linux-kernel - Re: [PATCH v3 4/5] cpufreq: apple-soc: Add new driver to control Apple SoC CPU P-states

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]

Date:   Mon, 14 Nov 2022 12:33:23 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Hector Martin <marcan@...can.st>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Sven Peter <sven@...npeter.dev>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Marc Zyngier <maz@...nel.org>,
        Mark Kettenis <mark.kettenis@...all.nl>, asahi@...ts.linux.dev,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 4/5] cpufreq: apple-soc: Add new driver to control
 Apple SoC CPU P-states

On 14-11-22, 15:57, Hector Martin wrote:
> I don't think you understood me. We have multiple identical clusters.
> All those clusters share an OPP table but are *not* the same cpufreq
> domain. So we can have 8 CPUs which are two 4-CPU cluster using one OPP
> table.

I looked at the patch 5/5. It shows two clusters, e and p, with four CPUs in
each cluster. And as per the OPP table all the CPUs in cluster e are part of
same frequency domain, i.e. switch rate together. Same with all CPUs of cluster
p.

And I also see both the clusters have separate OPP tables.

> There is no way to express this relationship with OPP tables without
> duplicating the tables themselves.

Can you show how the DT looks in this case ? I am still not clear on what the
scenario is here :(

-- 
viresh