Re: [Linuxptp-users] phc2sys not synchr. to right time and date

[Keller, J. E <jac...@in...>]

> -----Original Message-----
> From: Vladimir Oltean <ol...@gm...>
> Sent: Thursday, March 24, 2022 11:10 AM
> To: ch...@ch...
> Cc: lin...@li...
> Subject: Re: [Linuxptp-users] phc2sys not synchr. to right time and date
> 
> On Thu, Mar 24, 2022 at 09:14:08AM -0500, Chris Caudle wrote:
> > On Thu, March 24, 2022 5:02 am,
> > lin...@li... wrote:
> > > From: Federico Murciano <Fed...@da...>
> > > Subject: Re: [Linuxptp-users] phc2sys not synchr. to right time and
> > > 	date
> > > Message-ID: <164...@da...>
> >
> > > Thank you for your answer. Yes this is in the slave computer. In the
> > > master computer I only execute the following, which is working for my
> > > other setup (with replicated master and slave devices):
> > >
> > > cat ptp.cfg
> > > [global]
> > > tx_timestamp_timeout 10
> > > step_threshold	 1
> > >
> > > sudo ptp4l -A -i eth0 -m -f ptp.cfg
> >
> > Then what process is expected to set the time for the PHC?  That seems to
> > be a missing step in your configuration.  Perhaps the better question is
> > why does the other setup ever work?
> >
> > --
> > Chris Caudle
> 
> (there might be other reasons why his setup is working, but)
> Some kernel Ethernet drivers have a bad habit of writing the current
> (UTC) system time (derived from the battery-backed RTC) into the PHC
> current (TAI) time at boot. You're off by 37 seconds, but hey, at least
> it's 2022, so the time _must_ be right!
> https://elixir.bootlin.com/linux/latest/source/drivers/ptp/ptp_qoriq.c#L504
> 

If there's a strong recommendation against doing this, should we go fix the in-tree drivers to avoid doing so?

Thanks,
Jake

> 
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