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

Christ van Willegen cvwillegen at gmail.com
Wed Oct 7 23:33:29 CEST 2015


On Sat, Oct 3, 2015 at 5:16 AM, Neil Brown <neilb at suse.de> wrote:
> 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
> 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
> 36420 uA over 300 seconds
> 36420 uA over 300 seconds

Is this with the same bootloader on both test trials?

Does setting pinmux, GPIOs, etc (anything that influences power usage)
via 'a few' Linux kernel calls?

If so, is it possible to do logging (via RS232, since that _is_
available...) of the settings that are set via those kernel calls, so
that the two can be compared?

If you can switch back and forth between two kernel versions, and get
higher and lower readings consistently, it's not the hardware, but the
software that is incorrectly addressing the hardware. If logging is
possible, it is possible to see the difference in setting (or order of
setting) hardware parameters, and fix the software accordingly.

Is this too short-sighted?

Christ van Willegen
-- 
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