Re: [Linuxptp-users] Status file of achieved time synchronization

[Richard C. <ric...@gm...>]

On Thu, Feb 13, 2014 at 01:01:20PM +0000, Koehrer Mathias (ETAS/ESW5) wrote:

> What kind of information do I get when I call the  'pmc" management client?
> Is it the drift/offset of the PTP clock (Ethernet) or is it the drift/offset of my Linux system clock?

It is the offset with respect to the PTP master. In the case of
software time stamping, this is also the drift of the Linux system
clock WRT the PTP master. Using hardware time stamping, this is the
drift of the PTP hardware clock.

> When I use a PC as PTP master, I have to call phc2sys like
> # phc2sys -c /dev/ptp -s CLOCK_REALTIME -w

I would only do this if you also have "free_running 1" in the
configuration file (and your system time is managed by NTP).

> Or how do I have to call "phc2sys" in the situation when I do not know if the PC will be master or not?

You can simply do the same as in the slave case.

    phc2sys -s /dev/ptp -w

The grand master node will adjust its system time to the free running
PTP Hardware Clock. You will want to set the correct time in the PHC
before doing this!

HTH,
Richard