The proper ASPM fix devised by Red Hat's Matthew Garrett late in 2011 went into the Linux 3.3 kernel, which is still currently under active development. The ASPM fix has since been patched into the kernels of Ubuntu and Fedora, among other Linux distributions.
This testing has undergone enough testing and review now that it looks like it's did the trick to fix the PCI Express Active State Power Management regression for many systems.
Greg Kroah-Hartman, now at the Linux Foundation, is preparing a special Linux 3.2 stable release that simply incorporates this PCI-E ASPM change. "It's a bit different from other stable review cycles in that it only has one patch. It's a fix to decrease power consumption on a wide range of different machines. I wanted to make this a separate release to make it easier for people to test it out in a simple way. This patch has been shipping in the Fedora kernels for a while now, so I'm pretty confident about it, but I'm doing it this way just to be sure. Please let me know if anyone has any problems with it as soon as possible."
This ASPM-kernel-release will be the Linux 3.2.5 version as mentioned on the kernel mailing list.
The ASPM power regression is what I discovered in early 2011 and then subsequently automatically-bisected, among making other discoveries.