Re: [Linuxptp-users] phc2sys required when running ptp4l as master?

[Ledda W. E. <Wil...@it...>]

I'm sorry, I sent my response only to you and not to the list...

> Thank you for your answer. What do you mean by syncronizing the device's clock? What do I syncronize it with?
> In my understanding the ptp0 clock is freerunning. The slaves will try to adjust their clock to the ptp0 clock, whatever time that clock may have.

I missed that you are using ptp4l as master. In this case you are right, ptp0's clock is freerunning and the slaves will be synchronized with it whatever time it is.

William
-----Original Message-----
From: Fabian Schörghofer [mailto:fab...@ya...] 
Sent: 08 March 2016 08:26
To: Ledda William EXT
Cc: lin...@li...
Subject: Re: [Linuxptp-users] phc2sys required when running ptp4l as master?

Thank you for your answer. What do you mean by syncronizing the device's clock? What do I syncronize it with?

In my understanding the ptp0 clock is freerunning. The slaves will try to adjust their clock to the ptp0 clock, whatever time that clock may have.

The goal here is not to have an accurate time (from GPS or whatever source) but rather that master and slave have a precise time. I hope I used the wording here correct.

-----Original Message-----
From: Ledda William EXT 
Sent: 07 March 2016 14:31
To: 'Fabian Schörghofer'
Subject: RE: [Linuxptp-users] phc2sys required when running ptp4l as master?

Since you are using HW time stamping, you need to use phc2sys to synchronize CLOCK_REALTIME. Using HW time stamp ptp4l synchronizes the device's clock, not the system time. 

HTH
William

-----Original Message-----
From: Fabian Schörghofer [mailto:fab...@ya...] 
Sent: 07 March 2016 10:23
To: lin...@li...
Subject: [Linuxptp-users] phc2sys required when running ptp4l as master?

I am using ptp4l with version 1.6-00002-g999c86f.

This is my startline:

/home/test/linuxptp/ptp4l -E -4 -H -i p1p1


The network card is a Intel 82574L with the following time capabilites:

Time stamping parameters for p1p1:
Capabilities:
hardware-transmit     (SOF_TIMESTAMPING_TX_HARDWARE)
software-transmit     (SOF_TIMESTAMPING_TX_SOFTWARE)
hardware-receive      (SOF_TIMESTAMPING_RX_HARDWARE)
software-receive      (SOF_TIMESTAMPING_RX_SOFTWARE)
software-system-clock (SOF_TIMESTAMPING_SOFTWARE)
hardware-raw-clock    (SOF_TIMESTAMPING_RAW_HARDWARE)
PTP Hardware Clock: 0
Hardware Transmit Timestamp Modes:
off                   (HWTSTAMP_TX_OFF)
on                    (HWTSTAMP_TX_ON)
Hardware Receive Filter Modes:
none                  (HWTSTAMP_FILTER_NONE)
all                   (HWTSTAMP_FILTER_ALL)
ptpv1-l4-sync         (HWTSTAMP_FILTER_PTP_V1_L4_SYNC)
ptpv1-l4-delay-req    (HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ)
ptpv2-l4-sync         (HWTSTAMP_FILTER_PTP_V2_L4_SYNC)
ptpv2-l4-delay-req    (HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ)
ptpv2-l2-sync         (HWTSTAMP_FILTER_PTP_V2_L2_SYNC)
ptpv2-l2-delay-req    (HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ)
ptpv2-event           (HWTSTAMP_FILTER_PTP_V2_EVENT)
ptpv2-sync            (HWTSTAMP_FILTER_PTP_V2_SYNC)
ptpv2-delay-req       (HWTSTAMP_FILTER_PTP_V2_DELAY_REQ)


Do I need to use phc2sys on the master too to syncronize the time between the network clock and CLOCK_REALTIME? Or is ptp4l already doing that?

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