Adding:
Code:
hw.pci.do_power_nodriver=3
to /boot/loader.conf can make battery life longer.
Devices which are not used eg. driver is
not attached to them, will not use any power.
Note that resuming from suspend will put all devices from D3 state to D0 (even one with driver not attached)
If you dont want that you can also add:
Code:
hw.pci.do_power_resume=0
Note that this may not work on some laptops, so please test it before use.
Unforunately dettaching driver from device (via kldunload) will not put it immediately into D3 state.
You can watch current power state of various devices with
pciconf(8) -c switch.