Manual Pages for UNIX Operating System command usage for man usb_get_current_frame_number

Kernel Functions for Drivers     usb_get_current_frame_number(9F)



NAME
     usb_get_current_frame_number - Return  current  logical  usb
     frame number

SYNOPSIS
     #include 

     usb_frame_number_t usb_get_current_frame_number(dev_info_t *dip);


INTERFACE LEVEL
     Solaris DDI specific (Solaris DDI)

PARAMETERS
     dip    Pointer to the device's dev_info structure.


DESCRIPTION
     The usb_get_current_frame_number()  function  retrieves  the
     current logical USB frame number.


     Isochronous requests can be started on a particular numbered
     frame.  An  offset number of frames (typically between 4 and
     10) can be added to the  current  logical  frame  number  to
     specify the number of an upcoming frame to start an isochro-
     nous request.


     The USB specification requires that the frame frequency (the
     period  between  start-of-frame packets) is one millisecond.
     The Solaris operating environment USB implementation uses  a
     running  counter of the number of milliseconds since boot as
     the current logical frame number.

RETURN VALUES
     On  success,  the  usb_get_current_frame_number()   function
     returns  the current USB frame number. On failure it returns
     0. The function fails if dip is NULL.

CONTEXT
     May be called from user, kernel or interrupt context.

EXAMPLES
           usb_pipe_handle_t handle;
           usb_frame_number_t offset = 10;
           usb_isoc_req_t *isoc_req;

           isoc_req = usb_alloc_isoc_req(...);
             ...
             ...
           isoc_req->isoc_frame_no = usb_get_current_frame_number(dip) + offset;



SunOS 5.11          Last change: 25 July 2004                   1






Kernel Functions for Drivers     usb_get_current_frame_number(9F)



           isoc_req->isoc_attributes = USB_ATTRS_ISOC_START_FRAME;
             ...
             ...
           if (usb_pipe_isoc_xfer(handle, isoc_req, 0) != USB_SUCCESS) {
             ...
           }


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Architecture                | PCI-based systems           |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | Availability                | driver/usb                  |
    |_____________________________|_____________________________|


SEE ALSO
     attributes(5),                       usb_alloc_isoc_req(9F),
     usb_get_max_pkts_per_isoc_request(9F),
     usb_pipe_isoc_xfer(9F),
     usb_pipe_get_max_bulk_transfer_size(9F),
     usb_isoc_request(9S)
























SunOS 5.11          Last change: 25 July 2004                   2