Re: [chrony-users] Chrony malfunction under ARM/Buildroot

[Mauro Condarelli <mc5686@xxxxxxxxx>]

Thanks a lot,
comments below.

Il 14/04/2016 23:03, Bill Unruh ha scritto:
> ...snip...

> With no rtc ( which is a hardware problem not a chrony problem) there is no
> > > way the system can know what the time is or how to make sure everything is
> > > always monotonic. You will just have to make sure that the problem never
> > AFAIK chrony (I start it as: "chronyd -r -s") should look for the "driftfile" (present in my system) and set the time&date from it; this does not seem to happen.
>
> That is a driftfile for the rtc. If the rtc is way way out, it has nothing to
> fix-- ie the fix is nonesense. If your rtc is as flaky as you imply, it might
> be better not to use the rtc at all. AFAI remember, if there is not rtc (ie
> the rtcfile directive) chrony will look at a few files, and use the dates from
> them to set the current time. That will be out (depending on how long th
> emachine has been  off) but it will be in the past, so your concern about the
> system always going forward will be satisfied.
If I understand well the "-s" option forces chrony to restart timing from the date of the "driftfile" file (thus providing a monotone, even if wrong, time).
Did misinterpret the manual?
....snip...
> > As said this seems linked to chrony as neither condition happens if chrony is not running.
>
> Yes, but it still might not be chrony. On the other hand the log file you
> showed suggests that it is the rtc that is causing trouble. (Is it HPET? or
> what is the rtc on your system).
My current work hypothesis is something bad happens when chronyd tries to update RTC.
I want to verify this updating RTC with different means (ntpdate).
It might not be conclusive, but will give me some hint (hopefully).
> > I will try substituting nntp/ntpdate in order to see if the problem is in touching time (i.e.: it is in the kernel itself).
>
> The logs suggest that it is a problem with the rtc. You might well be better
> off not using the rtc at all. Is it a separate card?
The RTC is internal to the MCU itself, only the quartz oscillator is external (and that should be OK, because it clocks also other peripherals).
There is a separate power line feeding this part even when the rest of the board is powered off.
A complete reset happens when the Power supply *and* the backup battery are disconnected at the same time.
The strange date&time I get is the value the RTC registers get when completely unprogrammed (i.e.: when the above condition is verified), so that part is "normal".
....snip...
> RTC is internal to MCU, so it might be misprogrammed, but I strongly doubt there is a real hardware issue, also because I see this problem in multiple boards.
> > I will cross-check initializations in both bootloader and .dts
> > If You have specific suggestion please feel free to advise.
>
> I think I have reached the limits of my competence.
:(
Any other taker?

Thanks anyways.
If something comes to mind... ;)

Best Regards
and Thanks again.
Mauro

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