[LE11][RPi4] - RTC/HWCLOCK not working

These days,while checking various logs i noticed that all the logs from before the network time sync are wrong (that's normal,RPi doesn't have RTC) so i remembered that i still have a DS3231 module around the house and decided to hook it to my RPi4.

So after adding dtoverlay=i2c-rtc,ds3231 and rebooting LibreELEC i proceed with the hwclock .using hwclock -w and rebooted ,this time with no network cable attached,but unfortunately the time and date were completely wrong.

LibreELEC:~ # journalctl | grep hwclock
Mar 11 09:33:35 LibreELEC systemd-udevd[336]: rtc0: Process '/sbin/hwclock --hctosys --utc --rtc=/dev/rtc0' failed with exit code 1.

LibreELEC:~ # hwclock --hctosys --utc --rtc=/dev/rtc0
hwclock: settimeofday: Invalid argument

And this is the hwclock -r  output.notice that RTC time is UTC

Quote

LibreELEC:~ # hwclock -r

Sun Mar 27 12:18:34 2022 0.000000 seconds

To make sure that everything is fine with the hw,i tested the module on Raspbian OS (bullseye) and there everything worked as intended (see image),after rebooting the OS without network ,RTC time (UTC) was used and adjusted according to my TZ.

Note: I also tested on LE 10.2 and it's not working either.

Ok,after more testing i managed to gather more informations.

1) It seems that LibreELEC it's using busybox's hwclock

2) Libreelec use /usr/lib/udev/rules.d/80-clock.rules but current hwclock can't handle that command

ACTION=="add", SUBSYSTEM=="rtc", RUN+="/sbin/hwclock --hctosys --utc --rtc=/dev/%k"
ACTION=="add", ENV{MAJOR}=="10", ENV{MINOR}=="135", RUN+="/sbin/hwclock --hctosys --utc --rtc=/dev/%k"

3) I disabled hwclock in busybox target configuration and enabled it in sys-utils

LibreELEC:~ # /sbin/hwclock --help


Usage:
hwclock [function] [option...]


Time clocks utility.


Functions:
-r, --show           display the RTC time
--get            display drift corrected RTC time
--set            set the RTC according to --date
-s, --hctosys        set the system time from the RTC
-w, --systohc        set the RTC from the system time
--systz          send timescale configurations to the kernel
-a, --adjust         adjust the RTC to account for systematic drift
--predict        predict the drifted RTC time according to --date


Options:
-u, --utc            the RTC timescale is UTC
-l, --localtime      the RTC timescale is Local
-f, --rtc <file>     use an alternate file to /dev/rtc0
--directisa      use the ISA bus instead of /dev/rtc0 access
--date <time>    date/time input for --set and --predict
--delay <sec>    delay used when set new RTC time
--update-drift   update the RTC drift factor
--noadjfile      do not use /etc/adjtime
--adjfile <file> use an alternate file to /etc/adjtime
--test           dry run; implies --verbose
-v, --verbose        display more details


-h, --help           display this help
-V, --version        display version

4) With the new hwclock binary the command works just fine

LibreELEC:~ # /sbin/hwclock --hctosys --utc --rtc=/dev/rtc0 --verbose
hwclock from util-linux 2.37.4
System Time: 1648402402.545322
Using the rtc interface to the clock.
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
ioctl(3, RTC_UIE_ON, 0): Invalid argument
Waiting in loop for time from /dev/rtc0 to change
...got clock tick
Time read from Hardware Clock: 2022/03/27 17:33:23
Hw clock time : 2022/03/27 17:33:23 = 1648402403 seconds since 1969
Time since last adjustment is 1648402403 seconds
Calculated Hardware Clock drift is 0.000000 seconds
Calling settimeofday(NULL, 0) to lock the warp_clock function.
Calling settimeofday(NULL, -180) to set the kernel timezone.
Calling settimeofday(1648402403.000000, NULL) to set the System time.

5) However the 80-clock.rules still fails so i had to use systemd as a workaround.

LibreELEC:~ # journalctl -b -o short-precise | grep hwclock
Mar 11 09:33:35.753542 LibreELEC systemd-udevd[339]: rtc0: Process '/sbin/hwclock --hctosys --utc --rtc=/dev/rtc0' failed with exit code 1.
Mar 11 09:33:45.004166 LibreELEC systemd[1]: Starting hwclock-start to read rtc and write to system clock...
Mar 27 20:42:27.001309 LibreELEC systemd[1]: hwclock-start.service: Deactivated successfully.
Mar 27 20:42:27.001775 LibreELEC systemd[1]: Finished hwclock-start to read rtc and write to system clock.

6) Initially i used After= sysinit.target but again,hwclock failed and i managed to get it working only after using After= kodi.target

[Unit]
Description=hwclock-start to read rtc and write to system clock
After= kodi.target

[Service]
Type=oneshot
ExecStart=/sbin/hwclock --hctosys --utc --rtc=/dev/rtc0

[Install]
WantedBy=basic.target

This workaround was just for testing and it work indeed,but it would be much better if we managed to fix the udev rule.

Yes, i will test it tomorrow and will return with feedback.

BTW, while i was testing the RTC thing, i noticed these 3 lines during shutdown :

systemd-shutdown[1]:Failed to set timeout to 10min:Invalid argument

failed to unmount /flash:Device or resource busy

systemd-shutdown[1]:Failed to finalize file systems, loop devices, ignoring.

Nope, no changes from me, those lines are there even after a clean install of LE11.

I don't remember if those were there prior to the systemd bump.

Another strange thing is that manually updating takes a lot longer than older LE11 builds and i'm using a SSD here. After "Update Kernel 100%" it seems to get stuck there for minutes.

Let me know if there's a way to debug the update process and will check.

HiassofT your test build works as intended,system clock is set correctly even if there's no network, confirmed by Kodi UI and dmesg log.

Thanks for the fix!

EDIT: I wonder if that slow update process that i'm seeing could be related to this - > https://github.com/raspberrypi/linux/issues/4930 <- even if im my case the system start just fine after the update is complete.

Perfect, thanks!

The "slow update" issue is new, on older LE11 builds update was very quick.

That kernel bug was fixed so it will be easy to check if that's the cause.

If it's still there, i will enable the cmdline debug. And i have several USB - SATA adapters to test.

Hopefully i will be able to find as many bugs i can with LE11, which probably will enter a "feature freeze" at some point! xD

Just finished testing on LE10,it's all good with your RTC fix.

LibreELEC (HiassofT): devel-20220328220759-4d9d4e2 (RPi4.arm)
LibreELEC:~ # journalctl | grep rtc-ds1307
Mar 29 00:02:39 LibreELEC kernel: rtc-ds1307 1-0068: registered as rtc0
Mar 29 00:02:39 LibreELEC kernel: rtc-ds1307 1-0068: setting system clock to 2022-03-28T21:02:39 UTC (1648501359)

No problem! With this occasion i've also tested the update process ,same SSD, SATA adapter and RPi4 as on LE11.....update only took a few seconds on LE10.

HiassofT just did a quick test with a LE11 build from 18/03/2022 (commit 5591832ae999f003bc53e3f7c15dc81c06c32413 ) ,which is the last commit before the RPi kernel bump and with this build the system update no longer stalls ,so this really seems a kernel issue .

I can confirm that using latest 5.15.y kernel (a51218097a20b10e4696fa19bef8bebf3833020) addresses the slow system update issue.(and i kind of hijacked my own thread )