[Gta04-owner] [Community] GTA04 power management [was: About cost and business models for community hardware]

H. Nikolaus Schaller hns at goldelico.com
Wed Oct 7 14:29:38 CEST 2015


Hi,

Am 07.10.2015 um 14:18 schrieb Neil Jerram <neil at ossau.homelinux.net>:

> Something from LinuxCon that might possibly help with suspend power investigations: https://github.com/01org/suspendresume

Cool!

> 
> It's focus is on measuring and analyzing the speed of suspend and resume.  But I wonder if looking at the output might also reveal clues about something that is _not_ suspending properly (or at all).

Yes, from a rough look into it, it should be possible to trace which subsystems are really sent to suspend. If something is missing, it is a place for deeper digging.

BR and thanks,
Nikolaus

> 
> Regards,
> 	Neil
> 
> 
> On 07/10/15 09:06, H. Nikolaus Schaller wrote:
>> Hi Neil.
>> 
>> Am 03.10.2015 um 05:16 schrieb Neil Brown <neilb at suse.de>:
>> 
>>> "H. Nikolaus Schaller" <hns at goldelico.com> writes:
>>>> 
>>>> Could you share a complete description of your setup? So that it is reproducible?
>>>> I.e. which kernel, which user space, command to suspend/wakeup, boot loader
>>>> version, how you measure suspend current etc.
>>>> 
>>> My test board in a GTA04A3, though my GTA04A4 shows much the same sort
>>> of numbers.
>> 
>> There shouldn't be big differences (some A3 boards may have an additional LIS302)
>> 
>>> 
>>> 
>>> User space is Debian/testing ... possibly with a bit of
>>> Debian/experimental (it is listed in my sources.list but I don't
>>> remember why).
>>> 
>>> I have a few of my own tools running, but they are all idle while I test
>>> power usage.
>>> So screen is blank, sound is off, GPS is off etc.  There is no SIM card
>>> and I haven't tried to access the GSM module at all.
>>> 
>>> I use the following script while connected to the serial console.
>>> The script disables RS-232 (as the sucks several mA) and turns of the
>>> power source (my board is powered via a 5V source on the 'AC' pins of
>>> the serial connector).
>>> Then it checks the battery, suspends for 5 minutes (default), wakes up
>>> and checks the power usage.
>>> I run that several times and discard the outliers.
>>> 
>>> With a 4.2 kernel at:
>>>   http://git.neil.brown.name/?p=gta04.git;a=shortlog;h=refs/heads/4.2-gta04
>>> I get numbers like:
>>> 
>>> 46967 uA over 301 seconds
>>> 46967 uA over 301 seconds
>>> 46967 uA over 301 seconds
>>> 46967 uA over 301 seconds
>>> 46967 uA over 301 seconds
>>> 46967 uA over 301 seconds
>>> 46967 uA over 301 seconds
>>> 46967 uA over 301 seconds
>>> 47124 uA over 300 seconds
>>> 47124 uA over 300 seconds
>>> 47124 uA over 300 seconds
>>> 47124 uA over 300 seconds
>>> 47124 uA over 300 seconds
>>> 47124 uA over 300 seconds
>>> 47124 uA over 300 seconds
>>> 47281 uA over 299 seconds
>>> 47281 uA over 299 seconds
>>> 47600 uA over 297 seconds
>>> 
>>> 
>>> With the 3.7 kernel
>>> http://git.neil.brown.name/?p=gta04.git;a=shortlog;h=refs/heads/3.7-gta04
>>> I get:
>>> 
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21420 uA over 300 seconds
>>> 21709 uA over 296 seconds
>>> 23556 uA over 300 seconds
>>> 23568 uA over 300 seconds
>>> 36420 uA over 300 seconds
>>> 36420 uA over 300 seconds
>>> 
>>> 
>>> Disabling the RS-232 doesn't work on my 3.7 kernel (because the required
>>> GPIO isn't exported by the board file) so I have to unplug the RS-232 to
>>> get proper reading there, but I could easily fix that.
>>> 
>>> I'd be interested to hear what other people measure.
>> 
>> I have run a quick test with our Letux 4.3-rc4 kernel (on a GTA04A3 with
>> broken WiFi) and get readings ~170-190 mA.
>> 
>> Well, this is with backlight still enabled (we have no proper config for
>> that in our tree - it remains "white") and the red power button LED stays
>> on.
>> 
>> Backlight needs ~20mA at 18V which translates to ~100 mA (depends
>> on battery voltage). So this means the core goes down to less than
>> 70 - 90mA.
>> 
>> And, I did not take care of turning off everything yet. Just a first test.
>> 
>> Subtracting the red LED and some peripherals which may stay powered
>> makes you readings reasonable. But to really compare I would need a
>> better test setup (which also requires to be able to charge the battery without
>> downgrading the kernel).
>> 
>> One observation is that the RTC wakeup does not trigger. I have to wake
>> up by pressing the power button.
>> 
>>> If you don't have a serial port connected you probably need to arrange
>>> some way to start in from the touch-screen, and then make sure the
>>> screen turns off.
>>> 
>>> NeilBrown
>>> 
>>> Script is:
>>> #!/bin/sh
>> 
>> I had to replace by /bin/bash to make $[...] recognised.
>> 
>>> 
>>> # disable charging, suspend for 5 minutes and report apparent
>>> # power usage by monitoring battery.
>>> 
>>> power1=/sys/class/power_supply/twl4030_usb/mode
>>> power2=/sys/class/power_supply/twl4030_ac/mode
>>> chg=/sys/class/power_supply/bq27000-battery/charge_now
>>> rs232=/sys/class/gpio/gpio13/value
>>> rs232dir=/sys/class/gpio/gpio13/direction
>>> delay=${1-300}
>>> [ -f $rs232 ] || { echo 13 > /sys/class/gpio/export; echo high > $rs232dir;}
>>> 
>>> stty raw -echo -cread
>>> echo 0 > $rs232
>>> echo off > $power1
>>> echo off > $power2
>>> before=`cat $chg`
>>> start=`date '+%s'`
>>> echo $[start+delay] > /sys/class/rtc/rtc0/wakealarm
>>> echo mem > /sys/power/state
>>> after=`cat $chg`
>>> end=`date '+%s'`
>>> echo 1 > $rs232
>>> stty sane
>>> echo auto > $power1
>>> echo auto > $power2
>>> 
>>> echo $[(before-after)*3600/(end-start)] uA over $[end-start] seconds
>> 
>> 
>> BR and thanks for sharing!
>> 
>> Nikolaus
>> 
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