Power Management on i.MX8QM

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Power Management on i.MX8QM

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Senior Contributor III

Hi All,

I am working on IMX8QM-MEK with Android 9 Automotive. I checked some functionality, Power OFF/ ON and Reset by using switches (button).

And I checked the possible in software (only suspend is there) and only two functionality (mem, freeze) is there on the software side.

mek_8q:/ # cat /sys/power/state
freeze mem

And I checked the possible by using the hardware switch 

2.15. User interface buttons

There are two user interface buttons on the MEK board.

2.15.1.ON/OFF Button (SW3)

The chip supports the use of a button input signal to request main SoC power state changes (i.e. ON or
OFF) from the PMU.
In the ON state, if ON/OFF button is held longer than the 5 s, the power-off interrupt is generated. In the
OFF state, if ON/OFF button is held longer than the 0.5 s, the state will transit from OFF to ON.

2.15.2. Reset button (SW1)

In the ON state, holding the RESET button (SW1) will force to reset the power rails except the
VDD_SNVS on the i.MX 8QuadXPlus MEK board. The reset signal from SW1 is connected to the WDI
pin of the PMIC. Once the button is pressed, the PMIC will turn off the powers and generate a POR
signal to the processor and the peripherals. The i.MX 8QuadXPlus applications processor will be
immediately turned off and reinitiate a boot cycle from the OFF state.

I need to, how to test available functionality  (SUSPEND, RESUME) for power management for iMX8QM-MEQ.

Reference: https://www.nxp.com/downloads/en/schematics/SPF-29420_C4.pdf 

SW1 - Reset
SW2 - Boot configuration
SW3 - ON/OFF
SW4 - SCU_DBG_SEL (not sure what is this)

I need to know how to test the suspend and resume mode?

Is there any power management demo available for the imx8qm device?

Thank You,

Vinoth S,

Vinoth S
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6 Replies

92 Views
Senior Contributor III

How to configure user to control the sleep and wakeup by CAN or GPS Data ?

by using mem - able to sleep and wakeup the system.

Is there any configuration to control the sleep and wakeup functionality ?

Thanks & Regards,

Vinoth S,

Vinoth S
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92 Views
Senior Contributor III

Hi All,

I got some problem when using mem sleep mode,

mek_8q:/ # echo mem > /sys/power/state
[ 53.650292] PM: suspend entry (deep)
[ 53.655222] Freezing user space processes ... (elapsed 0.002 seconds) done.
[ 53.665245] OOM killer disabled.
[ 53.668495] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[ 53.677874] Suspending console(s) (use no_console_suspend to debug)
[ 53.694448] dpm_run_callback(): platform_pm_suspend+0x0/0x50 returns -16
[ 53.694453] PM: Device alarmtimer failed to suspend: error -16
[ 53.823125] PM: Some devices failed to suspend, or early wake event detected
[ 53.887293] PM: resume devices took 0.064 seconds
[ 53.914893] OOM killer enabled.
[ 53.918057] Restarting tasks ... done.
[ 53.923897] PM: suspend exit

What is the problem and How to avoid this?

Thank You,

Vinoth S,

Vinoth S
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92 Views
Senior Contributor III

Hi All,

following are the observation,

NORMAL:

VCC_MAIN - 1V
VCC_CPU0 - 0.9V

VCC_CPU1 - 0.9V
VCC_GPU0 - 1.09V
VCC_GPU1 - 1.1V

VCC_DDRIO0 - x
VCC_DDRIO1 - 1.1V
VCC_1V8 - 1.79V

VCC_3V3 - 3.29V

VCC_SCU_1V8 - 1.69V

# echo mem > /sys/power/state

SUSPEND:

VCC_MAIN - 1V
VCC_CPU0 - 0V

VCC_CPU1 - 0V
VCC_GPU0 - 0V
VCC_GPU1 - 0V

VCC_DDRIO0 - x

VCC_DDRIO1 - 1.1V
VCC_1V8 - 1.79V

VCC_3V3 - 3.29V

VCC_SCU_1V8 - 1.69V

Will you please guide me, to optimize the power still more.

Thank You,

Vinoth S,

Vinoth S
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92 Views
Senior Contributor III

Hi,

I have some doubt regarding suspend/ resume functionality.

1. How wakeup happening in IMX8QM-MEK when issue mem command ?

2. How to configure user to control the wakeup (Currently Head Unit will wakeup by internal timer) ?

Thank You,

Vinoth S,

Vinoth S
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92 Views
NXP TechSupport
NXP TechSupport

Hello,

 

Please try to enter into deep sleep mode with Android interface, like in the following:

Put Android to sleep for testing - Stack Overflow 

 

Hope this helps,

Best regards,

Aldo.

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92 Views
Senior Contributor III

Thank you Aldo for your reply.

Regards,

Vinoth S,

Vinoth S
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