sorry...erm ... ok let's see (after writting it and reading it, i'm afraid it didn't get much simpler, i hope it helps somewhat never the less)
provided your motherboard actually supports a software off feature then it has to do with your kernel configuration
If you motherboard doesn't support it, then you can't get it to work ... check the motherboard manual if it supports it ... if you have a cable running from you powersupply to the switch and LEDs at the front of the case, it doesn't support it (most likely)
Assuming that it does support it (in other words you can do it in Windows or another Linux distro)
You need to check that your kernel either has the feature statically compiled into it. or as a module, try running:
cat /boot/config | grep CONFIG_APM=
You will get something like this:
CONFIG_APM=m
an m at the end indicates it's a module, a y indicates it's static in the kernel. a # CONFIG_APM is not set means it's not available either way.
If it is a y or not set, you will need to recompile the kernel and toy with the settings that become available when you turn on APM
You do that by changing into the /usr/src/linux directory (or wherever you put the kernel source)
at this stage on that particular train of thought i have to say, good luck. saying yes to APM and leaving the subsequently available options as no should get it working unless you have a buggy BIOS. On that i can't offer advice
If it isn't compiled it, make it a yes, go to the main menu, save and exit
make dep clean bzImage
make modules
make modules_install
cp arch/i386/boot/bzImage /boot/vmLinuz_new
cp System.map /boot/System.map_new
edit /etc/lilo.conf to add an option to the newly compiled kernel
you'll need to add something like this:
image = /boot/vmLinuz_new
root = /dev/hda3
label = Linux_NEW
read-only
(the root = value is the same as the one that's already in the lilo.conf file for the existing kernel, in my case it's on the third hard drive partition)
leave are reference to the existing kernel in there, in case the new one doesn't boot, you can use the old one to get back into linux
if you are using GRUB find out what to do ... i've forgotten.
(if you don't know what you're using ... check during bootup, it should tell you when you see the menu asking you what kernel to load)
after you've edited and saved lilo.conf, exit the editor and run
lilo
and are now ready to reboot. (and if that fails curse my name ... so be careful
and check with other sources on what to do [this was a crash course])
Ok, now say it's a module, ie CONFIG_APM=m
all you need to is
modprobe apm
whilst superuser / root
and a shutdown -h now should turn your system off
NOTE
a full guide on how to compile a kernel can be found here:
http://www.linuxquestions.org/questi...threadid=49035
compiling a kernel ain't a big thing, but it can still throw you out ... i'm sure that forum gives a closer description.
The essence is, you need APM as a module, or statically compiled into the kernel.