linux-kernel - Re: [PATCH V2 2/2] base/drivers/arch_topology: Default dmips-mhz if they are not set in DT

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Date:   Fri, 23 Nov 2018 11:32:24 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     rjw@...ysocki.net, linux-kernel@...r.kernel.org,
        Chris Redpath <chris.redpath@...aro.org>,
        Quentin Perret <quentin.perret@...aro.org>,
        Amit Kucheria <amit.kucheria@...aro.org>,
        Nicolas Dechesne <nicolas.dechesne@...aro.org>,
        Niklas Cassel <niklas.cassel@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH V2 2/2] base/drivers/arch_topology: Default dmips-mhz if
 they are not set in DT

On 23/11/2018 11:04, Viresh Kumar wrote:
> On 22-11-18, 13:36, Daniel Lezcano wrote:
>> In the case of asymmetric SoC with the same micro-architecture, we
>> have a group of CPUs with smaller OPPs than the other group. One
>> example is the 96boards dragonboard 820c. There is no dmips/MHz
>> difference between both groups, so no need to specify the values in
>> the DT. Unfortunately, without these defined, there is no scaling
>> capacity computation triggered, so we need to write
>> 'capacity-dmips-mhz' for each CPU with the same value in order to
>> force the scaled capacity computation.
>>
>> Fix this by setting a default capacity to SCHED_CAPACITY_SCALE, if no
>> 'capacity-dmips-mhz' is defined in the DT.
> 
> We aren't doing this anymore. You should rather explain that we just
> allocate raw_capacity now and rest is left for
> init_cpu_capacity_callback() to fix.

What about?

"In the case of asymmetric SoC with the same micro-architecture, we
have a group of CPUs with smaller OPPs than the other group. One
example is the 96boards dragonboard 820c. There is no dmips/MHz
difference between both groups, so no need to specify the values in
the DT. Unfortunately, without these defined, there is no scaling
capacity computation triggered, so we need to write
'capacity-dmips-mhz' for each CPU with the same value in order to
force the scaled capacity computation.

In order to fix this situation, allocate 'raw_capacity' so the pointer
is set and the init_cpu_capacity_callback() function can be called."

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