User Power Experience

This is an attempt at describing the different power states provided by the different OLPC devices.

Power States

The following table tries to describe what parts of a particular device are powered in a given state.

State:	Run	Idle	Screen Saver	Sleep	Off	Notes
XO-1
Proc	X
Memory	X	X	X	X
Display	X	X
Audio	X
Kbd/Tpd	X	X	X	X
WLAN	X	X	X	X		non-ideal
USB	X
State:	Run	Idle	Screen Saver	Sleep	Off	Notes
XO-1.5
Proc	X
Memory	X	X	X	X
Display	X	X
Audio	X
Kbd/Tpd	X	X	X	X		non-ideal
WLAN	X	X	X
USB	X					non-ideal
State:	Run	Idle	Screen Saver	Sleep	Off	Notes
XO-1.75
Proc	X	X	X	X		enters low power mode when not running
Memory	X	X	X	X
Display	X	X
Audio	X	X	X
Kbd/Tpd	X	X	X
Touchscreen	X	X	X
WLAN	X	X	X
USB	X	X	X
State:	Run	Idle	Screen Saver	Sleep	Off	Notes
iPad
Proc	X	X	na	X
Memory	X	X	na	X
Display	X	X	na
Audio	X	X	na	X
WLAN	X	X	na	X		bcast only ?

Terms

Run

This state is when the laptop is actively computing.

Idle

This state is when the laptop is not actively computing, and it has seen no recent (last minute) user input or network activity. In the XO-1 and XO-1.5, due to the high idle power of the x86 implementations, we suspend in the Idle state (powering off the processor).

Screen Saver

This state is when the laptop has seen no recent user activity. It should actually be orthogonal with Idle...

Devices

The following are the devices described in the tables:

Proc

Processor refers to both the actual central processing unit of the laptop, as well as the graphics subsystem and clock generator feeding the CPU and other subsystems.

Memory

Memory refers to the laptop's volatile storage.

Display

Display refers to the entire display subsystem, including the DCON (used to maintain a displayed image when the processor is powered off.

Kbd/Tpd

This refers to the keyboard and touchpad provided on the laptop.

WLAN

This is the wireless networking unit.