RTC:The time is incorrect after each restart

Topics about the Hardware of Revolution Pi
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huanghuapan
Posts: 30
Joined: 03 Sep 2018, 10:01
Answers: 0

RTC:The time is incorrect after each restart

Post by huanghuapan »

Hi Sir:
We use the Revpi core3+,but we find the time is incorrect after each restart,the system is stretch 9.8.Now we cannot access the hardware clock.read time faild: Invalid argument.
Do you know the reason?
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zhan
Posts: 52
Joined: 16 Apr 2019, 13:31
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Re: RTC:The time is incorrect after each restart

Post by zhan »

Hi Huanghuapan,

this happens while linux is trying to read the time on the rtc device.
It might be caused by the damage of the devicetree, or fault of hardware.
Could you please post the output of following commands for the further debugging:
cat /proc/devices
cat /proc/driver/rtc
ls -l /dev/rtc*
sudo timedatectl
dmesg # executed after timedatectl and cat
tree /proc/device-tree/
Simon
KarimS
Posts: 1
Joined: 16 Nov 2022, 08:28
Answers: 0

Re: RTC:The time is incorrect after each restart

Post by KarimS »

Hi Simon,

I think I have a somewhat related issue with the hwclock. I cannot discern whether it is a software or hardware issue.

This I get when trying to access the hwclock:

Code: Select all

pt_linux@RevPi35313:~ $ sudo hwclock --verbose
hwclock from util-linux 2.33.1
System Time: 1668522779.433151
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.
The kernel buffer has the following entries:

Code: Select all

pt_linux@RevPi35313:~ $ sudo dmesg | grep rtc
[    2.199580] rtc-pcf2127-i2c 1-0051: pcf2127_rtc_read_time: read error
[    2.201225] rtc-pcf2127-i2c 1-0051: rtc core: registered rtc-pcf2127-i2c as rtc0
[    2.204321] rtc-pcf2127-i2c 1-0051: pcf2127_rtc_read_time: read error
[    2.205838] rtc-pcf2127-i2c 1-0051: hctosys: unable to read the hardware clock
[    2.209365] rtc-pcf2127-i2c: probe of 1-0051 failed with error -121
And running the suggested commands from the previous post yields the following:
https://support.plassertheurer.com/ws/? ... c24f5fd374
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nicolaiB
KUNBUS
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Joined: 21 Jun 2018, 10:33
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Re: RTC:The time is incorrect after each restart

Post by nicolaiB »

Does this error persist, after the system was powered up for a while? If not this is probably because of the super capacitor was not charged fast enough (mostly due to longer time off).

Nicolai
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