IMX suspend Debian MX7

From Variscite Wiki
Suspend to RAM

1 Suspend to RAM

This state offers significant power savings as everything in the system is put into a low-power state, except for memory, which is placed into the self-refresh mode to retain its contents.

Note: by default power button on XFCE environment issues shutdown via logind.
if you want power key to be ignored by XFCE logind use below commands,

# sed -i 's/#HandlePowerKey=poweroff/HandlePowerKey=ignore/g' /etc/systemd/logind.conf
# systemctl restart systemd-logind

To suspend to RAM, run:

# pm-suspend

2 Wake up

There are many possible ways to wake up from suspend.
A few examples:
- Pushing the ON/OFF button (when present on the board)
- Pushing a button on the board which has the boolean property "gpio-key,wakeup" set in its device tree node (under gpio_keys), e.g.:

	gpio-keys {
		compatible = "gpio-keys";
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_gpio_keys>;

		back {
			label = "Back";
			gpios = <&gpio5 20 GPIO_ACTIVE_LOW>;
			linux,code = <KEY_BACK>;
			gpio-key,wakeup;
		};
	};

- Using the RTC you can wake at a specific time (see the RTC section)

2.1 VAR-SOM-MX7

Transistor Q1 should be shorted in order to measure the sleep current correctly. Please check out the CustomBoard schematics for additional information.