Re: [PATCH] cpuidle: menu: allow state 0 to be disabled

[Rafael J. Wysocki]

On Mon, Jun 26, 2017 at 7:38 AM, Nicholas Piggin <npiggin@xxxxxxxxx> wrote:
> The menu driver does not allow state0 to be disabled completely.
> If it is disabled but other enabled states don't meet latency
> requirements, it is still used.
>
> Fix this by starting with the first enabled idle state. Fall back
> to state 0 if no idle states are enabled (arguably this should be
> -EINVAL if it is attempted, but this is the minimal fix).
>
> Acked-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
> ---
>
> Hi Rafael,

Hi Nick,

> This patch is helpful when measuring power draw of polling,
> latency cost of idle states, etc. Please consider merging if
> you agree.

I have a slight concern about x86 where state0 is mapped to polling
and the way it is used in general stems from that.

Still, I guess we can try and see if this causes any problems to
happen in practice, so I'm going to apply it.

Thanks,
Rafael