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I've seen hints at some kernel power bug affecting battery life if updating to 11.10 -- as for example here.

I relation to this, I have three questions:

  • How can I tell if my machine is affected after having updated?
  • What can I do to fix the problem?
  • Will these solutions have a negative effect if I'm not affected by the problem?

For example, will the proposed workaround from the link above have any negative consequences?

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What version are you upgrading from? That power drain issue has been present in the linux kernel for some time, so this would have affected you in 11.04 as well. – ImaginaryRobots Oct 17 '11 at 17:53
From 11.04. I'm unsure whether my less than optimal battery life is caused by old batteries (it could be) or by this problem. – Rasmus Oct 17 '11 at 20:55
up vote 1 down vote accepted
  1. AFAIK the easiest way is to install Windows, let the computer run while browsing some files and register average temperatures and fan speed. Then install Linux (don't use LiveCD) and do the same using the terminal command: sensors
  2. There is no real fix to the problem. Only partial solutions that will never let you come even close to what you'd have on Windows.

  3. I've never read about people killing their install testing those "fixes". You can easily add, during boot, the parameters for one session only by holding Shift key to bring up the GRUB and hitting E key to enter the appropriate menu. You can test whatever power related parameters you want this way and after successful testing - add them permanently to GRUB (see the link above)

Another way to verify the potential risk of your system being affected is to refer to Motherboards With Broken ASPM On Linux Posted by Michael Larabel on October 10, 2011

Remember, desktops and servers are affected as well!

Generally Phoronix seems like best resource to read about the subject.

EDIT: Re the point #2 - that's why you should vote "it affects me" here Second - the question title is a little bit misleading as the "power drain" started since kernel version 2.6.35 (source) and subsequent kernel releases added even more power-related regressions without solving the old ones (source: Phoronix).

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