[systemd-devel] Disabling RTC updates on shutdown

[Lennart Poettering]

On Fri, 16.03.12 18:03, Richard Scobie (r.scobie at clear.net.nz) wrote:

> I have a machine with Fedora 16 installed, which is my first
> exposure to systemd.
> 
> I have a requirement to disable the OS updating the CMOS RTC on
> shutdown. This is a not uncommon requirement if
> /sys/class/rtc/rtc0/wakealarm is used, as outlined here:
> 
> http://www.mythtv.org/wiki/ACPI_Wakeup#Disable_HWclock_updates
> 
> After many hours of learning about systemd, downloading the source,
> (while I regularly build from source, I am NOT a programmer), I
> still do not know how to stop this. I used to just comment out a few
> lines in a shutdown script.
> 
> Can some please assist here?

systemd does not update the RTC on shutdown.

We update the RTC in the timedated mechanism when somebody changes the
system time, but we do not delay updating the RTC to shutdown.

If NTP is used the kernel will sync into the RTC every 11 minutes on its
own, however.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.