Power Management on Neo1973

Nils Faerber nils.faerber at kernelconcepts.de
Thu Jan 10 11:41:09 CET 2008

Nicolas Linkert schrieb:
> Hi,

> I certainly know that. But it says:
> - proper power management (i.e. no reasonable battery life yet)
> There is this tiny "yet". It suggests that it - the GTA01 - is going to
> have a reasonable battery life in the future. And that's not going to be
> the case.

Well, I am not the best person to comment on that but I will try anyway
to give my opinion on that based on experience with PM on mobile devices...

Getting the standby current right on a mobile device is a tremendously
tedious process involving a lot of work, a lot of testing, experience,
careful crafting of the suspend/resume paths in software, a proper
hardware design and proper hardware parts.

>From what I have seen in the kernel, all suspend and resume paths are
properly taken care of. If at all they need a little tuning but I am
pretty sure that 99% of what can be done is done. The NEO suspends to
RAM just fine and also wakes up fine, most devices inside powered down
during syspend.

There are hardware design issues reported by FIC/OpenMoko people that
are rumored to prevent real low-power standby - well, I think we cannot
help that, but I suspect this in the low <<5mA range we can expect to
save here.

The real power-eater right now, according to my measures, is the GSM
modem. And this also has been partially confirmed on the mailinglists.
If I remember correctly the current firmware of the TI modem does not do
proper active-standby modes (i.e. a low power mode but still being GSM
connected so that you can still receive calls and SMS). This causes a
power drain in the range of 10-20mA even in standby/suspend.

If you then calculate a 1200mAh battery and assume only 20mA total
standby drain this will "only" give you 60h or a little less than 3
days. If we could get this down to a total of 10mA, which is IMHO
realistic, this would already give you 5 days of standby. This is still
not very good but acceptable.

So buttomline is I would not see it *that* black. Let's hope for the new
modem firmware since the modem is currently the biggest standby current

> Best regards,
> Nicolas

> On Thu, 10 Jan 2008 10:02:47 +0000, "Maciej Kaniewski"
> <maciej.kaniewski at gmail.com> said:
>> Hi,
>> from openmoko.com shop page :
>> WARNING: Developers only! Please note that the OpenMoko products are not
>> meant for the end user and explicitly marked as Developer preview at this
>> time. Read this wiki
>> article<http://wiki.openmoko.org/wiki/Developer_preview>to find more
>> technical details of what you can and cannot expect of these
>> devices.
>> ... and when you follow the link you can find
>> ...
>> What you *CAN NOT* expect yet
>>    - reliable means of making phone calls, esp. not from the UI
>>    - reliable means of sending/receiving SMS, esp. not from the UI
>>    - integrated GPRS data access
>>    - bluetooth integration (basic bluez driver works)
>>    - proper power management (i.e. no reasonable battery life yet)
>>    - ringtone (or other) profile management
>>    - network preferences (call deflection, manual operator selection,
>>    ...)
>>    - a complete application framework where third party application
>>    developers can write apps that easily integrate with the OpenMoko
>>    world
>> As far as i know you had to agree with that  when you bought the phone
>> Maciej
> <snip>

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