SCSIResetBus

You use the SCSIResetBus function to reset a SCSI bus.

OSErr SCSIAction(SCSI_PB *scsiPB);

scsiPB

A pointer to a SCSI Manager parameter block.

-->	scsiPBLength	UInt16	The size of the parameter block.
-->	scsiFunctionCode	UInt8	The SCSIResetBus function selector code (0x11).
<--	scsiResult	OSErr	The returned result code.
-->	scsiDevice	DeviceIdent	The device identification record. Only the bus number is required.
-->	scsiCompletion	CallbackProc	A pointer to a completion routine. If set to nil, the function is executed synchronously.
-->	scsiDriverStorage	UInt8 *	Optional pointer to the device driver's private storage.

DESCRIPTION

The SCSIResetBus function directs the HBA to assert the SCSI bus reset signal, causing all devices on the bus to clear pending I/O and forcing the bus into the bus free phase. In addition, the SIM calls the completion routines for all requests that were already delivered to devices. The appropriate LUN queue is frozen for each of the requests that were reset, unless the scsiSIMQNoFreeze flag is set.

SPECIAL CONSIDERATIONS

The SCSIResetBus function interrupts SCSI communications and can cause data loss. You should use this function only to restore operation in the event that a device refuses to release the bus. You can use the SCSIResetDevice function to reset a single device when the SCSI bus is operational and the device is still responding to selection.

RESULT CODES

noErr	0	No error
scsiBusInvalid	-7869	The bus ID is invalid
scsiRequestInvalid	-7870	The parameter block request is invalid
scsiPBLengthError	-7872	The parameter block is too small for this SIM
scsiQLinkInvalid	-7881	The qLink field was not 0