libdc1394 2.2.6
fw_cdev_get_cycle_timer Struct Reference

#include <dc1394/juju/firewire-cdev.h>

Detailed Description

struct fw_cdev_get_cycle_timer - read cycle timer register @local_time: system time, in microseconds since the Epoch @cycle_timer: Cycle Time register contents

The FW_CDEV_IOC_GET_CYCLE_TIMER ioctl reads the isochronous cycle timer and also the system clock (CLOCK_REALTIME). This allows to express the receive time of an isochronous packet as a system time.

@cycle_timer consists of 7 bits cycleSeconds, 13 bits cycleCount, and 12 bits cycleOffset, in host byte order. Cf. the Cycle Time register per IEEE 1394 or Isochronous Cycle Timer register per OHCI-1394.

In version 1 and 2 of the ABI, this ioctl returned unreliable (non- monotonic) @cycle_timer values on certain controllers.


The documentation for this struct was generated from the following file: