[systemd-devel] Support machines with multiple RTCs?

[Kay Sievers]

On Tue, Nov 22, 2011 at 21:18, Koen Kooi <koen at dominion.thruhere.net> wrote:
> Op 22 nov. 2011, om 18:28 heeft Kay Sievers het volgende geschreven:
>> On Tue, Nov 22, 2011 at 18:10, Martin Langhoff

>>>  #2 -- is customary to prefer /dev/rtc if present -- so that we can
>>> symlink to the right rtc from udev. src/util.c seems to hardcode rtc0.
>>
>> Udev does that by default today:
>>  SUBSYSTEM=="rtc", DRIVERS=="rtc_cmos", SYMLINK+="rtc"
>
> That looks to be specific to x86 RTCs, in my case when using the RTC of the PMIC
> on omap3/4 I get:
>
>  looking at device '/devices/platform/omap/omap_i2c.1/i2c-1/1-004b/twl_rtc/rtc/rtc0':
>    KERNEL=="rtc0"
>    SUBSYSTEM=="rtc"
>    DRIVER==""

Yeah, that's intentional. Udev on other platforms can't know which rtc
should be the preferred one.

This link is mainly for backwards compat, because in earlier days it
was a real kernel device.

Kay