Regression on U-boot without batery [was: u-boot low-battery handling]

[Sean McNeil]

Andy Green wrote:
> Somebody in the thread at some point said:
> | 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.
>
> It'd be funny if the gsm resume issue is merely coming about through
> power world.
>
> Of all the things WLAN and GSM are the only ones that take serious
> power.  GSM at least is left on, hum.

It is really weird when I have the same software and do

echo 0 > /sys/bus/platform/devices/neo1973-pm-gsm.0/power_on

then put it to sleep it doesn't really go all the way to sleep. an ssh
via usb ethernet still works. But, if I do

echo 1 > /sys/bus/platform/devices/neo1973-pm-gsm.0/power_on

then put it to sleep it locks up. This is with the 2.6.26 kernel.

Sean