Re: [Linuxptp-users] PTP through a bridge interface

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

On Tue, Jun 05, 2018 at 02:40:18PM +0000, Rob Cornall wrote:
> I mean #2, a marvell (mv88e6xxx DSA) is used where the cpu port is connected the imx6 ethernet controller.
> 
> Yes It is setup as a linux software bridge via brctl.
> 
> 
> We are aware that having a switch on the master will add some variation of latency, but is it not possible to send ptp packets and receive them through it?

If you leave the switch alone, not as a DSA device, then you can use
eth0 as a PTP port.

Once you make eth0 the CPU port of a DSA device, you cannot use eth0
any more, and you can't use the br0 for PTP either.

So your choice are:

1. Don't use DSA for the Marvell and run ptp4l on eth0.

2. Use the PTP support for the Marvel DSA device (new in Linux kernel v4.17)
   and run ptp4l on the external ports.

HTH,
Richard