Re: [Linuxptp-users] using ptp4l on vlan interfaces

[Keller, J. E <jac...@in...>]

> -----Original Message-----
> From: Shawn Bohrer [mailto:sha...@gm...]
> Sent: Tuesday, December 10, 2013 10:48 AM
> To: lin...@li...
> Subject: [Linuxptp-users] using ptp4l on vlan interfaces
> 
> Hello,

Hi :)

> 
> 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?


I am not sure about vlans, but at least for VF drivers, I don't think any currently support PTP.. however I do believe Intel might be able to support hardware timestamps.

To support software timestamps I believe the vlan driver would just have to call the correct software timestamp callback, and advertise that it supports the TX_SOFTWARE timestamping in the ethtool call.

As for the other.. I think you would only be able to access these if you use direct attach of a virtual function.. Then the virtual function driver could setup its own PHC and timestamping as long as the hardware allowed VFs to enable those features.

Regards,
Jake

> 
> Thanks,
> Shawn
> 
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