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Re: Power button not shuting down debian

On Fri, 2005-12-02 at 16:35 +1100, Neil Dugan wrote:
> Hi I have an old compaq computer, when it had Fedora on it I could do a 
> short press of the power button, and the computer would shut-down nicely.
> I have since upgraded to Debian, the problem is that pressing the power 
> button no longer shuts the computer down.
> Any help in this would be appreciated.

The PC is probably using a "modern" (ATX) architecture (modern is a
relative term here... :) ), meaning that the power button just sends a
signal to the motherboard. How the motherboard interprets this signal is
dependent on what you've told it. By default, the signal tells the
motherboard to shut down the power supply, thereby shutting the computer

But if you load APM or ACPI modules, the motherboard is told to ignore
the power button signal and just pass it on to the OS. The OS then
chooses what to do with the signal. (Usually put the computer into a
sleep mode.) At this point you usually need to hold down the power
button for 4-5 seconds to tell the system that yes, you really mean
power off, and you mean it NOW.

That's a pretty gross oversimplification, but that's basically what's

So then the answer to your question depends on what your question
actually is:

Q: How can I shut my computer off now?
A: Hold down the power button for a few seconds.


Q: How can I get the computer to shut off immediately when I push power?
A: Unload the APM or ACPI modules, if they're loaded (using modprobe -r
or rmmod).

Personally, I would strongly recommend the former. There's rarely a good
reason to disable power management features unless they're causing
stability issues. And in those cases you're usually better of changing
the mode of management used (APM or ACPI) instead of abandoning the
concept altogether.

Alex Malinovich
Support Free Software, delete your Windows partition TODAY!
Encrypted mail preferred. You can get my public key from any of the
pgp.net keyservers. Key ID: A6D24837

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