Re: [PATCH V3] cpuidle/governors: Fix logic in selection of idlestates

From: Arjan van de Ven
Date: Tue Feb 04 2014 - 09:52:34 EST

On 2/4/2014 12:35 AM, Preeti U Murthy wrote:
The cpuidle governors today are not handling scenarios where no idle state
can be chosen. Such scenarios coud arise if the user has disabled all the
idle states at runtime or the latency requirement from the cpus is very strict.

The menu governor returns 0th index of the idle state table when no other
idle state is suitable. This is even when the idle state corresponding to this
index is disabled or the latency requirement is strict and the exit_latency
of the lowest idle state is also not acceptable. Hence this patch
fixes this logic in the menu governor by defaulting to an idle state index
of -1 unless any other state is suitable.

state 0 is defined as polling, and polling ALWAYS should be ok

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