linux-kernel - Re: [PATCH 1/2] ARM: cpuidle: fix !cpuidle

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Date:	Wed, 30 Mar 2016 10:41:09 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Jisheng Zhang <jszhang@...vell.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Catalin Marinas <Catalin.Marinas@....com>
Cc:	linux@....linux.org.uk, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] ARM: cpuidle: fix !cpuidle_ops[cpu].init case during
 init

On 03/30/2016 10:17 AM, Jisheng Zhang wrote:
> On Wed, 30 Mar 2016 10:09:12 +0200 Daniel Lezcano wrote:
>
>> On 03/30/2016 09:16 AM, Jisheng Zhang wrote:
>>> Hi Daniel,
>>
>> [ ... ]
>>
>> Added Lorenzo and Catalin.
>>
>>>> Hi Jisheng,
>>>>
>>>> this should be handled in the arm_cpuidle_read_ops function.
>>>>
>>>
>>> Thanks for reviewing. After some consideration, I think this patch isn't correct
>>> There may be platforms which doesn't need the init member at all, although
>>> currently I don't see such platforms in mainline, So I'll drop this patch
>>> and send out one v2 only does the optimization.
>>
>> There is an inconsistency between ARM and ARM64. The 'cpu_get_ops', the
>> arm_cpuidle_read_ops from the ARM64 side, returns -EOPNOTSUPP when the
>> init function is not there for cpuidle.
>
> yes.
> arm64's arm_cpuidle_init() returns -EOPNOTSUPP if init callback isn't defined
>
>>
>> I don't think it is a problem, but as ARM/ARM64 are sharing the same
>> cpuidle-arm.c driver it would make sense to unify the behavior between
>> both archs.
>
> yes, agree with you. From "unify" point of view, could I move back the suspend
> callback check and init callback check into arm_cpuidle_init() for arm as V1 does?

Why ? To be consistent with ARM64 ?


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