Indeed the code in http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/rtc/hctosys.c looks like it runs entirely "self-"triggered (late_initcall), not triggered by an userspace call. This function tries to open the device which simply isn't present (yet) at that time. So maybe this can be moved after the loading of the RTC modules somehow, or the error message quiesced, but I'd like to defer that to a kernel engineer.
** Tags added: bot-stop-nagging xenial -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1410604 Title: ISST-LTE: unable to open rtc device Status in linux package in Ubuntu: Triaged Bug description: == Comment: #0 - Chanh H. Nguyen <[email protected]> - 2015-01-09 17:30:08 == We use DVD to install Ubuntu 15.04 kernel 3.18.0-8-generic version on our PowerVM system. After install, I am seeing this error "/build/buildd/linux-3.18.0/drivers/rtc/hctosys.c: unable to open rtc device" on the dmesg log... root@pole1lp3:~# uname -a Linux pole1lp3 3.18.0-8-generic #9-Ubuntu SMP Mon Jan 5 22:52:15 UTC 2015 ppc64le ppc64le ppc64le GNU/Linux root@pole1lp3:~# dmesg |grep rtc [ 0.556763] /build/buildd/linux-3.18.0/drivers/rtc/hctosys.c: unable to open rtc device (rtc0) [ 3.296241] rtc-generic rtc-generic: rtc core: registered rtc-generic as rtc0 root@pole1lp3:~# == Comment: #2 - David Heller <[email protected]> - 2015-01-13 20:53:50 == It must be an order of operations thing: something is trying to do the hctosys before the driver is loaded. A few seconds later the driver loads and it seems fine after that. root@pole1lp3:~# dmesg | grep rtc [ 0.551202] /build/buildd/linux-3.18.0/drivers/rtc/hctosys.c: unable to open rtc device (rtc0) [ 3.353719] rtc-generic rtc-generic: rtc core: registered rtc-generic as rtc0 root@pole1lp3:~# find /dev -name \*rtc\* /dev/rtc /dev/rtc0 root@pole1lp3:~# hwclock Tue 13 Jan 2015 07:36:15 PM CST -0.779773 seconds root@pole1lp3:~# hwclock --hctosys root@pole1lp3:~# date Tue Jan 13 19:38:05 CST 2015 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1410604/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
