Description:
I've got 3 watt more power consumption on my laptop when using an 3.0.X Kernel.
It's always 3 watt more usage regardless of the use case (idle, cpu usage, gpu usage, wlan, disk access).
Just constant 3 watt more usage with the new kernel.


Additional info:
* package version(s)
affected:

linux-3.0.4-1-x86_64
linux-3.0.6-1-x86_64
linux-3.0.6-2-x86_64

not affected:
kernel26-lts-2.6.32.46-1-x86_64
kernel26-2.6.39.3-1-x86_64


* config and/or log files etc.

Laptop: Asus U36SD

----------- kernel 3.0 -----------

$ uname -a
Linux u3 3.0-ARCH #1 SMP PREEMPT Tue Aug 30 08:53:25 CEST 2011 x86_64 Intel(R) Core(TM) i5-2410M CPU @ 2.30GHz GenuineIntel GNU/Linux

$ cat /sys/class/power_supply/BAT0/power_now
10290000

----------- kernel 2.6 -----------

$ uname -a
Linux u3 2.6.32-lts #1 SMP Tue Aug 30 08:59:44 CEST 2011 x86_64 Intel(R) Core(TM) i5-2410M CPU @ 2.30GHz GenuineIntel GNU/Linux

$ cat /sys/class/power_supply/BAT0/current_now
7714000

---------------------------------

Steps to reproduce:

Both measurements above happened during idle with hdd spinned down and led bright to lowest with the exact same system, just reboot and select the other kernel in grub. Run powertop and enable every "tunable". Turn off discrete nvidia graphic card with acpi call.
The measurement fluctuate every time a bit (max +/-0.5 w) but in the mean it's a 3 W difference (8 -> 11 W in idle and 10 -> 13 W while browsing).

Both kernel use C7 state as expected, use sata-link power management, audio power management, wireless power saving, usb autosuspend, bluetooth turned off, frequency switching (ondemand) and any other thing I can imagine. They even have the same amount of wakeups/second.

I guess that the new kernel just don't turn off some chip or doesn't make usage of some power saving, but I've got no idea how to figure out where it comes from.