ChangerReinitializeUnit function (mcd.h)

Article
10/21/2021

ChangerReinitializeUnit handles the device-specific aspects of a device-control IRP with the IOCTL code IOCTL_CHANGER_REINITIALIZE_TRANSPORT.

Syntax

NTSTATUS ChangerReinitializeUnit(
  [in] PDEVICE_OBJECT DeviceObject,
  [in] PIRP           Irp
);

Parameters

[in] DeviceObject

Pointer to the device object that represents the changer.

[in] Irp

Pointer to the IRP.

Return value

If the changer supports recalibrating a transport element, ChangerReinitializeUnit returns the STATUS_XXX value returned by the system port driver, or one of the following values:

STATUS_SUCCESS

STATUS_INVALID_ELEMENT_ADDRESS

STATUS_INVALID_PARAMETER

STATUS_INSUFFICIENT_RESOURCES

If the changer does not support recalibrating a transport element, ChangerReinitializeUnit returns STATUS_INVALID_DEVICE_REQUEST.

Remarks

This routine is required.

ChangerReinitializeUnit causes the changer to recalibrate its transport element. Depending on the changer, this may return the transport to a "home" position. The changer class driver typically calls ChangerReinitializeUnit after the changer has been powered on or a calling application has initiated a recovery operation. The CHANGER_DEVICE_REINITIALIZE_CAPABLE flag in Features0 of GET_CHANGER_PARAMETERS indicates whether the changer's transport supports recalibration in those circumstances.

The changer class driver checks the input buffer length in the I/O stack location before calling ChangerReinitializeUnit. Irp->SystemBuffer points to a CHANGER_ELEMENT structure that indicates the element to recalibrate.

ChangerReinitializeUnit builds an SRB with a CDB to position the transport element and sends it to the system port driver.

ChangerReinitializeUnit sets the Information field in the I/O status block to sizeof(CHANGER_ELEMENT) before returning to the changer class driver.

Requirements

Requirement	Value
Target Platform	Desktop
Header	mcd.h (include Mcd.h, Ntddchgr.h)
IRQL	PASSIVE_LEVEL