When I run 'halt' the kernel prints:
Halting.
Shutdown: hdc
ACPI: PCI interrupt for device 0000:01:05.0 disabled
ACPI: PCI interrupt for device 0000:01:04.0 disabled
ACPI: PCI interrupt for device 0000:01:03.0 disabled
ACPI: PCI interrupt for device 0000:01:02.0 disabled
Power down.
acpi_power_off called
But the system does not shut down. (The fans keep spinning, the LEDs keep shining, the LCD keeps displaying.) Basically, the motherboard is still providing power to every component, as if the power supply had refused to stop.
http://linux.kernel.free.fr/halt/config-2.6.22.1-rt9
http://linux.kernel.free.fr/halt/acpidump.txt
http://linux.kernel.free.fr/halt/dmesg.txt
http://linux.kernel.free.fr/halt/halt.txt
http://linux.kernel.free.fr/halt/lspci.txt