Few days ago Intel released PowerTOP utility which can be used to check what software takes most of power on device (x86 targetted but should works on other architectures too). During weekend I started it on my laptop and changed few things after that so it came from about 300 to less then 100 wakeups during X11 work and 70 when working in remote console over wifi (most taken by bcm43xx driver).
I do not remember how big impact it had on battery life because I mostly use this machine with AC connected and battery keep only 50% of original capacity (it is over 2 years old).
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it doesn’t work under Ubuntu whit the default kernel :(