USB_PIPE_INFORMATION_0

The USB_PIPE_INFORMATION_0 structure is used in conjunction with the USB_DEVICE_INFORMATION_0 structure and the QueryDeviceInformation routine to report information about a USB device.

typedef struct _USB_PIPE_INFORMATION_0 {
  USB_ENDPOINT_DESCRIPTOR  EndpointDescriptor;
  UCHAR  ED_Pad[1];
  ULONG  ScheduleOffset;
} USB_PIPE_INFORMATION_0, *PUSB_PIPE_INFORMATION_0;

Members

EndpointDescriptor: Describes the endpoint descriptor. For more information on the endpoint descriptor, see USB_ENDPOINT_DESCRIPTOR.
ED_Pad: Forces double word alignment. This member does not contain meaningful data.
ScheduleOffset: Indicates the schedule offset assigned to the endpoint for this pipe. See the comments section for a discussion of the range of values that this member can take.

Headers

Declared in hubbusif.h. Include hubbusif.h.

Comments

The USB specification labels isochronous and interrupt transfers as "periodic," because certain periods of transmission time are set aside for these types of transfers. The port driver further divides these periods into "schedule offsets" and distributes the available offsets between those endpoints that are doing periodic transfers. The number of offsets that are available depends on the period. The following table lists the offset values that are available for each period.

Period	Available Offsets
1	0
2	0 to 1
4	0 to 3
8	0 to 7
16	0 to 15
32	0 to 31

USB_PIPE_INFORMATION_0

Members

Headers

Comments

See Also