Re: [Linuxptp-users] question on "-a" option in phc2sys (and boundary clock etc.)

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

On Mon, May 20, 2019 at 12:31:07PM -0400, Sanjay Bhandari wrote:
> > With the *-a* option, the clocks to synchronize are fetched from the
> running *ptp4l* daemon and the direction of synchronization automatically
> follows changes of the PTP port states.
> 
> Is this talking about multiple PTP ports (clocks)?

Yes.

> Is it saying that
> phc2sys will follow the roles decided by the PTP protocol, and set the PHC
> on ports that happen to be masters from a port that is a slave?

You got it!

> All I can
> think is that this applies when the node is a boundary clock. Can someone
> comment?

Um hm.
 
> How does this play with the scenario where the node is the grandmaster?
> What is the direction of time synchronization in that case?

It picks the first interface from the ptp4l command line (or
config. file) as the master clock.

With -r -r you can also serve CLOCK_REALTIME.

HTH,
Richard