USB_CALC_BUS_TIME(9)                   Host Controller APIs                  USB_CALC_BUS_TIME(9)



NAME
       usb_calc_bus_time - approximate periodic transaction time in nanoseconds

SYNOPSIS
       long usb_calc_bus_time(int speed, int is_input, int isoc, int bytecount);

ARGUMENTS
       speed
           from dev->speed; USB_SPEED_{LOW,FULL,HIGH}

       is_input
           true iff the transaction sends data to the host

       isoc
           true for isochronous transactions, false for interrupt ones

       bytecount
           how many bytes in the transaction.

RETURN
       Approximate bus time in nanoseconds for a periodic transaction.

NOTE
       See USB 2.0 spec section 5.11.3; only periodic transfers need to be scheduled in software,
       this function is only used for such scheduling.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                      USB_CALC_BUS_TIME(9)