[Bug 891] Don't power anything up if battery is critical and charger is inserted

bugzilla-daemon at bugzilla.openmoko.org bugzilla-daemon at bugzilla.openmoko.org
Sat Sep 29 12:59:53 CEST 2007


------- Additional Comments From speedevil at mauve.plus.com  2007-09-29 12:59 -------
To do this right:
U-boot should:
Boot to slow mode, not fast mode (lower power, higher chance of not immediately
crashing out)

Extremely low batt: - under 2.9V, USB power on. 
Turn off immediately, charge at low-rate, set RTC to wakeup in 2 min.

Low bat - V under 3.1V, USB power on:
  Connected to USB bus in suspend.
     Attempt to wake host.
        Wake fails: beep to indicate state, power off.
        Wake succeeds: next state

Connected to USB bus not in suspend:
  Attempt to negotiate for 500mA as a HID device
    Negotiation succeeds - high speed mode, boot.
    Negotiation fails: beep to indicate state, power off.

Connected to something that is not a USB host in operational or suspend mode:
  Check we have not tried high power mode in last minute.
    If this has failed, then beep to indicate low-rate charge, power off.
  Record that we're trying high power mode at time now.
  Turn on high power mode, verify power stays stable for 10s.
  High speed, Boot.

All of this happens _before_ the u-boot bootsplash screen.
These thresholds should be set so that they will work with a year old battery,
with increased ESR and lower capacity than the 

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