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Automatic wake from suspend when power restored to laptop

rated 0 times [ 2] [ 0] / answers: 1 / hits: 2324 / 2 Years ago, wed, september 7, 2022, 6:40:56

I'm using a Chromebook with Ubuntu 14.04.2 LTS installed as an embedded system of sorts. I've figured out how to have it automatically suspend when disconnected from power by adjusting the power manager settings.

But I would like to find a way to have it automatically wake when power is restored.

If it isn't possible to detect that event and wake up, I also have a powered FTDI USB serial interface connected that could generate an event to wake on, but it doesn't appear in the list of /proc/acpi/wakeup devices.

Note that when I run upower -d, I see things that could be potential triggers. For example, device /org/freedesktop/UPower/devices/line_power_AC has a line-power/online field (set to yes when plugged in). Device /org/freedesktop/UPower/devices/battery_BAT0 has an on-battery field (set to no when plugged in).

I'm open to switching to a scenario where I automatically shutdown when the battery is low, if it's possible to configure the computer to automatically turn on when power is restored. I've seen it do that on occasion, but not reliably.

If it matters, I'm using a John Lewis ROM which boots Ubuntu through GRUB.

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ainlyyor

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1 Year ago

answered 2 Years ago barted · Accepted Answer

After further research, I found that I could get the desired behavior with my setup.

I went into the Power Settings and configured battery power as:

Suspend when inactive for: Don't suspend

When power is critically low: Power off

When the lid is closed: Do nothing

Likewise, when plugged in it's set to not suspend when inactive or the lid is closed.

To test, I unplugged the Chromebook and waited for the battery to get critically low and power off (overnight). When I reconnected power the next day, it automatically booted and all was good.

My previous tests had failed because I was shutting the system down manually, instead of having Ubuntu do it.

I was unable to find a solution using suspend and wake. It could potentially work with additional USB hardware with an ability to send a keyboard event to wake the Chromebook up when power is connected.