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.
DESCRIPTION
Returns approximate bus time in nanoseconds for a periodic transaction.
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.