Saving power by suspending Linux desktops and servers

One way to save power is to suspend systems early and often. That does not only include laptops (which nowadays support suspend-to-RAM by default under all operating systems when manually closing the lid) and mobile phones or tablets (which have typically been designed from the ground up to support suspend/wakeup cycles well), but also standard desktop-type systems and even servers. To make suspend usable, however, wakeup must be done quickly and as soon as there is any potential user interaction. Otherwise, automatic suspend after some (hopefully short) idle time will be disabled when it inconveniences users only in the slightest.On this page, I collect tips and tricks on how to enable automatic suspend and quick resume on Linux laptops and desktops, and aim to document how to do it even for servers. At this time, this page is not complete....

Enabling wakeup by USB device interrupt (e.g. from mouse or keyboard)

Execute the following, e.g. by adding it to /etc/rc.local at least once after each bootup:

        awk '/^USB.*disabled/ {print $1}' /proc/acpi/wakeup | while read dev; do echo $dev > /proc/acpi/wakeup ; done

This makes it as comfortable as Windows and MacOS to wake up a desktop computer where the power button is often hard to reach (hint taken from http://blob.inf.ed.ac.uk/chris/2011/03/04/linux-sleep-how-to-wake-with-a...).