Re: [Linuxptp-users] How to properly use twoStepFlag=0

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

> -----Original Message-----
> From: Keller, Jacob E [mailto:jac...@in...]
> Sent: Monday, January 14, 2019 7:41 AM
> To: Richard Cochran <ric...@gm...>
> Cc: lin...@li...
> Subject: Re: [Linuxptp-users] How to properly use twoStepFlag=0
> 
> > -----Original Message-----
> > From: Richard Cochran [mailto:ric...@gm...]
> > Sent: Sunday, January 13, 2019 12:57 PM
> > To: Keller, Jacob E <jac...@in...>
> > Cc: Timo Korthals <tko...@ci...>; linuxptp-
> > us...@li...
> > Subject: Re: [Linuxptp-users] How to properly use twoStepFlag=0
> >
> > On Fri, Jan 11, 2019 at 11:09:32PM +0000, Keller, Jacob E wrote:
> > > > The two other chips supporting ONESTEP_SYNC are the TI dp83640 and the
> > > > Microchip LAN7430/1.
> > > > However, I only found chip samples but no buyable networkcards having
> > > > these chips.
> > > > Does someone know network cards with these chips or at least other
> > > > network cards with HWTSTAMP_TX_ONESTEP_SYNC support?
> > >
> > > Unfortunately I'm not aware of any that does. :( I thought maybe i210 hardware
> had
> > support, but no one has ever implemented it in the device driver...
> >
> > The i210 does *not* support one-step, but IIRC there is some
> > misleading text that suggests this.
> >
> 
> The data sheet indicates that it does. I haven't tried it myself, so I can't confirm if or
> why the data sheet is wrong.
> 
> > To my knowledge there is no off-the-shelf one-step card on the market.
> >
> > Sorry,
> > Richard
> 
> Yep, that's as much as I know currently as well.
> 
> Thanks,
> Jake
> 

Yea, I read the datasheet section, and it appears that the 1-step insertion doesn't update the UDP checksum, so it would definitely not work for the normal UDP frame PTP, (as checksums will be invalid).

Thanks,
Jake