linux-kernel - Re: [PATCH v2 1/5] thermal: change "hysteresis" as optional property

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: <20160308135743.GC4921@leoy-linaro>
Date:	Tue, 8 Mar 2016 21:57:43 +0800
From:	Leo Yan <leo.yan@...aro.org>
To:	Javi Merino <javi.merino@....com>
Cc:	Eduardo Valentin <edubezval@...il.com>,
	Wei Xu <xuwei5@...ilicon.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>,
	Zhang Rui <rui.zhang@...el.com>,
	kongxinwei <kong.kongxinwei@...ilicon.com>,
	Punit Agrawal <Punit.Agrawal@....com>,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 1/5] thermal: change "hysteresis" as optional property

Hi Eduardo,

On Fri, Mar 04, 2016 at 11:57:53AM +0000, Javi Merino wrote:
> On Fri, Mar 04, 2016 at 11:03:49AM +0800, Leo Yan wrote:
> > On Thu, Mar 03, 2016 at 08:29:44AM -0800, Eduardo Valentin wrote:
> > > On Fri, Feb 26, 2016 at 11:43:43AM +0800, Leo Yan wrote:

[...]

> > > > The property "hysteresis" is mandatory for trip points, so if without
> > > > it the thermal zone cannot register successfully. But "hysteresis" is
> > > > ignored in the thermal subsystem and only inquired by several thermal
> > > > sensor drivers.
> > > 
> > > If the Linux thermal subsystem has a problem with handling hysteresis, I
> > > would rather fix Linux code than relaxing the DT binding. Or if you
> > > still believe hysteresis is really optional, I would prefer to see a
> > > better justification than "Linux ignores it".
> 
> I see it the other way round, Is hysteresis a property that, without
> it, the thermal code can't configure itself so it fails to create the
> trip point?  The current code goes "There is no hysteresis for this
> property, I don't know how to set up this trip point!".  I think we
> can do better than this.

Do you agree with Javi's suggestion? If you think it's okay, I will
move on to send out a new version patch based on Javi's comments.

Thanks,
Leo Yan