Is the C3 possible with SMP?

Alexander Motin mav at
Mon Nov 3 12:56:56 PST 2008

Alexandre "Sunny" Kovalenko wrote:
>>> When laptop is moving around with me, all USB modules are unloaded and I
>> I will try to unload USB later today.

I have got a bit power on disabling EHCI, but it could happen just 
because device itself went into the D3 state. C3 stats doesn't changes 
on that. UHCI and other devices disabling also gave some bits.

>>> get about 4 hours of battery life with wireless on, admittedly on the
>>> light usage (reading/writing E-mails, browsing web, typing up occasional
>>> document). I consider this good for 4.4lbs (<2kg) laptop.
>> I have a bit more then 3 hours at the same weight. Which CPU, video and
>> chipset do you have?
> This is CoreDuo T2400 with Intel 945GM video and Atheros 5212 a/b/g
> wireless part. One other thing, I forgot to mention is: I set 
> hw.pci.do_power_nodriver: 3

Thanks. With disabling everything possible I was able to reach 4 hours 

There is one question appeared, is there any way to deny driver 
attachment for some specific device to left it is D3 state? For example 
I don't need some specific USB hosts and PATA controller, but I can't 
disable them with just not loading the driver. There is alike DF_ENABLED 
flag I have found, but I haven't found any external way to reset it. :(

Alexander Motin

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