Comment 1 for bug 252924

Hi Jimmy,

Thanks for the report. I've done some additional investigation. It appears that CONFIG_RTC being enabled is dependent on CONFIG_RTC_LIB being disabled. For the Intrepid kernel however, CONFIG_RTC_LIB is in fact enabled:

ogasawara@yoji:~/ubuntu-intrepid/debian/config$ grep -rn "CONFIG_RTC_LIB" *
amd64/config:2251:CONFIG_RTC_LIB=y
i386/config:2397:CONFIG_RTC_LIB=y

I also noticed an interesting comment in the Kconfig regarding CONFIG_RTC:

ogasawara@yoji:~/ubuntu-intrepid/drivers/char$ grep -A7 -B7 "config RTC" Kconfig

#
# These legacy RTC drivers just cause too many conflicts with the generic
# RTC framework ... let's not even try to coexist any more.
#
if RTC_LIB=n

config RTC
 tristate "Enhanced Real Time Clock Support (legacy PC RTC driver)"
 depends on !PPC && !PARISC && !IA64 && !M68K && !SPARC && !FRV \
   && !ARM && !SUPERH && !S390 && !AVR32
 ---help---
   If you say Y here and create a character special file /dev/rtc with
   major number 10 and minor number 135 using mknod ("man mknod"), you
   will get access to the real time clock (or hardware clock) built

As you can see, "These legacy RTC drivers just cause too many conflicts with the generic RTC framework ... let's not even try to coexist any more." I'm guessing that the kernel team won't likely disable CONFIG_RTC_LIB in favor of using legacy drivers, but that's just my thought. I did however also notice something else interesting:

ogasawara@yoji:~/ubuntu-intrepid/debian/config$ grep -rn "CONFIG_RTC_INTF_DEV=" *
amd64/config:2247:CONFIG_RTC_INTF_DEV=y
i386/config:2393:CONFIG_RTC_INTF_DEV=y

ogasawara@yoji:~/ubuntu-intrepid/drivers/rtc$ grep -m1 -A12 "config RTC_INTF_DEV" Kconfig
config RTC_INTF_DEV
 boolean "/dev/rtcN (character devices)"
 default RTC_CLASS
 help
   Say yes here if you want to use your RTCs using the /dev
   interfaces, which "udev" sets up as /dev/rtc0 through
   /dev/rtcN. You may want to set up a symbolic link so one
   of these can be accessed as /dev/rtc, which is a name
   expected by "hwclock" and some other programs.

   This driver can also be built as a module. If so, the module
   will be called rtc-dev.

I'm curious if you create /dev/rtc as a symlink to /dev/rtc0 if this will resolve the warning you are seeing? Let us know. Thanks.