[ltp] Aggressive Powersaving

[Henrique de Moraes Holschuh]

On Tue, 09 Feb 2010, Karsten König wrote:
> the new kernels really brought down the power consumption and I am interested 
> in getting it a little bit further, on the road I don't use my DVD drive nor 
> ExpressCard nor USB nor Firewire nor Touchpad, is there a way to cleany cut 
> the power to these devices/buses?

Yes.  Disable them on the BIOS where possible, Linux doesn't put PCI devices
in D3 state yet as a rule, so once a driver loads and brings that device to
D0 state, the device will stay powered up.  There might be exceptions.

As for the DVD, eject the bay through sysfs (which will power it down with
the device still inside), and tell the kernel to put the SATA link in the
highest power saving mode (sysfs again).

> I don't know about VGA and modem, but I think they aren't that easy accessible 
> because they are part of the graphics driver and alsa (it does drive the 
> winmodem right?)

Disable the modem in the BIOS when not in use.  Same for serial ports, IR
ports, the floppy controller, parallel ports...

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh