There is a solution for Active State Power Management -the problem of the Linux kernel, which ensures that laptops with the operating system in a considerably shorter battery life than the release of Linux kernel 2.6.38.
After the release of Linux kernel 2.6.38, discovered a lot of Linux users that the battery life of their laptop is significantly worsened. The issue played in all distros and was traced to a change in kernel 2.6.38, which ensured that the Active-State Power Management turned off as the bios of a system, its use is not explicitly allowed. Active-State Power Management or aspm is part of the pci-e specification, and the protocol ensures that system components use less energy when idle.
It turned out, however, that many systems do indeed aspm supported, without that this was to distract from the bios. The ACPI Description Table gave a large number of motherboards not indicate that the feature was supported, while this was the case. The enabling of aspm is to force it via the command “pcie_aspm=force” when booting the kernel, but this solution requires that the user already knows that he with the problems it faces, and the fix requires in addition the knowledge that many users do not have.
Actual solutions continued for many months, even after the release of the kernel versions 2.6.39, 3.0, and 3.1. Red Hat developer Matthew Garrett has now, however, a patch is proposed which lead to success and that mimics how Windows with feature handles. The patch ensures that the aspm turned off only when the platform emphatically pci-e manager allows. In other cases, the aspm is enabled, even if no explicit support for the feature is listed by the bios.
The first test of the site Phoronix shows, the energy consumption of a tested laptop is back at the level of Linux kernel 2.6.37 and earlier versions. Garret now has multiple patches released. The site notes that there are still other issues with regard to energy use in the kernel under the hands need to be taken.
