Bug#785445: Bug#785419: linux-image-4.0.0-1-armmp: with 2 RTC devices -- need way to chose which one sets system clock on boot

[Rick Thomas]

On May 16, 2015, at 3:13 AM, Ian Campbell <ijc at debian.org> wrote:

> On Fri, 2015-05-15 at 17:55 -0700, Rick Thomas wrote:
> [...]
>> There does not seem to be any way to over-ride this.  There's code in /etc/default/hwclock
>> that would do part of the work in a sysvinit setup, but it seems to be ignored under systemd.
> [...]
>> Presumably, there is systemd magic that could do the same thing as was available under
>> sysvinit.  Is there anybody out there with enough systemd foo to tell me how to do that?
> 
> I think that if systemd is not supporting /etc/default/hwclock and the
> replacement mechanism is not apparent after some searching of the docs
> etc then this should be considered a systemd bug (either in the docs if
> not an actual code bug or missing feature).
> 
> Perhaps someone on the pkg-systemd-maintainers at alioth list will be
> better able to advise on if/how systemd solves this problem?
> 
> Ian.

Thanks, Ian, for the prompt response.  I’ve submitted a separate bug to systemd asking for a fix.  However, it may not be possible to do this with systemd…  Looking at the dmesg output, it looks like the decision to use /dev/rtc0 is being made at the kernel level, before systemd even gets started.  If that’s correct, I’m not sure if even sysvinit with /etc/default/hwclock could have done the right thing in my case.

Do you happen to know why the patch I came across never made it into the kernel?

Thanks, again!
Rick