Go to main content

man pages section 9: DDI and DKI Properties and Data Structures

Exit Print View

Updated: Thursday, June 13, 2019



usb_ep_descr - USB endpoint descriptor


#include <sys/usb/usba.h> 

Interface Level

Solaris DDI specific (Solaris DDI)


The usb_ep_descr_t endpoint descriptor defines endpoint attributes. An endpoint is a uniquely addressable portion of a USB device that is a source or sink of data.

Please refer to Section 9.6.6 of the USB 2.0 specification. The USB 2.0 specification is available at www.usb.org.

One or more endpoint descriptors are retrieved from a USB device during device enumeration. They can be accessed via usb_get_dev_data(9F).

A endpoint descriptor has the following fields:

uint8_t    bLength                 Size of this descriptor
                                   in bytes.

uint8_t    bDescriptorType         Set to USB_DESCR_TYPE_EP.

uint8_t    bEndpointAddress        Endpoint address.

uint8_t    bmAttributes            Endpoint attrib. (see below.)

uint16_t   wMaxPacketSize          Maximum pkt size.

uint8_t    bInterval               Polling interval for interrupt
                                   and isochro. endpoints.
                                   NAK rate for high-speed control
                                   and bulk endpoints.

Endpoint descriptor bEndpointAddress bitmasks contain address number
and direction fields as follows:
    USB_EP_NUM_MASK        Address bits
    USB_EP_DIR_MASK        Direction bit
    USB_EP_DIR_OUT         OUT towards device
    USB_EP_DIR_IN          IN towards host

Endpoint descriptor transfer type bmAttributes values and mask:
    USB_EP_ATTR_CONTROL    Endpoint supports control transfers
    USB_EP_ATTR_ISOCH      Endpoint supports isochronous xfers
    USB_EP_ATTR_BULK       Endpoint supports bulk transfers
    USB_EP_ATTR_INTR       Endpoint supports interrupt transfers
    USB_EP_ATTR_MASK       bmAttributes transfer-type bit field

Endpoint descriptor synchronization type bmAttributes values and mask
for isochronous endpoints:
    USB_EP_SYNC_NONE       Endpoint supports no synchronization
    USB_EP_SYNC_ASYNC      Endpoint supports asynchronous sync
    USB_EP_SYNC_ADPT       Endpoint supports adaptive sync
    USB_EP_SYNC_SYNC       Endpoint supports synchronous sync
    USB_EP_SYNC_MASK       bmAttributes sync type bit field

Endpoint descriptor feedback type bmAttributes values and mask for
isochronous endpoints:
    USB_EP_USAGE_DATA                 Data endpoint
    USB_EP_USAGE_FEED                 Feedback endpoint
    USB_EP_USAGE_IMPL                 Implicit feedback data endpoint
    USB_EP_USAGE_MASK                 bmAttributes feedback type bit fld

Endpoint descriptor additional-transaction-opportunities-per-microframe
wMaxPacketSize values and mask for high speed isochronous and interrupt
    USB_EP_MAX_PKTSZ_MASK             Mask for packetsize bits
    USB_EP_MAX_XACTS_MASK             Bits for additional transfers per
    USB_EP_MAX_XACTS_SHIFT            Left-shift this number of bits to
                                      get to additional-transfers-per-
                                      microframe bitfield

Endpoint descriptor polling bInterval range values:
    USB_EP_MIN_HIGH_CONTROL_INTRVL    Min NAK rate for highspd ctrl e/p
    USB_EP_MAX_HIGH_CONTROL_INTRVL    Max NAK rate for highspd ctrl e/p

    USB_EP_MIN_HIGH_BULK_INTRVL       Min NAK rate for highspd bulk e/p
    USB_EP_MAX_HIGH_BULK_INTRVL       Max NAK rate for highspd bulk e/p

    USB_EP_MIN_LOW_INTR_INTRVL        Min poll interval, lowspd intr e/p
    USB_EP_MAX_LOW_INTR_INTRVL        Max poll interval, lowspd intr e/p

    USB_EP_MIN_FULL_INTR_INTRVL       Min poll interval, fullspd intr e/p
    USB_EP_MAX_FULL_INTR_INTRVL       Max poll interval, fullspd intr e/p

Note that for the following polling bInterval range values, the interval
is 2**(value-1). See Section 9.6.6 of the USB 2.0 specification.

    USB_EP_MIN_HIGH_INTR_INTRVL       Min poll interval, highspd intr e/p
    USB_EP_MAX_HIGH_INTR_INTRVL       Max poll interval, highspd intr e/p

    USB_EP_MIN_FULL_ISOCH_INTRVL      Min poll interval, fullspd isoc e/p
    USB_EP_MAX_FULL_ISOCH_INTRVL      Max poll interval, fullspd isoc e/p

    USB_EP_MIN_HIGH_ISOCH_INTRVL      Min poll interval, highspd isoc e/p
    USB_EP_MAX_HIGH_ISOCH_INTRVL      Max poll interval, highspd isoc e/p


See attributes(7) for descriptions of the following attributes:

PCI-based systems
Interface Stability

See Also

attributes(7), usb_get_alt_if(9F), usb_get_cfg(9F), usb_get_dev_data(9F), usb_get_string_descr(9F), usb_parse_data(9F), usb_cfg_descr(9S), usb_ctrl_request(9S), usb_dev_descr(9S), usb_dev_qlf_descr(9S), usb_if_descr(9S), usb_other_speed_cfg_descr(9S), usb_string_descr(9S)