[Linuxptp-users] Intermittent send delay request failure (tx_timestamp_timeout) w/dp83640

[Dan G. <gee...@gm...>]

I would like to start with my thanks for the support of the Linux PTP
Project.  The tools are a great success, and keep getting better!

I'm developing a custom SBC that works perfectly approximately 90% of the
time.  However, when the SBC starts or restarts there are cases immediately
after initialization where ptp4l goes into a repeating cycle of 1) syncing
to a PTP Grand Master, 2) timing out on the port_delay_request, and 3)
resetting the failed port.

My SBC is based on a MPC8360E (NXP PowerQUICC® II Pro Processor with
ucc_geth MACs) connected to DP83640 PHYTERs.  I'm building the entire
distro using yoctoproject's honister release, and Linux 5.10.73 with
the CONFIG PREEMPT RT Patch. I recently upgraded to linuxptp 3.1.1.  Ptp4l
is configured for Hardware timestamps and twoStepFlag = 0.  It appears that
the device drivers support PTP since the time sync works extremely well
most of the time.

I'm in the process of trying to isolate the cause of the failure, but when
everything works most of the time, this can be a big challenge.  I
understand the statement that this is "likely a driver bug", and would like
to know if anyone can point me in the right direction.

Which driver should I focus on?

Is this more likely in the dp83640 PHY layer, or the ucc_geth MAC layer?

And, can you please offer any suggestions on how I might isolate the cause
of the repeating poll timeout? (I might need to provide the fix to the
maintainer)


Thank you in advance for your help!
Dan