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Summary

The Ubuntu Mobile Distribution will run on battery-powered devices. This makes power management critical. This specification lists the things that need to be addressed.

Rationale

Currently, Ubuntu is popular on laptops. With the increasing interest in mobile computing with the advent of Nokia´s internet tablets, Microsoft-Intel UMPCs and Intel´s MID initiative, battery life is becoming increasingly important. To be successful on these mobile platforms, significant work needs to be addressed toward increasing battery life. This work spans the whole stack from kernel to user-space.

Use Cases

• Be able to watch 3-4 hours of DVD on a flight without an extended battery

Scope

• Fix drivers to automatically put hardware to increasing levels of power save states based on multiple timeouts
• Fix bus drivers to automatically put buses into power save modes when no devices on the bus are active e.g. pci, usb, pcmcia
• Improve Linux driver model to allow control power control of individual devices to allow userspace to override the default policy of the driver
• Enable a tickless (dynamic tick) kernel to allow processor to stay sleep for longer periods

• Profile userspace with a powertop from Intel that lists offending processes that poll or set frequent timers and get them fixed

• Develop a library that allows timer wake ups to be synchronized for non-real time apps. Get KDE and Gnome communities to use these libraries

Design

Implementation

Outstanding Issues

BoF agenda and discussion

CategorySpec