M4 on i.MX 8QuadMax stops working when A-cores are put into Suspend-to-RAM mode

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I’m using echo mem > /sys/power/state to put the Linux into Suspend-to-RAM (DSM) mode. However, it causes the entire SoC to be suspended.

I cannot find any example code in the SDK_2_9_0_MIMX8QM6xxxFF to demonstrate such a feature. The only almost-relevant demo app is the power_mode_switch, and even that only demonstrates various sleep scenarios for the M4, not the A-cores.

I have already gone through some application notes, e.g. “i.MX 8M Low Power Design By M Core Running In System Suspend”, but that appears to be only applicable to the i.MX 8M series. Is there anything similar to the Low-Power Audio flags mentioned in this document, where it enforces the M4 to keep running while the Linux system is in DSM?

Thanks in advance.

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Hi @Cytoplasm3460,

In this case, we don’t have a proper answer. Usually, we just test some basic demos from NXP (e.g. peripheral access, remote proc, rpmsg…), we don’t have any tests right now related to suspend mode or power consumption. We do have plans to achieve that in the future.

In this case, I will recommend you check the NXP community: https://community.nxp.com/ (or any documents related).

Let me know if you find something or if you need any help with the device tree or driver setup.

Best Regards,
Hiago.

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