We have an imx8m mini development board with pca9450(PMIC) and DDR3L. We use the following command to put it into suspend mode, but we cannot wake it up through the serial port(Debug port).
echo enabled > /sys/class/tty/ttymxc1/power/wakeup
echo mem > /sys/power/state
In suspend mode, the VDD_ARM voltage is 0V, NVCC_DRAM is 1.35V, VDD_SOC is 0.8V,VDD_GPU is 0.75V.
After entering any characters into the serial port, the VDD_ARM voltage is 0.9V, NVCC_DRAM is 1.35V, VDD_SOC is 0.85V,VDD_GPU is 0.95V.But the system hangs and no characters are output from the debug port.
How should we debug about resuming from suspend mode?
Is there any relevant guidance material?