IDE_REQUEST_BLOCK structure (irb.h)
The IDE_REQUEST_BLOCK structure defines an IDE request block.
Syntax
typedef struct _IDE_REQUEST_BLOCK {
USHORT Function;
UCHAR IrbStatus;
UCHAR AtaStatus;
UCHAR AtaError;
UCHAR Channel;
UCHAR TargetId;
UCHAR Lun;
UCHAR CdbLength;
UCHAR SenseInfoBufferLength;
UCHAR SenseInfoBufferType;
UCHAR QueueTag;
ULONG ReservedAsUlong;
ULONG IrbFlags;
ULONG TimeOutValue;
ULONG DataTransferLength;
PVOID IrbExtension;
PVOID DataBuffer;
PVOID SenseInfoBuffer;
PVOID NextIrb;
PVOID Reserved;
union {
IDE_TASK_FILE IdeTaskFile;
UCHAR Cdb[16];
IDE_POWER_INFO PowerChange;
UCHAR AsUChar[16];
};
} IDE_REQUEST_BLOCK, *PIDE_REQUEST_BLOCK;
Members
Function
Specifies the category that the request belongs to. The table below describes the classification of the I/O requests.
| Function | Sub-commands | Description |
| IRB_FUNCTION_ATA_COMMAND |
IRB_FUNCTION_ATA_IDENTIFY
IRB_FUNCTION_ATA_READ IRB_FUNCTION_ATA_WRITE IRB_FUNCTION_ATA_FLUSH IRB_FUNCTION_ATA_SMART |
Indicates that the IRB contains an IdeTaskFile that describes the ATA command. The sub-commands indicate finer grouping of request for faster lookup. |
| IRB_FUNCTION_ATAPI_COMMAND | IRB_FUNCTION_REQUEST_SENSE | Indicates that the IRB contains a CDB that describes the ATAPI command. |
| IRB_FUNCTION_MINIPORT_COMMAND |
IRB_FUNCTION_ADAPTER_FLUSH
IRB_FUNCTION_SHUTDOWN IRB_FUNCTION_POWER_CHANGE IRB_FUNCTION_POWER_REBOOT IRB_FUNCTION_LUN_RESET IRB_FUNCTION_MINIPORT_IOCTL |
Indicates that the IRB is for the miniport. It is the responsibility of the miniport to interpret the command appropriately. |
IrbStatus
The miniport must set this member to indicates the status of the specified operation. The table below describes the various IrbStatus values and their meaning.
| Value | Meaning |
| IRB_STATUS_PENDING | Indicates that the request is in progress. The port driver initializes IrbStatus to this value. A miniport driver should never set the IrbStatus member to this value. |
| IRB_STATUS_SUCCESS | Indicates that the request was completed successfully. |
| IRB_STATUS_DATALENGTH_MISMATCH | Indicates that a data underrun or overrun error occurred. The miniport must update the DataTransferLength field in the IRB to indicate the actual amount of data that was transferred in the case of an underrun. |
| IRB_STATUS_DEVICE_ERROR | Indicates that the device returned an error. The miniport driver must update the AtaStatus and AtaError fields in the Irb to the contents of the device ATA status and error register at the completion of the command. |
| IRB_STATUS_INVALID_REQUEST | Indicates that the miniport does not support the given request. |
| IRB_STATUS_BUS_RESET | Indicates that a bus reset occurred while processing the given request. |
| IRB_STATUS_SELECTION_TIMEOUT | Indicates that the destination device could not be selected. |
| IRB_STATUS_BUSY | Indicates that the device is busy. The port driver retries any request completed with this status. A request completed with busy status is retried only once. It is the responsibility of the miniport driver to pause the request queue using AtaPortDeviceBusy if the device cannot handle request for a certain period of time. |
| IRB_STATUS_AUTOSENSE_VALID | IRB_STATUS_AUTOSENSE_VALID is a bitmask that indicates valid sense data in the SenseInfoBuffer member of the IRB. |
| IRB_STATUS_RETURN_TASKFILE_VALID | IRB_STATUS_RETURN_TASKFILE_VALID is a bitmask that indicates a valid return task file in the SenseInfoBuffer member of the IRB. |
AtaStatus
Indicates the status returned by the device in its status register. The miniport driver should update this field when completing an IRB with IRB_STATUS_DEVICE_ERROR.
