I set up a number of systems, and I like to have them power off at system shutdown. Under the old IBM APM driver and the new eCS ACPI/APM drivers, I usually could get this to happen.
But on more modern systems, I've been seeing a new behavior on power off. The system powers off as I think it should, but then it wakes up one or two seconds later. One system needed to have jumpers reset on the motherboard relating to powering up in response to a USB peripheral.
Now on my latest system, based on an Intel G41 chipset, nothing in BIOS nor any jumper on the motherboard make any difference. The system always wakes up after a power off. Nothing on the interwebs suggests that Linux or Windows have any problem shutting the system down.
Even poweroff.exe supplied with ACPI 3.14 does not avoid wake after power off.
Any ideas why this is happening? Does anyone have a ticket already with this problem?