DART-MX8M suspend: Difference between revisions
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To measure SOM current consumption remove resistor R15 and connect ampere meter instead.<br> | To measure SOM current consumption remove resistor R15 and connect ampere meter instead.<br> | ||
It is recommended to boot from eMMC to get accurate measurement. | It is recommended to boot from eMMC to get accurate measurement. | ||
{{#ifeq: {{#var:HARDWARE_NAME}}|DART-MX8M|| | {{#ifeq: {{#var:HARDWARE_NAME}}|DART-MX8M|| | ||
{{Note|To achieve minimum power consumption during suspend it is necessary to remove two resistors on the Symphony-Board related to the Ethernet jack LEDs – R79 and R80.<br> | {{Note|To achieve minimum power consumption during suspend it is necessary to remove two resistors on the Symphony-Board related to the Ethernet jack LEDs – R79 and R80.<br> | ||
If assembled they back-feed the BASE_3V3 into the non-powered Ethernet PHY during suspend, increasing power consumption.}}}} | If assembled they back-feed the BASE_3V3 into the non-powered Ethernet PHY during suspend, increasing power consumption.}}}} | ||
Revision as of 12:52, 12 November 2020
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.
To suspend to RAM execute the following command:
# pm-suspend
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 "wakeup-source" 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 = <&gpio4 6 GPIO_ACTIVE_LOW>;
linux,code = <KEY_BACK>;
wakeup-source;
};
};
- Pressing the capacitive touch which has the "wakeup-source" property set in its device tree node, e.g.:
ft5x06_ts: ft5x06_ts@38 {
status = "disabled";
compatible = "edt,edt-ft5x06";
reg = <0x38>;
reset-gpios = <&gpio4 5 GPIO_ACTIVE_LOW>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_touch>;
interrupt-parent = <&gpio1>;
interrupts = <14 0>;
touchscreen-size-x = <800>;
touchscreen-size-y = <480>;
touchscreen-inverted-x;
touchscreen-inverted-y;
wakeup-source;
};
Measuring SOM current consumption in suspend
To measure SOM current consumption remove resistor R15 and connect ampere meter instead.
It is recommended to boot from eMMC to get accurate measurement.