linux-kernel - Re: [PATCH v2 1/2] powerpc: Add helpers for LPCR PECE1 operations

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Date:	Fri, 23 Jan 2015 15:20:21 +1100
From:	Michael Ellerman <mpe@...erman.id.au>
To:	Shreyas B Prabhu <shreyas@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v2 1/2] powerpc: Add helpers for LPCR PECE1 operations

On Fri, 2015-01-23 at 09:16 +0530, Shreyas B Prabhu wrote:
> 
> On Friday 23 January 2015 08:36 AM, Michael Ellerman wrote:
> > On Mon, 2015-01-19 at 13:35 +0530, Shreyas B. Prabhu wrote:
> >> PECE1 bit in LPCR is used to control whether decrementer can cause exit
> >> from powersaving states. PECE1 bit is cleared before entering fastsleep
> >> or deeper powersaving state and it is set on waking up. Since both
> >> cpuidle and cpu offline operations use these powersaving states, add
> >> helper functions to be used in both these places.
> > 
> > Thanks.
> > 
> > That isn't really much clearer than the original, so in the end I just merged
> > your original fix.
> > 
> > I'll think if there's a bigger consolidation we can do that makes it clearer.
>
> Helper could have been this :
> 
> #define   LPCR_CLEAR_PECE1	(mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1)
> 
> This perhaps would make it more clearer, but it will end up using additional mfspr here-
 
Yeah.

Maybe we just leave it open coded, I'll have a think about it.

cheers


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