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I am using ptp4l on linux machine. Currently, in the pcap trace I can see that the flag for PTP_Timescale is set to False. Is there anyway, that I can configure the PTP_Timescale parameter and set it to True?

Pratul Jn
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1 Answers1

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The pmc tool may be the answer you are looking for (I think the pmc tool is included in the linuxptp package).

First Step:

Let's try and read your current configuration using the pmc tool:

sudo pmc -u -b 0 'GET GRANDMASTER_SETTINGS_NP'

You should get a response in this structure:

sending: GET GRANDMASTER_SETTINGS_NP                                           
        020e06.fffe.814208-0 seq 0 RESPONSE MANAGEMENT GRANDMASTER_SETTINGS_NP 
                clockClass              255                                    
                clockAccuracy           0x21                                   
                offsetScaledLogVariance 0x436a                                 
                currentUtcOffset        37                                     
                leap61                  0                                      
                leap59                  0                                      
                currentUtcOffsetValid   1                                      
                ptpTimescale            0                                      
                timeTraceable           0                                      
                frequencyTraceable      0                                      
                timeSource              0xa0

Second Step:

Let's modify the timeTraceable flag to 1 using a pmc command (please note that I'm not changing the other flags - I'm writing the same values I've just read, except the timeTraceable that we want to change):

sudo pmc -u -b 0 "SET GRANDMASTER_SETTINGS_NP clockClass 255 \
            clockAccuracy 0x21 offsetScaledLogVariance 0x436a \
            currentUtcOffset 37 leap61 0 leap59 0 currentUtcOffsetValid 1 \
            ptpTimescale 1 timeTraceable 0 frequencyTraceable 0 \
            timeSource 0xa0"

I hope this will do the job. If it doesn't help, try have a look at this links for more details:
pmc man page
pmc example

J.M.
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  • I already tried to set the timesclace using pmc. But, in the trace I see that the ptp_timescale is still 0 (though I updated the Grandmaster settings using pmc). – Pratul Jn Feb 15 '21 at 12:23
  • Did you try the exact command I've posted here ? I tried it on one of my slaves/clients and the flag did changed his value. (note that when I tried the command with "pmc -t...." it didn't work, so I removed the "-t". don't know why it didn't work that way) – J.M. Feb 15 '21 at 12:30
  • When you type again: sudo pmc -u -b 0 'GET GRANDMASTER_SETTINGS_NP' , the "timeTraceable" is still set to '0' ? – J.M. Feb 15 '21 at 12:32
  • When try 'GET GRANDMASTER_SETTINGS_NP', the ptp_timescale is set to 1. But, in the wireshark trace i see that the ptp_timescale is still 0. – Pratul Jn Feb 16 '21 at 15:19