Christ van Willegen <[email protected]> writes: > On Sat, Oct 3, 2015 at 5:16 AM, Neil Brown <[email protected]> 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?
Yes. > > 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? pinmux settings can be read out of sysfs. It's been a while, but I'm fairly sure I looked into that. There aren't very many gpios, but I'm pretty use I considered each of them and found they were the same for both, or made no difference when toggled. > > 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? I have played some games like that: logging all writes to registers and looking for differences. There are an enormous number of differences and any that I actually looked into were inconsequential. Without some way to narrow the search space, it seems an intractable problem. The only thing I can think of would be a git-bisect. But that would require patching each intermediate kernel to get it working enough to boot/power-down-all-peripherals/test. That would take multiple weeks for full-time work (at a guess) and I'm not prepared to spend that - particularly as there is a rather large transition from board-file to devicetree and the difference could be hidden in there - not bisectable. NeilBrown > > Christ van Willegen > -- > 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0 > _______________________________________________ > Gta04-owner mailing list > [email protected] > http://lists.goldelico.com/mailman/listinfo.cgi/gta04-owner
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