This was posted on the linuxptp mailing list possibly highlighting an issue
with the igb driver and i219. I thought I would forward it to e1000-devel so
that the right people can get a look at it.
Thanks,
Jake
From: Jan Deinhard [mailto:jan.deinh...@gmail.com]
Sent: Sunday, November 06, 2016 10:57 AM
To: linuxptp-users@lists.sourceforge.net
Subject: Re: [Linuxptp-users] Hardware timestamping does not work
Hi Richard,
2016-11-05 20:26 GMT+01:00 Richard Cochran
<richardcoch...@gmail.com<mailto:richardcoch...@gmail.com>>:
On Sat, Nov 05, 2016 at 04:38:04PM +0100, Jan Deinhard wrote:
> What can I do to find out what the problem is?
I guess that either the imx6 driver is broken by design, or that it is
mis-configured on your board. I would verify that the input clock to
the time stamping unit is the same frequency as the driver expects, or
if the driver detects the frequency, that this is correct.
You will probably have to dig into the data sheet and into the driver
source.
Here is one simple sanity check for the clock. Run
testptp -g; sleep 60; testptp -g
and verify that the difference between the two outputs is about 60
seconds.
The sanity check on the eval board seems ok:
$ ./a.out -f 0; ./a.out -g; sleep 60; ./a.out -g
frequency adjustment okay
clock time: 1478391262.040584932<tel:040584932> or Sun Nov 6 00:14:22 2016
clock time: 1478391322.082633172<tel:082633172> or Sun Nov 6 00:15:22 2016
The difference is 60.04204824<tel:04204824> seconds so I have to check my PC:
$ ./a.out -f 0; ./a.out -g; sleep 60; ./a.out -g
frequency adjustment okay
clock time: 1478445034.316473288 or Sun Nov 6 16:10:34 2016
clock time: 1478445049.319217444 or Sun Nov 6 16:10:49 2016
The difference is 15.002744156 seconds. Ouch!
I guess I have to check the drivers used on my PC or is there anything else I
can do here?
Thanks,
Jan
2016-11-05 20:26 GMT+01:00 Richard Cochran
<richardcoch...@gmail.com<mailto:richardcoch...@gmail.com>>:
On Sat, Nov 05, 2016 at 04:38:04PM +0100, Jan Deinhard wrote:
> I am using a Debian workstation and a i.MX6UL evaluation board running on a
> Linux build with Yocto. According to ethtool -T eth0 both systems support
> PTP hardware timestamping.
...
> ptp4l[26435.632]: master offset 4399753214 s2 freq +32767999 path delay
> -277121915
>
> It is not getting better after some minutes. Master offset is alway
> increasing and freq is always the same value.
The frequency is locked here at maximum offset, and the device is not
converging. This is most likely a driver or HW problem on the imx6.
> Workstation:
>
> $ uname
> -a
>
> Linux polaris 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19)
> x86_64 GNU/Linux
>
> $ lspci
> 00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (2)
> I219-V (rev 31)
If this i219 is working with the igb driver, and the driver shows HW
time stamping enabled, then it should work well. So this isn't the
problem, most likely.
> Eval board:
>
> $ uname -a
> Linux imx6ulevk 4.1.15-2.0.0+gb63f3f5 #1 SMP PREEMPT Wed Nov 2 21:42:19 CET
> 2016 armv7l armv7l armv7l GNU/Linux
I have never tested the ptp driver for the imx6, and I am highly
suspicious of Freescale "quality" drivers.
> What can I do to find out what the problem is?
I guess that either the imx6 driver is broken by design, or that it is
mis-configured on your board. I would verify that the input clock to
the time stamping unit is the same frequency as the driver expects, or
if the driver detects the frequency, that this is correct.
You will probably have to dig into the data sheet and into the driver
source.
Here is one simple sanity check for the clock. Run
testptp -g; sleep 60; testptp -g
and verify that the difference between the two outputs is about 60
seconds.
> Or am I misinterpreting the output?
Looks like a problem on the imx6. You can run a test between the i219
and any other linux PC (even if that PC only has SW time stamping) in
order to exclude a problem with the i219.
> What does the "freq" value mean?
This is the adjustment in parts per billion. Normally the magnitute
of this value should never exceed 100 ppm or so.
HTH,
Richard
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