Management of Power Management ;)

Paul Fertser fercerpav at
Sat Aug 22 11:13:48 CEST 2009

On Fri, Aug 21, 2009 at 07:17:12PM -0700, Svetoslav Trochev wrote:
> Paul Fertser wrote:
> > BTW, for a start you can fix SD power control issues (due to a bad
> > merge the function got fubarred), if you run with SD inserted you'll
> > have extra ~20mA feeding card even in suspend.
> >   
> Today I have build my self a current probe for my Neo1973 and did some
> measurements. Here are my results
> 1. Bootloader (splash screen): 0.30-0.32A
> 2. Kernel loads: 0.22-0.28A
> 3. SHR loaded and GSM registered to the network: 0.26A and 0.28A if I
> have uSD card inserted.
> 4. SHR with LED backlight off: 0.18A and 0.19-0.20A with uSD

This all corresponds with what i heard about the device so far.

> 5. SHR suspend, GSM on: 0.08A

This one looks strange, guys measured it to be ~45mA with uSD inserted and
~25mA without.

> 6. Neo1973 shutdown from SHR power menu: 0.03A (BAD. I thing the GSM is
> still on)

Yes, it's still on, known problem. We're waiting for Mickey's fix. The
problem is that frameworkd "forgets" to turn the modem off (gta02 has a
hardware switch but for gta01 software needs to write AT at POFF several times
to reliably turn the modem off). And it still looks too much, the expected
modem current is about 8mA.

> The max charging current I measured is 0.32A with 50% discharged battery
> and SHR in suspend mode.

Considering the limit is 500mA and suspend current according to your
measurements is 0.08, it looks like 100mA went nowhere. Weird.

> The charge current after I disconnected the battery for 20s is as
> expected 0.10A. One problem I notice is that u-boot 1.3.1 will power on
> the phone as soon the battery voltage rises. So if you have dippy
> discharged battery the boot might fail and device will hang and draw
> residual current and it will drain the battery even dipper. I believe
> the old u-boot never powered on the phone automatically.

It's supposed that all charging should be done with Linux running, at least
that was the general idea at the time of development. The system should
ensure that it will never discharge the battery too much. Well, easier said
than done.

BTW, _never_ever_ take out the battery from gta01 running on USB power. It
will destroy it for sure if you don't pull of the cord immediately.

> this problems. I will need some help setting up my development
> environment. Currently I am running Ubuntu 8.04LTS.

For kernel hacking all you need is compiler, git and text editor. So, i'd
recommend to install emdebian (i think ubuntu is compatible with it), with
the help of emdebian install the toolchain, then git clone the sources from and start hacking.

Be free, use free ( software!
mailto:fercerpav at

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