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

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Date:	Wed, 30 Mar 2016 16:43:42 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>
CC:	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Catalin Marinas <Catalin.Marinas@....com>,
	<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 Wed, 30 Mar 2016 10:41:09 +0200 Daniel Lezcano wrote:

> 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 ?

Yes, that's my intention.