Re: Fighting for the power.

From: Alexander Motin <mav_at_FreeBSD.org>
Date: Mon, 04 May 2009 10:50:19 +0300
Hans Petter Selasky wrote:
>> 2. PCI devices
>> PCI bus provides method to control device power. For example, I have
>> completely no use for my FireWire controller and most of time - EHCI USB
>> controller. Disabling them allows me to save about 3W of power. To
>> disable all unneeded PCI devices you should build kernel without their
>> drivers and add to loader.conf:
>> hw.pci.do_power_nodriver=3
>> To enable devices back all you need to do is just load their drivers as
>> modules.
> 
> The new USB stack should turn off USB HC's automatically when not in use. At 
> least the schedules will get disabled. Did you do any research on this?

Sorry, I really was testing it only with previous USB stack. Now I can 
acknowledge, that new ehci module loading adds only 0.2W for me by 
default and almost nothing if I power down built-in USB2 web cam 
connected to it using `usbconfig -u 5 -a 2 power_off`.

Great! Thanks!

-- 
Alexander Motin
Received on Mon May 04 2009 - 05:50:24 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:47 UTC