Comment 2 for bug 1011317

Have a look at https://bbs.archlinux.org/viewtopic.php?id=133541
There are some suggested fixes there (which worked on my HP Pavilion dm1), involving blacklisting the sp5100_tco driver and disabling the thermal module. However, it appears that a more recent update to the driver has introduced further problems for some people (although not me) - so the fixes may or may not solve you problem.