Messages in this thread | | | Date | Fri, 16 May 2008 00:18:03 +0200 | From | Björn Steinbrink <> | Subject | Re: Strange C3/C4 sleep state behaviour |
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On 2008.05.15 23:11:00 +0200, Pascal Brückner wrote: > Hello! > > I'm recompiling my kernel recently to optimize the power usage of my > laptop (IBM ThinkPad X31). So far, my most efficient kernel at the > moment is a self-compiled 2.6.22 with phc patches for undervolting, > suspend2/tuxonice and hrtimers patches to force HPET on my ICH4-M chipset. > > Because everyone says, that newer kernel revisions are much more energy > efficient than my 2.6.22, i tried to compile one to reach at least the > energy usage of my recent kernel. > Sadly, this doesn't work because of only one issue: > With activated wireless networking (atheros chipset with recent madwifi > driver) i'm losing much energy due to the fact, that my cpu is > significant more in C2 state than in C3/C4.
Do you have CONFIG_CPU_IDLE enabled? That made a huge difference for me. Before that was available, _disabling_ CONFIG_NO_HZ also helped when wifi was enabled (but IIRC made things worse with wifi disabled).
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