Re: [Linuxptp-users] Interesting (very wrong) PTP output

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

> -----Original Message-----
> From: Richard Cochran [mailto:ric...@gm...]
> Sent: Wednesday, June 06, 2012 9:10 AM
> To: Keller, Jacob E
> Cc: lin...@li...
> Subject: Re: [Linuxptp-users] Interesting (very wrong) PTP output
> 
> On Tue, Jun 05, 2012 at 11:31:24PM +0000, Keller, Jacob E wrote:
> 
> > It seems like somehow the p/i servo code is incorrect because once we
> > hit max adjust it never seems to move away from it.
> 
> The servo clamps the adjustment to the maximum. It looks like it the servo
> output is always outside of the limit. You can inspect s->drift to get a
> better idea what is going on.
> 
> > However that
> > isn't the case when I run ptp4l without that script. I am still trying
> > to determine what the script is doing to the ptp registers on the
> > device (if anything)
> 
> Futzing with the clock or the device registers behind the program's back
> could well cause unexpected results.
> 

The ethtool options script *shouldn't* be doing that, but I am not positive. I'll take a look at the drift value. Also, I ran the test with -l 100 and didn't see any missing timestamp warnings, so all of the timestamp values are at least getting from the driver if not the correct ones.

Thanks

> HTH,
> Richard