Re: [PATCH v6 5/5] ACPI : enable ACPI_PROCESSOR_IDLE on ARM64

[Daniel Lezcano]

On 06/27/2016 05:03 PM, Sudeep Holla wrote:
> Hi Daniel,
>
> On 27/06/16 15:33, Daniel Lezcano wrote:
> > On 06/14/2016 04:48 PM, Sudeep Holla wrote:
> > > Now that ACPI processor idle driver supports LPI(Low Power Idle), lets
> > > enable ACPI_PROCESSOR_IDLE for ARM64 too.
> > >
> > > This patch just removes the IA64 and X86 dependency on
> > > ACPI_PROCESSOR_IDLE
> > >
> > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > > Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> > > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > > ---
> >
> > Hi Sudeep,
> >
> > now that ACPI processor supports ARM64 did you check the
> > CPUIDLE_DRIVER_STATE_START trick in the code and its derivative ?
>
> No, that is used only for C-State and ARM64 doesn't support it.
> Patch 1/5 puts all the C-State code under #ifdef so that it's not
> compiled on ARM64.
>
> > I deleted the patch 2/5 but there is a place where:
>
> Sorry, I don't follow what you mean by that.

I meant I just deleted from my mailbox the patch 2/5, so I can't do 
inline comment.

> > if (max_cstate=0)
> >      max_cstate=1;
> >
> > Probably this is because the POLL state is inserted, so there is always
> > an idle state. But for ARM, that is not the case.
>
> Yes
>
> > Also, there are some places where the idle state index begins to 1. I
> > think it should be 0 for ARM.
>
> Yes for LPI, it does start from 0.


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