Linux/AM3354: Repeating log: "Time has been changed"

Nishihashi Naoya

Part Number: AM3354
Other Parts Discussed in Thread: TPS65910

Tool/software: Linux

Hi.

I am using ti-processor-sdk-linux-rt-am335x-evm-04.03.00.05.
Sometimes, I found repeating log every 5 seconds:

Welcome to Arago 2017.12!

[ 2.079130] systemd[1]: Set hostname to <am335x-evm>.
[ 2.347377] systemd[1]: [/lib/systemd/system/gadget-init.service:15] Unknown lvalue 'ExecStopPre' in section 'Service'
[ 2.600633] systemd[1]: Time has been changed
[ 2.605351] systemd[1]: Time has been changed
[ 2.609986] systemd[1]: Time has been changed
[ 2.614545] systemd[1]: Time has been changed
[ 2.619100] systemd[1]: Time has been changed
[ 2.623634] systemd[1]: Time has been changed
[ 7.027952] systemd[1]: Time has been changed
[ 7.032545] systemd[1]: Time has been changed
[ 7.037077] systemd[1]: Time has been changed
[ 7.041646] systemd[1]: Time has been changed
[ 7.046186] systemd[1]: Time has been changed
[ 7.050755] systemd[1]: Time has been changed
[ 7.055293] systemd[1]: Time has been changed
[ 7.059830] systemd[1]: Time has been changed
[ 7.064352] systemd[1]: Time has been changed
[ 7.068875] systemd[1]: Time has been changed

When shown this messages, Linux boot process is not progressed.
Not shown login prompt over taking 10 minutes...
Please give me advice for this problem.

Thanks in advance.
Nishihashi

over 6 years ago

0 Kemal R. Shakir over 6 years ago

TI__Guru 55345 points

Hello Nishihashi,

This message indicates that something is not okay with the RTC. If you use the AM335X on-chip RTC for time keeping, this would require RTC-only mode to keep the RTC working when power is off. See this table for the necessary connections: processors.wiki.ti.com/.../AM335x_Schematic_Checklist

Best regards,
Kemal

0 Nishihashi Naoya over 6 years ago in reply to Kemal R. Shakir

Intellectual 385 points

Hi,

Condition is following:
I found some boards says "Time has been changed," but another ones do not.
And it seems that the board which has NOT powered-up for about 1 week says it.

I designed as following:

Designed for RTC only mode
NOT using RTC only mode
Using external RTC (connected to I2C on AM3354)

My design is different from your checklist...
So, please check my schematics design (PDF file is attached below), and could you tell me something wrong in schematics?
(It is wrong to use external RTC in RTC only mode design. and so on...)

What is the direct cause to repeat "Time has been changed"?
(RTC state is not normal? Sorry, I have not understood yet...)

And, is there what I have to mind for using external RTC?

Best Regards.
Nishihashi

2311.schematic.pdf

0 Ahmad_Rashed over 6 years ago in reply to Nishihashi Naoya

TI__Genius 13567 points

Hello Nishihashi,

Did you follow figure 2 of the TPS65910A User Guide for AM335x? If you followed this guide then this is not a hardware problem.

If you are using an external RTC then please disable the internal one by adding this to your device tree:

&rtc {
	status = "disabled";
};

Then use "ls /dev/rtc*" to check if your external RTC is available.

0 Nishihashi Naoya over 6 years ago in reply to Ahmad_Rashed

Intellectual 385 points

Hi,

Thanks for advice.
I will check TPS65910 User Guide to decide this is not hardware problem.

And modify my device-tree.
(My device-tree is based on am335x-evm.dts : rtc status is not modified.)

This may be resolved.

Best Regards.
Nishihashi

0 Nishihashi Naoya over 6 years ago in reply to Nishihashi Naoya

Intellectual 385 points

Hi,

I have further question about this issue.
Some pins are connected differently from User Guide. The connections are below:

TPS65910 Pin	User Guide	My board
INT1	GPIO1_8	EXTINTn
sleep	GPIO1_9	GPIO3_19

1. Is this no relation for unusing Internal RTC?
2. If no, how should I modify my device-tree? If yes, will this be solved by previous reply?

Best Regards.
Nishihashi

0 Ahmad_Rashed over 6 years ago in reply to Nishihashi Naoya

TI__Genius 13567 points

Actually those pins are not used in the am335x-evm.dts. It appears they're not needed.

Processors

Processors forum

Linux/AM3354: Repeating log: "Time has been changed"