Re: [Linuxptp-users] sanity_freq_limit

[Daniel Le <dan...@ex...>]

Does ptp4l step only once (assuming the default first_step_threshold of 20 microseconds is met) no matter how master offsets vary afterward?

Daniel

-----Original Message-----
From: Daniel Le 
Sent: Friday, June 19, 2015 4:10 PM
To: 'Richard Cochran'
Cc: Lin...@li...
Subject: Re: [Linuxptp-users] sanity_freq_limit

"...or that the change in time is not reflected in the subsequent time stamps". This is a good pointer for debugging. The system clock may have been stepped, but the FPGA hardware clock is not stepped and continues to provide the timestamps from its un-stepped clock.

Much appreciate it.
Daniel

-----Original Message-----
From: Richard Cochran [mailto:ric...@gm...]
Sent: Friday, June 19, 2015 3:59 PM
To: Daniel Le
Cc: Lin...@li...
Subject: Re: [Linuxptp-users] sanity_freq_limit

On Fri, Jun 19, 2015 at 07:43:01PM +0000, Daniel Le wrote:
> 
> PHC is not used in my system. I have a proprietary NIC FPGA-based MAC 
> driver which has its own hardware clock, and in this scheme, 
> synchronizes to the Linux system clock that in turn is synchronized to 
> PTP Grandmaster via software timestamping mechanism. The timestamps of 
> PTP packets are provided by the FPGA MAC driver may cause problem. It 
> seems that the system clock fails to be stepped.

Okay, so you have a special custom setup.  I cannot really guess what is wrong, but it does appear that whatever clock you are using is failing to jump, or that the change in time is not reflected in the subsequent time stamps.

Thanks,
Richard

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