[Linuxptp-users] using ptp4l on vlan interfaces

[Shawn B. <sha...@gm...>]

Hello,

I'm currently a PTPd user but I'm interested in ptp4l especially if I
can take advantage of hardware timestamp support.  First step was to
see if I could simply run ptp4l utilizing software timestamps and I
ran into a bit of a snag.  We currently run ptpd on a vlan but
attempting to run ptp4l on a vlan interface results in the following:

# ptp4l -S -i vlan807 -s -l7 -m
interface 'vlan807' does not support requested timestamping mode.

I took a look at the code and can see this is because vlan interfaces
do not report that they support SOF_TIMESTAMPING_TX_SOFTWARE.  The
underlying device interface eth4 however does claim to support
SOF_TIMESTAMPING_TX_SOFTWARE.

So I guess I have a couple of questions here regarding ptp4l and
vlans.  The first big question is of course is it possible to run
ptp4l on a vlan?  Assuming the actual device and driver support
hardware timestamps (or software TX) and provide a PHC is it possible
to access those through a vlan?

Thanks,
Shawn