Hello all,

I have just upgraded from Linux kernel 2.6.38 to Linux 3.0 by installing the .deb packages from Oneiric (new Ubuntu version), and I am experiencing a major drop in battery life (about 25% less time) on my laptop. It is also running noticeably hotter. Reverting to the older kernel brings back the good battery life and cool temperatures.

I need the 3.0 kernel because of some of the drivers it contains. Does anyone have any idea what to do to fix this power issue? Is the 3.0 kernel just supposed to be that much worse?

I'm running Xubuntu 11.04 64-bit.

Thank you!


Additional info:

sudo powertop yields the following interesting information:

Top causes for wakeups:
52.9% (317. [Rescheduling interrupts] <kernel IPI>

What is that?

You might search around the phoronix website for "kernel regressions". I recall some possible power related regression issues in July which were correctable by passing different kernel parameters at boot.

Thanks for the suggestion. I did try what they said, as well as some other things. Here were my results:

I tried all of the following kernel parameters (result in italics):

pcie_aspm=force
No improvement

acpi=noirq
No improvement

noapic
Command not recognized. Won't boot.

nolapic
Command not recognized. Won't boot.

acpi=off
No improvement

More ideas?

I have doubts that this directly helps the OP, but I want to draw attention to this blog post.

Essentially, this argues that there is no regression, but a bug fix that has some unfortunate side effects in some circumstances, and that there may be work-arounds, again, in some circumstances.

To summarise, it is a semantic argument; that is, it argues that to call it a regression is to misuse the term, in this case. (And, as far as can be told, the Phorons are pretty much unrepentant about their use of the word regression.)

While this doesn't affect the amount of power drawn by the OP's computer by even a milliampere, I tend to agree with the blog post (fewt) argument, but I will freely admit that if you are sitting in front of a computer that suddenly has half the battery life that it had previously, it will seem very like a regression.

I saw that recently as well and fully agree with your statement. I posted the Phoronix stuff back in August when the power issues were just coming around.

Here's hoping the brilliant kernel maintainers can figure out another way to handle this so there isn't a problem for some people. Or I can dream hardware vendors will quit doing stupid things - but that might be a pipe dream.