AtaError
Indicates the error value returned by the device in its error register. The miniport driver should update this field when completing an IRB with IRB_STATUS_DEVICE_ERROR.
Channel
Specifies the channel number.
TargetId
Specifies the target ID of the device.
Lun
Specifies the logical unit number of the device.
CdbLength
Specifies the length in bytes of the buffer pointed to by Cdb.
SenseInfoBufferLength
Specifies the length in bytes of the buffer pointed to by SenseInfoBuffer.
SenseInfoBufferType
Specifies the type of data structure returned in SenseInfoBuffer. Because ATA commands don't have a need for the request sense command, ATA_PASS_THROUGH commands use SenseInfoBuffer to return task file information. For ATA_PASS_THROUGH commands, as identified in the IrbFlags member, the appropriate return TaskFile size should be reported as either SENSE_INFO_BUFFER_RETURN_TYPE_28BIT_TASKFILE or
SENSE_INFO_BUFFER_RETURN_TYPE_48BIT_TASKFILE.
QueueTag
The queue tag for this IRB. The port driver sets this field to 0.
ReservedAsUlong
Reserved for future use.
IrbFlags
Qualifies the request with certain actions that need to be performed. The table below describes them in detail.
| Flag | Description |
| IRB_FLAGS_DRDY_REQUIRED | Indicates that the miniport driver must wait for the device to set the DRDY bit in the ATA status register before issuing this command. |
| IRB_FLAGS_USE_DMA | Indicates that the request has an associated scatter/gather list and the miniport driver could use DMA to transfer data for this request. |
| IRB_FLAGS_MAP_BUFFERS | Indicates that the DataBuffer field in the IRB is mapped. The miniport can safely access DataBuffer when this flag is set. The miniport driver must not access DataBuffer if the flag is not set. The miniport driver could request the port driver to map the data buffer by setting this flag in the IRB in its IdeHwBuildIo routine. |
| IRB_FLAGS_48BIT | Indicates that the ATA command in the IRB belongs to the 48 bit LBA feature set. The Previous field in the _IDE_TASK_FILE structure is valid when this flag is set. |
| IRB_FLAGS_PIO_MULTIPLE | Indicates that the ATA command is to be transferred using the ATA PIO Multiple method. |
| IRB_FLAGS_RETURN_RESULTS | Indicates that the ATA return task file is to be copied to SenseInfoBuffer. |
| IRB_FLAGS_DATA_IN | Indicates that the data is to be transferred from the device to the host system (a read operation). |
| IRB_FLAGS_DATA_OUT | Indicates that the data is to be transferred to the device from the host system ( a write operation). |
| IRB_FLAGS_DISCARDABLE | Indicates that the command shall be done in a best effort manner. (note: this is not currently employed by ATAport). |
| IRB_FLAGS_HIGH_PRIORITY | Indicates that this IRB is to be processed as soon as possible, before non-high-priority IRBs currently in the ATA miniport. |
TimeOutValue
Indicates the time in seconds after which the request will time out.
DataTransferLength
Contains the length in bytes of the data buffer that contains data to be transferred.
IrbExtension
Pointer to the per-request extension allocated by the port driver.
DataBuffer
Pointer to the buffer where the data resides.
SenseInfoBuffer
Pointer to the buffer which holds the sense data.
NextIrb
Pointer to the next IRB to be processed. The port driver sets this to NULL. The miniport driver can use this field to link IRBs together.
Reserved
Reserved for future use.
IdeTaskFile
Contains a structure of type IDE_TASK_FILE that holds the IDE task file for the indicated controller. This member is defined whenever the result of a bitwise AND between the Function member and IRB_FUNCTION_ATA_COMMAND is nonzero.
Cdb[16]
Contains a command descriptor block (CDB). This member is defined whenever the result of a bitwise AND between the Function member and IRB_FUNCTION_ATAPI_COMMAND is nonzero.
PowerChange
Indicates an enumeration value of type POWER_CHANGE_INFO that defines a power state transition. This member is defined whenever Function is equal to IRB_FUNCTION_POWER_CHANGE.
AsUChar[16]
Provides a means of accessing members IdeTaskFile, PowerChange, and Cdb as unsigned character data.
Remarks
The IDE_REQUEST_BLOCK structure provides a functionality similar to the SCSI_REQUEST_BLOCK but with characteristics more suitable for managing devices on an IDE bus.
Requirements
| Requirement | Value |
|---|---|
| Header | irb.h (include Irb.h) |
See also
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