linux-kernel - Re: [PATCH V3 2/7] PM / OPP: Introduce "domain-performance-state" binding to OPP nodes

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: <20170301061402.GE24323@vireshk-i7>
Date:   Wed, 1 Mar 2017 11:44:02 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rob Herring <robh@...nel.org>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        Rafael Wysocki <rjw@...ysocki.net>,
        Kevin Hilman <khilman@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        "linaro-kernel@...ts.linaro.org" <linaro-kernel@...ts.linaro.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Lina Iyer <lina.iyer@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH V3 2/7] PM / OPP: Introduce "domain-performance-state"
 binding to OPP nodes

On 28-02-17, 09:52, Rob Herring wrote:
> On Tue, Feb 28, 2017 at 9:14 AM, Ulf Hansson <ulf.hansson@...aro.org> wrote:
> > This comes from the early design of the generic PM domain, thus I
> > assume we have some HW with such complex PM topology. However, I don't
> > know if it is actually being used.
> >
> > Moreover, the corresponding DT bindings for "power-domains" parents,
> > can easily be extended to cover more than one parent. See more in
> > Documentation/devicetree/bindings/power/power_domain.txt
> 
> I could easily see device having 2 power domains. For example a cpu
> may have separate domains for RAM/caches and logic.

An important thing here is that PM domain doesn't support such devices. i.e. a
device isn't allowed to have multiple PM domains today. So a way to support such
devices can be to create a virtual PM domain, that has two parents and device as
its child.

-- 
viresh