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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Message-ID: <20181126060142.skehankx7nzjpcdw@vireshk-i7>
Date:   Mon, 26 Nov 2018 11:31:42 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Daniel Lezcano <daniel.lezcano@...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 23-11-18, 11:32, Daniel Lezcano wrote:
> 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."

LGTM

-- 
viresh