[PATCH] rtc: Allow rtc drivers to specify the tv_nsec value for ntp

[Alexandre Belloni]

On 28/11/2017 at 10:20:25 +0000, Russell King - ARM Linux wrote:
> On Mon, Nov 27, 2017 at 08:31:35PM +0100, Alexandre Belloni wrote:
> > On 27/11/2017 at 18:53:52 +0000, Russell King - ARM Linux wrote:
> > > You are, yet again, wrong.
> > > 
> > > I am in a position to make the comment because it was me who identified
> > > the problem, put in the hours to work on, develop and extensively test
> > > Jason's patch.  So, it's partly my time that you seem to be wasting,
> > > and that gives me every right to complain at this point.
> > > 
> > > You, on the other hand, were copied with every single email, and did
> > > nothing to discuss the issue except for the "easy" bits when I posted
> > > a relatively smaller patch - but you ignored the bigger issue.
> > 
> > And this is exactly what you do with other people patches/time when you
> > don't like their changes.
> > You simply ignore the patch series until they go away.
> 
> That is not intentional.
> 

But that is exactly what you are currently reproaching me right now. I
didn't have the time to have a good look a it so I didn't reply it
wasn't intentional either.

You sometimes don't reply to patch series, I sometimes take time to
reply, I don't see how this is different then.

> > I would really expect people merging code in any subsystem to wait for
> > the ack of the maintainer of that subsystem.
> > 
> > I didn't complain about any missing email addresses, I said the RTC ML
> > was not copied but that is didn't matter.
> 
> A mailing list is an email address.
> 

Yes and I said that it didn't matter it was not copied (the patch didn't
make it in patchwork though).

> > What I don't get is that it has been broken for almost 5 years and now
> > you seem to think it has to be fixed urgently.
> 
> Now you're making crap up.  I've not made any comment about this being
> something that needs fixing urgently.  In fact, as I've said several
> times already, I really don't care what you do with the mainline kernel,
> because I have a fix here locally that I intend to use and maintain
> into the future.  For me, the issue is fixed and resolved, and I intend
> to spend no further time developing any fixes for it.
> 

Oh great, that's really the way to go to make progress.

> My comments are about the _two months_ its taken to get to the stage of
> finding out that you don't like the approach.
> 

While I can understand some of the frustration, I don't get why you are
giving up so easily.

> The result of this is, most likely, one of:
> 1. you'll revert the patch (which, incidentally, has no real effect until
>    my other patches get merged) and everyone will either be stuck with a
>    kernel that sets their RTC time wrong when they have NTP installed
> 

Or when using hwclock from util-linux

> 2. you'll remove the systohc code, people won't realise that their kernel
>    no longer sync's the RTC time, and systems that are on the Internet
>    (eg, providing stratum 1 NTP servers) will be unreliable if they are
>    rebooted even more so than they are today.
> 
> > On my side, I want to take the opportunity to think about systohc before
> > adding an ABI that we will maybe regret later.
> 
> Fine, but bear in mind that I don't care anymore, because I have
> perfectly good fixes locally, and I'm not wasting any further time
> in this issue.
> 
> While you think about it, I would encourage anyone who wishing to run
> or running a public NTP server using rtclib to ditch Linux and use
> FreeBSD instead to avoid their NTP server supplying false time, even
> when synchronised to a reference clock.  A reboot of such a server
> will supply false time for a period of a few hours depending on how
> far the time is out (which can be up to a couple of seconds) after
> such an event.  In such a scenario, NTP will not step-correct the
> time but will gradually slew it instead.
> 
> This goes for systems that some ISPs deploy as stratum 1 NTP servers,
> which today tend to be Raspberry Pis.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com