REQUEST_SET_DEVICE_XMIT_PROPERTIES control code

The REQUEST_SET_DEVICE_XMIT_PROPERTIES request sets the maximum speed that is used to transmit requests to a particular device.

The relevant members of the IRB for this request are:


typedef struct _IRB {
  ULONG FunctionNumber;
    .
    .
    .
  union {
    struct {
      ULONG    fulSpeed;
      ULONG    fulPriority;
    } SetDeviceXmitProperties;
    .
    .
    .
  } u;
} IRB;

IRB Input

FunctionNumber

REQUEST_SET_DEVICE_XMIT_PROPERTIES

u.SetDeviceXmitProperties.fulSpeed

Specifies the maximum speed for transactions to the device. The possible speed values are SPEED_FLAGS_xxx, where xxx is the (approximate) transfer rate in megabits per second. Existing hardware supports transfer rates of 100, 200, and 400 Mb/sec.

Transfer RateDescription

SPEED_FLAGS_100

100 Mb/s

SPEED_FLAGS_200

200 Mb/s

SPEED_FLAGS_400

400 Mb/s

 

Reserved.

Note  In Windows 7 and later versions of Windows, you can specify new values higher speed and greater sized payloads. For more information, see New Flags for Speed and Payload Size and IEEE 1394 IOCTL Changes in Device Driver Interface (DDI) Changes in Windows 7.
 

I/O Status Block

The bus driver sets Irp->IoStatus.Status to STATUS_SUCCESS on success, or the appropriate error code on failure.

Operation

By default, the maximum permitted transmission speed is the physical maximum. A driver should use this request to lower the maximum permitted speed.

See Also

IOCTL_IEEE1394_API_REQUEST

Requirements

Header

1394.h (include 1394.h)

 

 

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