[systemd-devel] Support machines with multiple RTCs?

[Kay Sievers]

On Tue, Nov 22, 2011 at 23:42, Martin Langhoff
<martin.langhoff at gmail.com> wrote:
> On Tue, Nov 22, 2011 at 3:21 PM, Kay Sievers <kay.sievers at vrfy.org> wrote:
>> Yeah, that's intentional. Udev on other platforms can't know which rtc
>> should be the preferred one.
>
> Well, now you can: if it says hctosys == 1, it means that the kernel
> config told it to pick that one, and that it's sync'd the system time
> to it.

You have rtc1 set in the kernel config for your box?

>> This link is mainly for backwards compat, because in earlier days it
>> was a real kernel device.
>
> Well, the symlink has a very practical use! If you have several RTCs,
> you can use udev to symlink rtc to it, and it gets htclock to DTRT.
>
> On our XO-1.75, the "real" rtc is rtc1.
>
> Next, we got to get src/utils.c to prefer "rtc" if it finds it ;-)

I guess udev should claim /dev/rtc for the rtc device that has hctosys == 1 set?

Kay