GTA series power design

Michael 'Mickey' Lauer mickey at
Tue Apr 1 17:43:11 CEST 2008

Dear Tony,

power management is an interesting cross-layer issue. Being a software
guy, I will only comment on this side.

> I saw Intel moblin ( has 
> some power management profile as interface for applications. Do we need 
> have smiliar design in hardware power bus and software profile parser 
> middleware?

One of the middleware projects I'm working on for Openmoko is API and
implementation for the open device daemon, see

> Question including:
> *What the bus will be used for devices, we have following device for GTA 
> series for sure
> **Bluetooth (USB/others?)
> **Accelerometer (SPI)
> **GPS (UART)
> **Debug (UART/Others?)
> **lots LED
> **Some mechanical button, some other types
> **Wolfson I2S
> **PMU I2C

Using e.g. the org.freesmartphone.Device.PowerManagement API you can
then turn on and turn off the devices via dbus.

(The next step on top of that would be a policy engine, so that you
could express rules like
 * turn on GPS every 10 minutes for until you have a fix,
 * turn off WLAN if idle for 2 minutes
 * turn on AUX LED on missed call or missed calendar event

> *Any power management project existing in open source project that could 
> suit for device power management?

There's a couple of approaches, including HAL, OHM, PolicyKit, and a
multitude of device-specific daemons. Neither one is ready to use nor
did it really take off. I think we should carry on the work @ for that.

N.B. there's also some proposals for the odeviced implementation in GSoC
-- it remains to be seen whether these are solid enough to be accepted.


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