My Linux distribution is Debian 10. When the computer has been asleep (suspend to RAM), it may wake itself in random period of time. I want to figure out what causes this behavior.

1 Answer 1


These are the options I know of from the top of my head:

  • RTC alarm: cat /sys/class/rtc/rtc0/wakealarm
  • Wake on LAN (WOL): ethtool …
  • Power up on Keyboard/Mouse activity
  • Power up after power loss
  • Power button press, obviously

All these options can be configured via BIOS/UEFI setup, only some can be read from within Linux, see this question.

Addendum: I just noticed dmidecode may include the information "Wake-up Type" (says "Power Switch" on my systems) in the section "System Information".

Anecdotal side-note: Ever since kernel 5.x, one of my systems has become a bit overzealous when it comes to the WOL feature. It wakes up on any network activity (e.g. broadcast), not only WOL packets directed to that very machine. I was able to alleviate this by explicitly selecting a different WOL method (magic packet).

  • Thanks for the replay. I have learned power up of a computer is prerogative of BIOS/UEFI, not OS. I figure out that my keyboard spontaneously sends signal to a computer. It remains to find out why it does. Sep 12, 2022 at 0:15

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