Seeed Studio SOM not behaving on shutdown

[BBeck.1]

I have a 3rd party SOM (seeed studio Odyssey). When I edit the .dts file in the tf-a-stm32mp1/fdts directory and add:

&pwr_regulators {
 system_suspend_supported_soc_modes = <
 STM32_PM_CSLEEP_RUN
 STM32_PM_CSTOP_ALLOW_LP_STOP
 STM32_PM_CSTOP_ALLOW_STANDBY_DDR_SR
 >;
 system_off_soc_mode = <STM32_PM_SHUTDOWN>;
 vdd-supply = <&vdd>;
 vdd_3v3_usbfs-supply = <&vdd_usb>;
};
 

When I try to do a "shutdown -h 0" i eventually get a WDT timeout.

One difference (from the DK2 board) is that they put the PMIC on i2c2 (rather than 4 or 6). Not sure if this is a red-herring or not.

Here is their meta layer: https://github.com/Seeed-Studio/meta-st-odyssey

Thanks,

Ben Beckwith

[BBeck.1]

I'm trying to debug the smcc calls which handle the suspend/shutdown messages. Any suggestions on how to debug this?

Thanks,

Ben