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From: Michael Ellerman <mpe@ellerman.id.au>
To: Stewart Smith <stewart@linux.vnet.ibm.com>,
        Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
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Subject: Re: [PATCH v8 05/10] powerpc/perf: IMC pmu cpumask and cpuhotplug support
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Date: Fri, 12 May 2017 13:33:32 +1000
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Stewart Smith <stewart@linux.vnet.ibm.com> writes:

> Madhavan Srinivasan <maddy@linux.vnet.ibm.com> writes:
>>>      * in patch 9 should opal_imc_counters_init return something other
>>>        than OPAL_SUCCESS in the case on invalid arguments? Maybe
>>>        OPAL_PARAMETER? (I think you fix this in a later patch anyway?)
>>
>> So, init call will return OPAL_PARAMETER for the unsupported
>> domains (core and nest are supported). And if the init operation
>> fails for any reason, it would return OPAL_HARDWARE. And this is
>> documented.
>
> (I'll comment on the skiboot one too), but I think that if the class
> exists but init is a no-op, then OPAL_IMC_COUNTERS_INIT should return
> OPAL_SUCCESS and just do nothing. This future proofs everything, and the
> API is that one *must* call _INIT before start.

Yes, 100%.

That's what I described in my replies to a previous version, if it
doesn't do that we need to fix it.

cheers