[systemd-devel] Disabling RTC updates on shutdown

[Lennart Poettering]

On Sat, 17.03.12 08:11, Richard Scobie (r.scobie at clear.net.nz) wrote:

Heya,

> >We update the RTC in the timedated mechanism when somebody changes the
> >system time, but we do not delay updating the RTC to shutdown.
> 
> This may explain the intermittent nature of the problem I am seeing.
> The system is a PVR based on the software vdr, which is only waking
> up at wakealarm time about 70% of the time.
> 
> It has a feature which I have enabled, to synchronise system time to
> time data contained in a prefered DVB-S transponder stream. This
> synchronisation does not occur every startup - maybe only after a
> certain window is exceeded.
> 
> Would this trigger the timedated RTC update and if so, how would I
> prevent it?

Nope, this would not explain that really. The only consumer for
timedated I know is GNOME3. I am pretty sure vdr is not a consumer of
this interface (but dunno, i didn't actually check).

My guess is that vdr might sync both the system clock and the RTC at the
same time (which I'd argue is the right thing to do).

If your RTC loses the wakeup time when the RTC is adjusted this is
probably something the kernel should work around (by reading the wakeup
time before and rewriting it after changing the RTC).

Lennart

-- 
Lennart Poettering - Red Hat, Inc.