On Wed, Nov 06, 2019 at 11:11:27AM +0000, jawad ahmed saleemi wrote:
> In our setup, when the grandmaster reboots, the ptp slave gets out
> of sync and is unable to resync again. The ptp slave shows a huge
> offset once the grandmaster comes back up and it remains like
> this. When I set the step_threshold parameter to 0.00002, the offset
> reduces but the port state stays in UNCALIBRATED state and is unable
> to switch to RS_SLAVE state. 

The step_threshold is not applied when UNCALIBRATED.  It only applies
when the slave is in the SLAVE state.

> On further increasing the step_threshold parameter to 0.02, the ptp
> slave is able to resync with the master and switch to RS_SLAVE state
> easily. I am confused about what is going on here. Why didn't
> 0.00002 worked but 0.02 did.

We need to understand why the slave gets stuck in UNCALIBRATED.
Please post a log.

> In the manpage it says,
> 
> The maximum offset the servo will correct by changing the clock
> frequency instead of stepping the clock. This is only applied on the
> first update.
> I would like to know what does "first update" mean in this context.

The first update is applied during the transition from the
UNCALIBRATED to the SLAVE state.

Thanks,
Richard


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