Regression on U-boot without batery [was: u-boot low-battery handling]
sean at mcneil.com
Tue Aug 26 07:19:04 CEST 2008
Andy Green wrote:
> Somebody in the thread at some point said:
> | Mike Montour wrote:
> |> Joerg Reisenweber wrote:
> |>> Powered via (this particular) 100/500mA USB-Host, none of both
> |>> U_Boot would boot without battery. Though it's happily working on
> |>> linux without GSM just on USB-power, after boot with battery.
> |> I have had some success (not all the time) running under Linux with
> |> USB power and no battery, but I had to turn off the charger through
> |> "echo 0 > /sys/.../chgmode" as well as turning off GSM.
> |> I have also found that WiFi stops working when the battery is removed,
> |> but it recovers when I re-insert the battery.
> | It occurs to me... Is it possible that even with the battery in that we
> | can get a brownout condition on resume?
> It's a good thought, but the brownout thing happens really early on
> startup before the CPU actually comes up. We definitely get that far.
Should be able to check easily using a battery simulator, programmable
power supply, and turning on all the devices. I have gps, gsm,
accelerometers, the works on when I suspend and can't resume. Most of
the time I can resume if I leave gsm off.
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