"If you were hoping that the Linux 3.1 kernel would fix the big
power regression problem that's caused by PCI Express Active State
Power Management (ASPM) being disabled on more systems since the
release of the Linux 2.6.38 kernel, you're not in luck. There has
not been any active work in this area. Making things worse though
for mobile Linux users interested in a long lasting battery is
another new regression in the Linux 3.1 kernel.
Affected systems can easily see a 30% increase in power
consumption simply when comparing the Linux 3.0 kernel to the
current code being assembled for Linux 3.1.