[maemo-users] brightness Re: [maemo-users] Re: Storage/Sleep Issues..

From: Frantisek Dufka dufkaf at seznam.cz
Date: Thu Jan 25 14:08:09 EET 2007
Igor Stoppa wrote:
>> I thought it can be half of power 
>> consumption on such devices. It was like that on ipaq 3870 I had. I 
>> remeber something like 80mA when display off ~130mA minimum brightness 
>> ~200mA full brightness, ~300mA full brightness + 100%CPU (not sure about 
>> exact values, it is long time ago, it was available as file in /proc in 
>> Familiar linux). On N770 I cannot check easily since some parts of power 
>> management is ... guess what? There is this myth about hidden power 
>> management ;-)
> Nothinig prevents you from creating a sysfs entry wich returns 
> tahvo_get_backlight_level()
> or even a proc one, if you really are into that sort of thing.

There is such entry - /sys/devices/platform/omapfb/panel/backlight_level

I meant way to get discharge current from battery circuit to know what 
is actual consumption of the device and how big is the influence of 
various parts. This is easy to get on laptops and it was possible on 
iPAQ but is currently kept very close to Nokia's chest. Yes one can 
measure it but it would need some tools, reading some register is much 
easier. Would be also good guide for programmers implementing proper 
idle state.

I would be interested in difference betwen SD/MMC vs internal flash I/O 
(i.e. how does rootfs on MMC affect battery life) but other things are 
equally interesting to know (wlan transmit/receive, sound, DSP on, DSP 
vs main CPU doing similar stuff ...).


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