Power Saving modes on BBB?

Gustavo Niemeyer gustavo.niemeyer at canonical.com
Thu Jul 30 08:59:48 UTC 2015

Can we somehow make better use of Gábor's feedback? Why are we doing so
poorly in terms of power usage?

TI's kernel is good because they take responsibility for their own product
working well. We are Canonical and should be responsible for Snappy being
superb as well, in my opinion.

On Thu, Jul 30, 2015 at 5:35 AM, Paolo Pisati <paolo.pisati at canonical.com>

> On Thu, Jul 30, 2015 at 09:45:25AM +0200, Gábor Paller wrote:
> >    Am I right that the entire cpufreq subsystem is also disfunctional on
> >    Snappy BBB?
> >    Snappy consumes 40% more current on idle prompt (boot completed, no
> user
> >    task is running) than the baseline TI SDK and I can't find the
> frequency
> >    scaling files under /sys.
> ubuntu at beaglebone:~$ cat
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
> conservative ondemand userspace powersave performance
> About the 40% more consumption, how did you get that number? same cpufreq
> governor? same config?
> >    Also, bizarrely, if the BBB is entirely shut down, Snappy still
> consumes
> >    around 120 mA while TI SDK goes down to almost 0.
> >    This, along with the lack of power-saving modes is pretty much a
> >    showstopper for any serious battery-operated application on Snappy.
> But yes, the TI BSP kernel is ahead in terms of support wrt power savings
> on the
> beeaglebone (after all it's their SOC and that's kernel they develop
> against...)
> compared to upstream (and that's the upstream that we track) - since you
> are so
> interested in the TI kernel and no one has done it yet, would you consider
> packaging
> it and releasing for the community as a kernel snap?
> I think Olivier or Ricardo can point you to the latest document
> showing how to do that
> --
> bye,
> p.
> --
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gustavo @ http://niemeyer.net
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