How to activate hibernation on STM32MP15X with embedded Linux?

RAhlb.1 · ‎2021-07-05

In our project we are currently trying to decrease boot time and energy consumption of an embedded linux running on an STM32MP153.

To improve energy consumption we are trying to activate hibernation, in order to test suspend-to-disk as well as the hybrid-sleep mechanism.

I have activated hibernation in the kernel and have also created a swap disk (which does not mount properly after reboot) by hand.

But still "/sys/power/state" gives me nothing more but "mem", indicating we can only do a suspend-to-ram and returns "not supported" for anything else i'll try to echo into it.

Is there a possibility to enable hibernation, even if the documentation does not list it explicitly?

Thanks in advance!

PatrickF · ‎2021-07-05

Hi,

as per AN5109:

"echo 'mem' > /sys/power/state

The 'disk', 'freeze' and 'standby' commands are not supported on STM32MP15x lines."

For sure, with some development, all should be possible (I'm not SW specialist).

Using LPDDR2 or LPDDR3 with STANDBY (no RETRAM), you could be below 500 uW typical power for STM32MP15x VDD + DDR (DDR power is dominant).

With a wakeup for Linux in less than 1sec.

See https://wiki.st.com/stm32mpu/wiki/How_to_define_your_low-power_strategy

Regards.

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

View solution in original post

PatrickF · ‎2021-07-05

Hi,

as per AN5109:

"echo 'mem' > /sys/power/state

The 'disk', 'freeze' and 'standby' commands are not supported on STM32MP15x lines."

For sure, with some development, all should be possible (I'm not SW specialist).

Using LPDDR2 or LPDDR3 with STANDBY (no RETRAM), you could be below 500 uW typical power for STM32MP15x VDD + DDR (DDR power is dominant).

With a wakeup for Linux in less than 1sec.

See https://wiki.st.com/stm32mpu/wiki/How_to_define_your_low-power_strategy

Regards.

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

RAhlb.1 · ‎2021-07-06

Hey,

thanks for the fast answer.

I must've overread the AN5109 part with /sys/power/state. Very unfortunate, but we should be mostly fine, even only with 'mem'.

I'll bring that recommendation into discussion the next time I have a HW specialist around me. That sounds promising, as we are at around 22 secs for a cold start right now. But first I have to fix another issue, as the Wireless LAN does not restart after a suspend.

PatrickF · ‎2021-07-06

For boot time, some generic information here https://wiki.st.com/stm32mpu/wiki/How_to_optimize_the_boot_time

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

PatrickF · ‎2021-07-06

In case of different issue (e.g. WLAN as you mention), maybe good to create another question thread.

Regards.

In order to give better visibility on the answered topics, please click on 'Select as Best' on the reply which solved your issue or answered your question. See also 'Best Answers'

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.