Rtcwake does not wake after Jetson Nano emmc went into mem state

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
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1

Hi

I am using Jetson Nano emmc version with Nvidia development board and trying to save power with rtcwake function.

I tried the commands below to make jetson nano sleep and wake up after 10 sec.
sudo rtcwake -v -u -s 10 -m mem
The jetson nano went into mem and woke up again after 10 sec. However, it went back to sleep again (the LED turned off and I couldn’t ping it anymore) after a few seconds and never woke up.
I will need to power cycle the unit to wake it up again. How do I make it stay waking up after the mem state?

Any input is appreciated.

3

hello YiCL,

please check developer guide, Chipset Power States for the supported power states.
you should refer to the available wake sources to awake Jetson from the deep sleep.
thanks

4

Hi JerryChang,

I issued the commands below.
sudo bash -c “echo date '+%s' -d '+ 20 seconds' > /sys/class/rtc/rtc0/wakealarm”

and tried both way to make my board goes into deep sleep
sudo systemctl suspend
$ sudo bash -c “echo mem > /sys/power/state”

However, I am still having similar issue. My Jetson Nano went into deep sleep mode and could not wake up again. I have tested 2 development board and 2 Jetson Nano emmc version. They all have the same behaviour. Is there any other way I can make this works?

Thanks.

5

hello YiCL,

please also share which JetPack release version you’re working with.
for example, $ cat /etc/nv_tegra_release

6

Hi JerrChang,
with cat /etc/nv_tegra_release, I got

R32 (release), REVISION: 5.1, GCID: 26202423, BOARD: t210ref, EABI: aarch64, DATE: Fri Feb 19 16:45:52 UTC 2021

I did more tests and realised sometimes sudo bash -c “echo date ‘+%s’ -d ‘+ 20 seconds’ > /sys/class/rtc/rtc0/wakealarm”
and sudo systemctl suspend worked as expected. However, sometimes the Jetson could not wake up.

Please let me know if there is anyplace I would need to modify to make sleep and wake up stable.

7

hello YiCL,

may I know the failure-rate.
could you please also setup serial console to gather bootloader logs when it’s not wake-up.
thanks

8

HI I could not replicate the error again. Now the wakealarm works as expected. Thanks for your help.

10

Hi Jerry,

I encountered issue that Jetson nano not waking up with rtc wakealarm and deep sleep again with a customised board.
Issued commands
sudo bash -c “echo date ‘+%s’ -d ‘+ 120 seconds’ > /sys/class/rtc/rtc0/wakealarm”
sudo bash -c “sudo systemctl suspend”
However, the jetson nano did not wake up.

With cat /etc/nv_tegra_release, I get

R32 (release), REVISION: 5.1, GCID: 26202423, BOARD: t210ref, EABI: aarch64, DATE: Fri Feb 19 16:45:52 UTC 2021

I have attached the log here.
log_jetson (16.9 KB)

Please let me know what might be the issue.

11

hello YiCL,

I saw lots of i2c transfer timed-out failures.
could you please confirm you’ve provide the regulator to those i2c device correctly.

BTW,
I think you’re having incorrect commands,
please try add 'now' into the pipeline for sending to wakealarm,
for example, date +%s -d "now + 120 seconds"
thanks