I have an ssh connection to a linux machine which is hibernated after some non-activity time.
I want to make it resume, how do I do that? (writing to /dev/mouse to simulate mouse movement didn't do the trick)
+2
A:
A machine that is hibernating cannot come out of sleep without pressing the power button, or sending a magic packet if the ethernet adaptor has Wake On Lan (WOL) capability and the motherboard supports that. WOL packets can only be generated on the local network, not remotely from other networks.
Adam Davis
2009-02-26 19:06:39
but if I'm root on the machine - can't I simulate such activity?
akiva_eshbal
2009-02-26 19:08:32
In hibernate, the processor is HALTED, bus activity is stopped. How do you expect to be able to execute any code regardless of your user privileges? Are you sure the machine is hibernating, and not suspended?
Adam Davis
2009-02-26 19:11:12
I have an open ssh connection to the machine. I can execute programs.it is definitively NOT halted
akiva_eshbal
2009-02-26 19:52:39
Then it cannot be in hibernate or suspend. Exactly what do you mean when you say the computer is in "hibernate" mode? How do you know it's in that mode? What is the difference between "hibernate" and normal?
Adam Davis
2009-02-26 20:00:35
A:
In addition to what Adam has stated, some motherboards support waking from various states when an interrupt is triggered.
The key here is which state you are referring to as hibernation; are you talking about an extremely low-power mode in hardware, or software hibernation where core memory is written to disk and the machine is turned off completely? If the latter, WOL is the only possibility; if the former, than you can tell your motherboard to watch for interrupts from various sources and you can use some other means to trigger a wake-up.
A good starting point for reading is the Wake-On-LAN article on Wikipedia.
Michael Trausch
2009-02-26 19:13:22
1. the timeout until hibernation is software-configurable, so that I assume it *does* have a possibility to do the same as root.in addition, as I stated before - I do have an active ssh connection to the machine so it's no completely dead.WOL is disabled on that machine
akiva_eshbal
2009-02-26 19:19:29