[systemd-devel] Cannot find a way to get time read from RTC during boot

[Dave Howorth]

On Thu, 12 Mar 2020 17:35:16 -0400
"Kevin P. Fleming" <kevin at km6g.us> wrote:
> Thanks, I agree. I could some up with something which ran timedatectl
> to set the system time from the RTC, but the hwclock tool is already
> there for that purpose.
> 
> I'll need to investigate why this script exits without making any
> changes when systemd is running; either the authors expected some part
> of systemd to read the RTC, or they expect some other service/tool to
> do it.
> 
> On Thu, Mar 12, 2020 at 2:02 PM Mike Gilbert <floppym at gentoo.org>
> wrote:
> >
> > On Thu, Mar 12, 2020 at 7:13 AM Kevin P. Fleming <kevin at km6g.us>
> > wrote:  
> > > Prior to systemd, with the 'hwclock' package installed, a udev
> > > rule would trigger reading of the RTC and setting the system
> > > clock when /dev/rtc0 appeared. With systemd running, the script
> > > run by that udev rule is suppressed, it doesn't do anything.
> > >
> > > With a system using solely systemd-provided services, what's the
> > > proper mechanism to get the time read from an RTC whose driver is
> > > loaded by systemd-modules-load.service?  
> >
> > Your use case is likely not covered by "systemd-provided" services.
> >
> > I think your best bet would be to "un-supress" that hwclock udev
> > rule.  

I'm not sure but you might be interested to read
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=855203