usb_get_current_frame_number(9f)

1usb_get_current_frame_numbKeerr(n9eFl)Functions for Dursibv_egrest_current_frame_number(9F)
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NAME

6       usb_get_current_frame_number - Return current logical usb frame number
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SYNOPSIS

9       #include <sys/usb/usba.h>
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13       usb_frame_number_t usb_get_current_frame_number(dev_info_t *dip);
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INTERFACE LEVEL

17       Solaris DDI specific (Solaris DDI)
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PARAMETERS

20       dip    Pointer to the device's dev_info structure.
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DESCRIPTION

24       The usb_get_current_frame_number() function retrieves the current logi‐
25       cal USB frame number.
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28       Isochronous requests can be started on a particular numbered frame.  An
29       offset  number  of  frames (typically between 4 and 10) can be added to
30       the current logical frame number to specify the number of  an  upcoming
31       frame to start an isochronous request.
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34       The  USB  specification  requires  that the frame frequency (the period
35       between start-of-frame packets) is one millisecond.  The Solaris  oper‐
36       ating environment USB implementation uses a running counter of the num‐
37       ber of milliseconds since boot as the current logical frame number.
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RETURN VALUES

40       On success, the  usb_get_current_frame_number()  function  returns  the
41       current  USB  frame number. On failure it returns 0. The function fails
42       if dip is NULL.
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CONTEXT

45       May be called from user, kernel or interrupt context.
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EXAMPLES

48             usb_pipe_handle_t handle;
49             usb_frame_number_t offset = 10;
50             usb_isoc_req_t *isoc_req;
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52             isoc_req = usb_alloc_isoc_req(...);
53               ...
54               ...
55             isoc_req->isoc_frame_no = usb_get_current_frame_number(dip) + offset;
56             isoc_req->isoc_attributes = USB_ATTRS_ISOC_START_FRAME;
57               ...
58               ...
59             if (usb_pipe_isoc_xfer(handle, isoc_req, 0) != USB_SUCCESS) {
60               ...
61             }
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ATTRIBUTES

65       See attributes(5) for descriptions of the following attributes:
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70       ┌─────────────────────────────┬─────────────────────────────┐
71       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
72       ├─────────────────────────────┼─────────────────────────────┤
73       │Architecture                 │PCI-based systems            │
74       ├─────────────────────────────┼─────────────────────────────┤
75       │Interface stability          │Committed                    │
76       ├─────────────────────────────┼─────────────────────────────┤
77       │Availability                 │SUNWusb                      │
78       └─────────────────────────────┴─────────────────────────────┘
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