[PATCH v2] Add cpuidle support for at91

[Albin Tonnerre]

On Wed, 30 Sep 2009 14:56 +0200, Nicolas Ferre wrote :
> Albin Tonnerre :
>  >> Just one precision: what is the difference, entering state0 with only
> >> the current cpu_do_idle() that is activated by default ?
> > 
> > Sorry, I don't get what you mean. Would you mind elaborating a bit?
> 
> I guess that during idle time, even without the cpuidle infrastructure,
> the SOC enters arch_idle() that calls cpu_do_idle().
> 
> So, now that I have your patch applied, I wonder what is the difference
> between the old situation and the first state of the cpuidle table.
> 
> In other words, only state "wait-for-interrupt *and* RAM self refresh"
> brings some more power saving. Indeed, cpu_do_idle() that correspond to
> the "WFI" state was already the way of dealing with idle cpu, even
> without your patch. Am I correct ?

Indeed, only the second mode brings us some gain.

Regards,
-- 
Albin Tonnerre, Free Electrons
Kernel, drivers and embedded Linux development,
consulting, training and support.
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 835 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20091009/20844aa2/attachment.sig>