Linux sleep/suspend power mode not working

[golovdinov]

Hi!

Does anyone managed to make Linux sleep/suspend power mode works on a LicheeRV Nano?

There is Linux doc about it.

But by default, there is no /sys/power/state file (also /sys/power dir is missed).

Research leads me to the Milk-V forum thread. It seems sleep/suspend works on a Milk-V Duo 256m board with the same SG2002 as in LicheeRV Nano.

Here are Linux configs I managed to found:

# build/boards/sg200x/sg2002_licheervnano_sd/linux/sg2002_licheervnano_sd_defconfig
CONFIG_PM=y
CONFIG_PM_RUNTIME=y
CONFIG_PM_SLEEP=y
CONFIG_SUSPEND=y
CONFIG_SUSPEND_FREEZER=y

# build/boards/sg200x/sg2002_licheervnano_sd/sg2002_licheervnano_sd_defconfig
# both variants have no effect
CONFIG_KERNEL_SUSPEND=y
CONFIG_SUSPEND=y

After rebuild, /sys/power/state file appears, but it's empty. Also there are no anymore files in /sys/power dir.

Need help.

PS: I tried to force Linux CPU suspending with SG2002 registers, but after setting RTC_EN_SUSPEND_REQ to 1 (devmem 0x050260E4 32 0x1) the board instantly dies. So it's impossible to try to make next steps to implement suspending (write to req_suspend register and so on). But it's another story not connected to a Linux, I think.