Comment 96 for bug 39315

From what i can see, as others have stated, this is really a few different bugs, all with the same symptoms.

Mine is this one:
Affects: Users with Acer Laptops, or any other laptop manuf. that utilizes SBS (Smart Battery System)
Fix: Remove the SBS ACPI module (sudo rmmod acpi_sbs). Now while this is technically a fix, it leaves a bit to be desired, especially for people like me who actually use thier laptop as a laptop. What you CAN do, should you feel so froggy, you could recompile your kernel to use custom DSDT tables and do away with SBS entirely. There is a good guide to do this here:

http://forums.gentoo.org/viewtopic.php?t=122145

It was written for gentoo obviously, and on a gateway laptop, but with a bit of ingenuity you should be able to apply those instructions to ubuntu and acer. MAKE SURE YOU READ THE WHOLE POST BEFORE YOU RECOMPILE!!!!. Also, the original post is updated circa 2005, if something doesnt work for you there is plenty of good suggestions in the pages of responses.

Each of the bugs can be compounded upon each other, and starting out with a proper kernel always helps to avoid these things. The first thing everyone should do upon first install is open synaptic or run apt on the command line and install the proper kernel for thier architecture.

Extremely simple explanation of arch types:
i686 = intel procesors
i586 = AMD processors
either one comes in SMP version (multi processors), install this version if your processor is dual core, supports muti/hyper-threading or you just have multiple processors on your computer.