Is /sys/.../power/state supported ?

echo 3 > /sys/pci.../power/state  does nothing on my machine.
I have a PMac dual-G4 MDD, linux 2.6.14 and of course
CONFIG_PM and debug are enabled. It writes nothing in the
logs and the value it reads from any device/power/state is
always 0, no matter what I wrote into it. I wonder if it is
supposed to work, or if it not supported yet... or maybe if
I'm missing something.


--
Giuliano.