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With power management getting better at the kernel and driver level we can start to rethink how power management can be presented to the user, and what reasonable defaults are. Considering the large number of Ubuntu users, we'd like to start moving to more aggressive power saving defaults to save energy.

Release Note

New with this version of Ubuntu, the default settings for power management now include suspend by default on systems that are known to have working power management. Also we are updating the suspend feature to allow for a configurable time at which the computer will switch from suspend to hibernate automatically.


Saving power is a good thing. Many users don't use power management features because those features are poorly implemented, or they don't think to turn them on. If we turn them on by default we can hopefully save a little bit of electricity on lots of computers.

Use Cases


We will start using the power management functionality that we have by setting the defaults to start using it. This will only be done with machines that currently have whitelisted FDI files in the system. While this is likely to be less than the number of machines that could benefit from these improvements, it creates a starting point for enabling functionality. It is likely that all machines shipped and certified with any major Linux distributor will be appropriately whitelisted, so this segment of machines is expected to grow significantly over time.


Determining Whitelist

The whitelist will be determined by looking at HAL, specifically the properties on If there are any properties that include "power_management.quirk" in their name we will include the machine on the whitelist. This includes "power_management.quirk.none" which we will assume that if it's set, someone has done this intentionally.



User settings will not be migrated, and will be kept how the user has set them previously. There will be no migration.

Test/Demo Plan

We can test many of these as unit tests, and that shouldn't effect the other parts of the system. But, the most important testing will be getting this into Ibex as soon as possible to allow a wide amount of testing on a variety of machines.



DesktopTeam/Specs/PowerManagementSettings (last edited 2008-08-06 16:14:04 by localhost)