XO power management
pgf at laptop.org
Thu Mar 24 08:50:42 EDT 2011
> Hello everyone, I'm trying to perform some tests on XO battery life
> performance and I have some questions which I couldn't find a clear answer
> in the wiki or this list:
i'm sure richard will chime in, but here's a start.
> - When the battery level is "critically low" the OS (Sugar 0.88 based
> Dextrose) performs a safe shutdown. I would like to know what is the exact
> condition that triggers this.
the answer to this depends on what version of powerd is running. in
the latest powerd versions, we force a shutdown if the capacity is 1%
(or less :-), or if the battery voltage is 5.7V or less. we don't
bother with these checks unless the capacity is below 40% (which may
be a pointless optimization). these checks were slightly different
in powerd versions 27 and earlier, but i suspect dextrose is running
something newer than that.
> - Likewise, at some level controlled by the XO EC, the battery led light
> begins to flash orange/red. I would also like to know which is the exact
> condition that triggers this. Is it the SOC, battery voltage, ACR... ? And
i believe this value is 5.7V. (i.e., battery voltage)
> what level triggers this condition? I would also like to know the level in
> which the XO performs a "hard" poweroff.
5.5V on XO-1.5, 5.4V on XO-1.
also remember that the voltage at the battery will change, substantially,
between the suspended and running states -- so what the EC sees during
suspend may be several tenths of a volt higher during suspend than when
the system is running.
> Any help is appreciated.
> Ismael Schinca
> Centro Ceibal - Depto. Técnico - I+D
> Avda. Italia 6201 - Edificio Los Ceibos
> Montevideo - Uruguay.
> Tel.: 2601 57 73 Int. 2232
> part 2 text/plain 129
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paul fox, pgf at laptop.org
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