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

Andreas Kemnade andreas at kemnade.info
Sat Feb 17 21:02:25 CET 2018


On Sat, 17 Feb 2018 13:30:12 +0100
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> Hi,
> 
> > 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.
> 
In some kind yes, in some kind no. Directly booting linux from spl:
yes, but not using it as a default boot, but only for the 3g_woe case.
And it should not be reconfigured at any time.

> 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.
> 
Hmm, is there only one pulse per incoming call?
Or multiple? I have to check.

> 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...
> 
Yes, on the other hand, there is not much to manage at that stage. If
you have nothing turned on yet, you do not need to care about turning
off stuff. 

Or we populate R1006 for wakeup.

Regards,
Andreas
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