Re: [PATCH V3 7/8] ARM: cpuidle: Register per cpuidle device

[Daniel Lezcano]

On 03/21/2015 09:35 PM, Lorenzo Pieralisi wrote:
> On Fri, Mar 20, 2015 at 11:44:00AM +0000, Daniel Lezcano wrote:
> > Some architectures have some cpus which does not support idle states.
> >
> > Let the underlying low level code to return -ENXIO when it is not
> > possible to set an idle state.
>
> Well, this is getting interesting. We are parsing possible CPUs to
> detect if they have common idle states in DT. If a CPU does not support
> idle states, the cpu node for that CPU should not define any idle
> state.
>
> The approach above will work with my heterogenous system patch, since
> the respective CPUidle driver mask will be created by parsing the DT
> idle states.
>
> http://www.spinics.net/lists/arm-kernel/msg403190.html
>
> In current approach if a "possible " CPU does not have idle states, we do
> not init CPUidle at all.
>
> So, to cut a long story short, what does "a cpu does not support idle
> states" mean ?
>
> Does it mean that firmware defines idle states for that CPU in DT but
> initializing them fail ?
>
> I am fine with this patch, but we need to define -ENXIO return properly.

Ok, I think that needs more discussion.

I will drop this patch from my patchset as we agreed on the other 
patches and resubmit.

  -- Daniel


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