(originally asked over at askubuntu.com, but is still unresolved: https://askubuntu.com/questions/971349/problem-with-real-time-clock-since-upgrading-to-ubuntu-17-10)
I recently upgraded from Ubuntu 17.04 to Ubuntu 17.10 using the software update process. The update completed without any errors, and Ubuntu 17.10 is now running without any major issues.
However, I was running a script previously that uses rtcwake which has since stopped working. The script automatically hibernates my laptop after a set period of time in sleep mode, and was working perfectly in Ubuntu 17.04.
In the process of troubleshooting, I discovered that the problem was with rtcwake which is complaining about /dev/rtc0 missing.
Here is output from a sample rtcwake command:
peter@haven:~$ rtcwake -m no -s 1300
rtcwake: assuming RTC uses UTC ...
rtcwake: /dev/rtc0: unable to find device: No such file or directory
I verified that in fact, that directory is missing. Since this was working prior to the upgrade, I have to assume that it was there previously, but I don't know for sure.
In researching the error, I found some suggestions to get further information with timedatectl and hwclock, so here are the results from those commands as well.
Output of timedatectl:
peter@haven:~$ timedatectl
Local time: Fri 2017-10-27 19:06:26 EDT
Universal time: Fri 2017-10-27 23:06:26 UTC
RTC time: n/a
Time zone: America/New_York (EDT, -0400)
Network time on: yes
NTP synchronized: yes
RTC in local TZ: no
Output of hwclock --debug:
peter@haven:~$ sudo hwclock --debug
[sudo] password for peter:
hwclock from util-linux 2.30.1
Trying to open: /dev/rtc0
Trying to open: /dev/rtc
Trying to open: /dev/misc/rtc
No usable clock interface found.
hwclock: Cannot access the Hardware Clock via any known method.
UPDATE
When I boot with my old kernel, 4.10.0-37-generic the real-time clock works fine.
I get the following RTC messages in dmesg when I boot the 4.13.0-16-generic kernel:
peter@haven:~$ dmesg | grep -i rtc
[ 0.089393] RTC time: 17:03:55, date: 11/01/17
[ 1.238784] rtc_cmos 00:01: RTC can wake from S4
[ 1.238794] rtc_cmos: probe of 00:01 failed with error -16
[ 1.295459] hctosys: unable to open rtc device (rtc0)
UPDATE #2
Well, I was starting to believe that I had a hardware issue, since discovering I was unable to save changes to my BIOS and could not boot from USB. As it turns out, my laptop was bitten by this bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1734147 causing my BIOS to be locked in a read-only state.
Once I resolved the BIOS issue, and fixed the USB boot problem, I did a live boot of Ubuntu 17.10. The issue with my real time clock still exists under this clean boot scenario, yet when I boot other distros, like Linux Mint 18.3 and the real time clock works fine. I feel this definitely has something to do with the Ubuntu install, perhaps even a kernel bug.
UPDATE #3
More evidence to suggest this is a kernel bug: I live-booted a copy of Antergos Linux, which was using the Arch kernel 4.14.12-1-ARCH and it exhibited the same problem with the real time clock as Ubuntu 17.10. In addition, I confirmed that the Linux Mint version I booted earlier (see Update #2) was on the Ubuntu kernel 4.10.0-38-generic.
So, I suspect that sometime between kernels 4.10 and 4.13 this bug was introduced.
---
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: peter 1832 F.... pulseaudio
/dev/snd/controlC1: peter 1832 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 17.10
HibernationDevice: RESUME=UUID=a602efe1-467d-4ac4-806f-1b931c91cdad
InstallationDate: Installed on 2017-04-05 (292 days ago)
InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.2)
MachineType: LENOVO 20354
Package: linux (not installed)
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-25-generic.efi.signed root=UUID=fa5454aa-9072-475d-b515-acd51a6166cc ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 4.13.0-25.29-generic 4.13.13
RelatedPackageVersions:
linux-restricted-modules-4.13.0-25-generic N/A
linux-backports-modules-4.13.0-25-generic N/A
linux-firmware 1.169.1
Tags: wayland-session artful
Uname: Linux 4.13.0-25-generic x86_64
UpgradeStatus: Upgraded to artful on 2017-10-24 (90 days ago)
UserGroups: adm cdrom dip kismet lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 07/21/2015
dmi.bios.vendor: LENOVO
dmi.bios.version: 9BCN91WW
dmi.board.asset.tag: No Asset Tag
dmi.board.name: Lancer 5A5
dmi.board.vendor: LENOVO
dmi.board.version: 31900058WIN
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo Z50-70
dmi.modalias: dmi:bvnLENOVO:bvr9BCN91WW:bd07/21/2015:svnLENOVO:pn20354:pvrLenovoZ50-70:rvnLENOVO:rnLancer5A5:rvr31900058WIN:cvnLENOVO:ct10:cvrLenovoZ50-70:
dmi.product.family: IDEAPAD
dmi.product.name: 20354
dmi.product.version: Lenovo Z50-70
dmi.sys.vendor: LENOVO
apport information