Power Saving modes on BBB?

[Gábor Paller]

"but IIRC you also need to switch off the PMIC and HDMI to further reduce
power consumption."

How do you switch them off? My understanding is that HDMI is powered down
if I don't use it. I don't have anything connected but the serial header.

Regards,
Gabor

On Thu, Jul 30, 2015 at 12:26 PM, <g4 at novadsp.com> wrote:

> Again not quite sure of the state of play with the current Snappy kernel
> but IIRC you also need to switch off the PMIC and HDMI to further reduce
> power consumption. The TI stuff may be doing this for you.
>
>
>
> Cpufreq-xxx looks good on 4.1 with (for example)
>
>
>
> ------------------------------snip--------------------------------
>
> root at arm:/home/debian# cat
> /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
>
> 1000000
>
> root at arm:/home/debian# cpufreq-set -f 300mhz
>
> root at arm:/home/debian# cat
> /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
>
> 300000
>
>
>
> *From:* Gábor Paller [mailto:gaborpaller at gmail.com]
> *Sent:* 30 July 2015 08:45
> *To:* Paolo Pisati
> *Cc:* jerry evans; Snappy Devel
> *Subject:* Re: Power Saving modes on BBB?
>
>
>
> 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.
>
> 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.
>
> Regards,
>
> Gabor
>
>
>
> On Fri, Jul 24, 2015 at 3:57 PM, Paolo Pisati <paolo.pisati at canonical.com>
> wrote:
>
> On Thu, Jul 23, 2015 at 6:27 PM, Gábor Paller <gaborpaller at gmail.com>
> wrote:
> > root at localhost:~# uname -a
> > Linux localhost.localdomain 3.19.0-18-generic #18-Ubuntu SMP Tue May 19
> > 18:34:38 UTC 2015 armv7l armv7l armv7l GNU/Linux
>
> I'm looking into this, but this is as good as upstream goes - if you
> want better PM support you should consider using the official TI
> kernel:
>
> https://git.ti.com/ti-linux-kernel/ti-linux-kernel/trees/master
>
> albeit i'm facing problems there too.
>
> Can you open an LP bug for this so we track the development?
> Thanks.
> --
> bye,
> p.
>
>
>
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