SCSI_POWER_REQUEST_BLOCK structure (srb.h)

Article
09/01/2022

The SCSI_POWER_REQUEST_BLOCK structure is a special version of a SCSI_REQUEST_BLOCK that is used for power management requests.

Note The SCSI port driver and SCSI miniport driver models may be altered or unavailable in the future. Instead, we recommend using the Storport driver and Storport miniport driver models.

Syntax

typedef struct _SCSI_POWER_REQUEST_BLOCK {
  USHORT                     Length;
  UCHAR                      Function;
  UCHAR                      SrbStatus;
  UCHAR                      SrbPowerFlags;
  UCHAR                      PathId;
  UCHAR                      TargetId;
  UCHAR                      Lun;
  STOR_DEVICE_POWER_STATE    DevicePowerState;
  ULONG                      SrbFlags;
  ULONG                      DataTransferLength;
  ULONG                      TimeOutValue;
  PVOID                      DataBuffer;
  PVOID                      SenseInfoBuffer;
  struct _SCSI_REQUEST_BLOCK *NextSrb;
  PVOID                      OriginalRequest;
  PVOID                      SrbExtension;
  STOR_POWER_ACTION          PowerAction;
  ULONG                      Reserved;
  UCHAR                      Reserved5[16];
} SCSI_POWER_REQUEST_BLOCK, *PSCSI_POWER_REQUEST_BLOCK;

Members

Length

The size, in bytes, of the SCSI_POWER_REQUEST_BLOCK structure.

Function

The operation to perform. For the SCSI_POWER_REQUEST_BLOCK structure, this member is always set to SRB_FUNCTION_POWER.

SrbStatus

The status of the completed request. This member should be set by the miniport driver before it notifies the Storport driver that the request has completed. A miniport driver notifies the Storport driver that the request has completed by calling the StorPortNotification function with the RequestComplete notification type.

See SCSI_REQUEST_BLOCK in the WDK documentation for a list of possible values for this member.

SrbPowerFlags

The power management flags. Currently, the only flag allowed is SRB_POWER_FLAGS_ADAPTER_REQUEST, which indicates that the power management request is for the adapter. If this flag is set, the miniport driver should ignore the values in the PathId, TargetId, and Lun.

PathId

The SCSI port or bus identifier for the request. This value is zero based.

TargetId

The target controller or device identifier on the bus.

Lun

The logical unit number (LUN) of the device.

DevicePowerState

An enumerator value of type STOR_DEVICE_POWER_STATE that specifies the requested power state of the device.

SrbFlags

Miniport driver should ignore this member.

DataTransferLength

Miniport driver should ignore this member.

TimeOutValue

The interval, in seconds, that the request can execute before the Storport driver determines that the request has timed out.

DataBuffer

Miniport driver should ignore this member.

SenseInfoBuffer

Miniport driver should ignore this member.

NextSrb

Miniport driver should ignore this member.

OriginalRequest

Miniport driver should ignore this member.

SrbExtension

A pointer to the SRB extension. A miniport driver must not use this member if it set SrbExtensionSize to zero in the HW_INITIALIZATION_DATA structure. The Storport driver does not initialize the memory that this member points to. The HBA can directly access the data that the miniport driver writes into the SRB extension. A miniport driver can obtain the physical address of the SRB extension by calling the StorPortGetPhysicalAddress routine.

PowerAction

An enumerator value of type STOR_POWER_ACTION that specifies the type of system shutdown that is about to occur. This value is meaningful only if the device is moving into the D1, D2, or D3 power state as indicated by the DevicePowerState member.

Reserved

Reserved for system use.

Reserved5[16]

Reserved for system use.

Remarks

The Storport driver calls HwStorBuildIo to pass SRBs to the miniport driver. HwStorBuildIo should check the Function member of the SRB to determine the type of the SRB. If the Function member is set to SRB_FUNCTION_POWER, the SRB is a structure of type SCSI_POWER_REQUEST_BLOCK.

The Storport driver sends SCSI_POWER_REQUEST_BLOCK requests to a miniport driver to notify the miniport driver of Windows power events that affect storage devices that are connected to the adapter. In the case of a power up event, this request gives the miniport driver an opportunity to initialize itself. In the case of a hibernation or shutdown event, this request gives the miniport driver an opportunity to complete I/O requests and prepare for a power down. The miniport driver can use the value in the PowerAction member of the SCSI_POWER_REQUEST_BLOCK to determine what actions are required. After the miniport driver completes the SCSI_POWER_REQUEST_BLOCK request, the Storport driver calls HwScsiAdapterControl with a control request of ScsiStopAdapter to power down the adapter. The miniport driver reinitialize while processing the SRB_FUNCTION_POWER request, or it can wait and reinitialize when the Storport driver calls HwStorAdapterControl to perform a an ScsiRestartAdapter control request.

When transitioning from the D0 power state to a lower-powered state (D1, D2, or D3) the Storport driver sends a SCSI_POWER_REQUEST_BLOCK request to the miniport driver before the underlying bus driver powers down the adapter.

The following conditions must exist before the Storport driver will send a SCSI_POWER_REQUEST_BLOCK request to the miniport driver:

The adapter is not stopped.
The I/O queue for the adapter is paused.
The adapter hardware is powered up.
The miniport can access the adapter's hardware resources.

Requirements

Requirement	Value
Header	srb.h (include Storport.h, Minitape.h, Srb.h)

See also

SCSI_REQUEST_BLOCK

StorPortNotification