linux-kernel - Re: [PATCH V3 2/2] base/drivers/arch_topology: Default dmips-mhz if they are not set in DT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20181126084533.f5kydkdhukjez2kg@vireshk-i7>
Date:   Mon, 26 Nov 2018 14:15:33 +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 V3 2/2] base/drivers/arch_topology: Default dmips-mhz if
 they are not set in DT

On 26-11-18, 09:44, 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.
> 
> In order to fix this situation, allocate 'raw_capacity' so the pointer
> is set and the init_cpu_capacity_callback() function can be called.
> 
> This was tested on db820c:
>  - specified values in the DT (correct results)
>  - partial values defined in the DT (error + fallback to defaults)
>  - no specified values in the DT (correct results)
> 
> correct results are:
>   cat /sys/devices/system/cpu/cpu*/cpu_capacity
>    758
>    758
>   1024
>   1024
> 
>   ... respectively for CPU0, CPU1, CPU2 and CPU3.
> 
> That reflects the capacity for the max frequencies 1593600 and 2150400.
> 
> Cc: Chris Redpath <chris.redpath@...aro.org>
> Cc: Quentin Perret <quentin.perret@...aro.org>
> Cc: Viresh Kumar <viresh.kumar@...aro.org>
> Cc: Amit Kucheria <amit.kucheria@...aro.org>
> Cc: Nicolas Dechesne <nicolas.dechesne@...aro.org>
> Cc: Niklas Cassel <niklas.cassel@...aro.org>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> ---
>  drivers/base/arch_topology.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)

Reviewed-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh