i.Mx7D Power management

[sharmilad]

Hi.

I am using iMx7D for one of our custom product. We are running 5.10 kernel version. I want to enable power management feature for reducing the current consumption. I have enabled CONFIG_SUSPEND macro in kernel. I am able to put the system into suspend mode using echo mem > /sys/power/state command and able to wakeup the device using GPIO interrupt. But I dont see much reduction in current consumption of the device when in suspend mode. I see missing of pm-imx7.c and suspend-imx7.S files in arch/arm/mach-imx folder of my kernel directory. So Is these files mandatory for making the necessary changes for power management implementation?

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products,

Yes, these files are needed, power management driver executes imx6_suspend or imx7_suspend in IRAM when entering to DORMANT mode, that one you are using.

Probably there are missing configs, could you please share Power management options -> Power Management support and Power management options -> Suspend to RAM and standby?

Also, I understood that you did found cpu_idle, am I right?

Thank you,

Best regards

[sharmilad]

Hi igor,

Thank you for your reply. Yes, the configs are enabled. I have attached my linux defconfig file. Please check and let me know if anything I am missing. From your comment what I understand is since I do not have suspend_imx7.S file it is using imx6 files. Am I correct? If suspend_imx7.S and pm_imx7.c files are mandatory; then where will I get that for kernel v 5.10? Do you have any patch for this?

>>Also, I understood that you did found cpu_idle, am I right?

Not clear about this query.

[JosephAtNXP]

Hi,

No, i.MX 6 and 7 platforms have files that are named similar, the process is the same, use imx suspend file, you need imx7_suspend.

But I found out what the problem is, from a thread that a colleague of mine helped you with, it seems that the issue is that you need to add more steps to really get a low power consumption based on the app note provided by my colleague.

If you have any additional steps since that thread (based on the appnote) or any measurements for both states that differ from what you disabled, please provide it.

Summarizing, I'd really look into the appnote no achieve a low power consumption based only on your board, settings and differences. The files do exist, they aren’t in the fs. If you can enter into sleep mode and the defconfig looks alright. Thank you for the time provided.

Regards