[Gta04-owner] just a crazy idea to reduce power consumption

H. Nikolaus Schaller hns at goldelico.com
Sat Feb 17 13:30:12 CET 2018


> Am 16.02.2018 um 22:15 schrieb Andreas Kemnade <andreas at kemnade.info>:
> Hi,
> I have just a crazy idea to reduce power consumption:
> - use the 3G_WOE pin to decide between direct os boot (fit image)
>  or booting via uboot in spl.
> - boot an initrd wich contains just an app to answer phone calls.

You mean the Falcon mode? Yes, that seems to be doable.

Although one issue might be that the impulse at 3g_woe is limited
in length so it might already be too late to detect it as the wakeup
source. Or we must do a trick to enable it as edge detect interrupt
in parallel so that the impulse is latched.

But that might not even be necessary. If we can boot into an
initrd Linux in 1-2 seconds (which is what Falcon mode promises)
we can poll the Modem for incoming notifications.

> - suspend in spl before initializing ram. don't know if that
>  is feasible/possible... But then you will not have dram refresh
>  current during suspend.

Well, I think this is not easily done. SPL has no good suspend management...

> Well, it feels a bit like horrible hacking...

Indeed - but if we would want a really nice system we should squeeze
full Linux into 64k RAM and use it as SPL :)

> You probably need the right amount of alcohol intoxination
> to have the courage to try it but not too much that you cannot
> think anymore... ;-) Perhaps that level does not exist.

Well, the alternative would be to have some organization taking care
of any distractions - including any pressure to get it done :)

Something like



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