IMX8QM-MEK Power Management difference between Linux and Android

[vinothkumars]

Dear NXP,

I got observation when I try to send  suspend-to-ram command ( echo mem > /sys/power/state ) from Android and Linux

Suspend to Ram in Android OS,

      L4.14.98

      # echo mem > /sys/power/state

      Application Processor going to suspend and resumed automatically

Suspend to Ram in Linux OS,

      L4.14.78 & L4.14.98

      # echo mem > /sys/power/state

      Application Processor going to suspend and wait for user press power key

Will you please give me the configuration or implementation to achieve the Linux level in Android ?

Thanks & Regards,

VinothS,

[vinothkumars · Accepted solution]

Finally I found wake-up API from power driver and disable it for disabling the auto wakeup.

Regards,

VinothS,

[smathe25]

Hi vinothkumars‌

Could you specify the driver you updated and changes you made to disable auto wake up.

[vinothkumars]

Sebimohan Mathew

Find my attachment.

Regards,

Vinoth S,

[smathe25]

Thank you so much vinothkumars‌

Have you ever tried GPIO pad wake up with some specific GPIO?

[vinothkumars]

Hi Sebimohan Mathew

Please find the document link,

iMX8QM-MEK: SUSPEND AND WAKEUP IN ANDROID 9 AUTOMOTIVE 

Best Regards,

Vinoth S,

[siva_prabhakara]

did u ever get any GPIO wakeup method to work?

[smathe25]

Follow this: How to add iMX8QXP PAD（GPIO) Wakeup . This worked for me

[vinothkumars]

Hi Sebimohan Mathew

I never tried with GPIO. But, some default wake-up already present.

Wake up done by following,

1. A53 debug UART
2. Power Key

• WAKE-UP

    1. BUTTON

         By pressing the power-key SW3 (0.5s)

     2. DEBUG UART

         Enable debug UART wake-up

         # cat ./sys/devices/platform/5a060000.serial/tty/ttyLP0/power/wakeup
         disabled

         # echo enabled  > ./sys/devices/platform/5a060000.serial/tty/ttyLP0/power/wakeup

         TO WAKEUP

                  Press the ENTER Key 2 times

Regards,

Vinoth S,

[igorpadykov]

Hi Vinoth

for Android supported power management one can refer to

sect.8.9 Power state configuration attached Android Guide.

from NXP Android documentation on link

Android OS for i.MX Applications Processors | NXP 

Best regards
igor
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[vinothkumars]

Hi igorpadykov‌

=> power 1 2

I tried Power control from car MCU console

is working, But, Sometimes the system wakes up by itself.

	Power control from car MCU console	Power control from car2 AP console	Comment
suspend	power 1 2	echo "1 2" > /sys/devices/ platform/vehicle-dummy/ power_req	The system disconnects from BT, waits for all tasks to be done, and then enter suspend mode. Press the power-on key to wake up the system. BT is connected again. Sometimes the system wakes up by itself.

Is there any possible to disable system wake up ?

Thanks & Regards,

VinothS,

[igorpadykov]

Hi Vinoth

one can look at power management differencies between android and linux

Linux Kernel and Android Suspend/Resume -blog archive 

Best regards
igor

[vinothkumars]

Hi igorpadykov‌

I validate the Linux L4.14.98 in imx8qm Mek board. There is no auto wake-up.

I compared the Linux pm driver source  with Android 9 automotive (L4.14.98) look like both are same.

Why android and Linux behaving differently when I write the power sate "echo mem > /sys/power/state " ?

Thanks & Regards,

VinothS

[igorpadykov]

Hi VinothS

>Why android and Linux behaving differently when I write the power sate "echo mem > /sys/power/state " ?

because power management is different in linux and android as described below

Linux Kernel and Android Suspend/Resume -blog archive 

Best regards
igor

[vinothkumars]

Thank you Igor for your quick reply,

Is it possible to configure Linux power management in Android ?

Thanks & Regards,

VinothS,

[igorpadykov]

Hi VinothS

this is general android question, suggest to post it on android forums:

Learn about our Developer community programs  |  Google Developers 

Best regards
igor

[vinothkumars]

Thank you Igor for the reply.

Thanks & Regards,

VinothS,

[vinothkumars]

Hi Igore,

Thank you for the quick reply. I checked the document and thank you for the document.

I needs to send power 1 2  (=> power 1 2) from M4 console to suspend Application Processor , Am I right ?

Thanks & Regards,

VinothS,