[ltp] Aggressive Powersaving

Pedro Ribeiro linux-thinkpad@linux-thinkpad.org
Tue, 9 Feb 2010 17:10:28 +0000

2010/2/9 Henrique de Moraes Holschuh <hmh@hmh.eng.br>:
> On Tue, 09 Feb 2010, Karsten K=F6nig wrote:
>> the new kernels really brought down the power consumption and I am inter=
>> in getting it a little bit further, on the road I don't use my DVD drive=
>> ExpressCard nor USB nor Firewire nor Touchpad, is there a way to cleany =
>> the power to these devices/buses?
> Yes. =A0Disable them on the BIOS where possible, Linux doesn't put PCI de=
> in D3 state yet as a rule, so once a driver loads and brings that device =
> D0 state, the device will stay powered up. =A0There might be exceptions.
> As for the DVD, eject the bay through sysfs (which will power it down wit=
> 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 acce=
>> 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. =A0Same for serial ports, =
> ports, the floppy controller, parallel ports...
> --
> =A0"One disk to rule them all, One disk to find them. One disk to bring
> =A0them all and in the darkness grind them. In the Land of Redmond
> =A0where the shadows lie." -- The Silicon Valley Tarot
> =A0Henrique Holschuh
> --
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Hi Henrique,

I read somewhere (forgot where) that sata power management shouldn't
be messed with in hot swappable devices. But maybe that is not true on
later kernels?

Actually now that I think about it, since I use the DVD drive quite
sparingly, do you think it is a bad idea to have it on min_power all
the time? Will it affect my ability to watch DVD's etc?

Many thanks,