linux-kernel - Re: [PATCH 2/2] cpufreq: powernv: Use PMSR to verify global and local pstate

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Message-Id: <ce785008-f387-3e3f-243d-5d701fafc572@linux.vnet.ibm.com>
Date:   Mon, 7 Nov 2016 13:02:10 +0530
From:   Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linuxppc-dev@...ts.ozlabs.org, rjw@...ysocki.net,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/2] cpufreq: powernv: Use PMSR to verify global and local
 pstate

Thanks Viresh for taking a look at it.

I will make the mentioned changes in the next version of the patch and
will add Shilpa and Gautham to the mail chain.

Regards

Akshay Adiga


On 11/04/2016 12:11 PM, Viresh Kumar wrote:
> On 04-11-16, 10:57, Akshay Adiga wrote:
>> As fast_switch may get called in interrupt disable mode, it does not
> s/in interrupt disable mode/with interrupts disabled
> s/it does/it may
>
>> update the global_pstate_info data structure. Hence the global_pstate_info
>> has stale data whenever pstate is updated through fast_swtich().
> s/has/may have
> s/swtich/switch
>
>> So the gpstate_timer can fire after a fast_switch() call has update
> s/So the/The
> s/a fast_swtich() call has update/the fast_switch() call has updated
>
>> the pstates to a different value. Hence the timer handler cannot rely
>> on the cached values of local and global pstate and needs to read it
>> from the PMSR.
>>
>> Signed-off-by: Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>
>>
>> ---
>>   drivers/cpufreq/powernv-cpufreq.c | 32 ++++++++++++++++++++++----------
>>   1 file changed, 22 insertions(+), 10 deletions(-)
> I am not the best guy to judge the code changes here. Can you please include
> Shilpa and Gautham to the mail chain and get there feedback.
>
>
>