Re: Timezone problems on -current

On 2021-May-3, at 08:34, bob prohaska <fbsd at www.zefox.net> wrote:

> It seems that the timezone gets screwed up each time the OS is
> upgraded on a Pi4  via sources on -current. ntpdate is working, but the
> machine reports a local time of 
> bob@nemesis:~ % date
> Mon May  3 15:27:04 PDT 2021
> while a Pi2 reports
> fbsd@www:~ % date
> Mon May  3 08:28:35 PDT 2021
> 
> The timezone is PDT in both cases, but the time shown looks like 
> UTC for the Pi4 but PDT for the Pi2.

Note: I assume that neither RPi* has a RTC, not that
it makes much of a difference here.

I expect that one RPi* has a file:

# ls -Tld /etc/wall_cmos_clock 
-r--r--r--  1 root  wheel  0 Aug  8 01:49:01 2017 /etc/wall_cmos_clock

and the other does not.

QUOTE ( from https://www.freebsd.org/cgi/man.cgi?adjkerntz(8) )
. . .
     . . . If the file /etc/wall_cmos_clock  exists, it means
     that the CMOS clock keeps local time (MS-DOS and MS-Windows compatible
     mode).  If	that file does not exist, it means that	the CMOS clock keeps
     UTC time.
. . .
     /etc/wall_cmos_clock  Empty file.	Its presence indicates that the	ma-
			   chine's CMOS	clock is set to	local time, while its
			   absence indicates a UTC CMOS	clock.
END QUOTE

However, it has an effect on time handling even when
no RTC (no CMOS clock) is present.

If you want times to look right on ms-dos and Windows for the
msdos file system involved, you then want to boot and
synchronize time with /etc/wall_cmos_clock present.

Otherwise you likely do not want /etc/wall_cmos_clock present
for such activities.

If you want times to closely agree, all RPi*'s should have the
same /etc/wall_cmos_clock status, which ever way you go.

There can be an issue of time going backwards, depending on
the delete vs. add action for /etc/wall_cmos_clock .

> I've noticed this before and cured it for a while by running tzsetup.
> The problem seems to return each time the OS is upgraded, though I
> have not kept careful track of what's going on. Anybody else noticed
> this?



===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)

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