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From: narmstrong@baylibre.com (Neil Armstrong)
To: linus-amlogic@lists.infradead.org
Subject: [PATCH 1/6] arm64: dts: amlogic: Add missing cooling device properties for CPUs
Date: Sat, 26 May 2018 10:37:49 +0200	[thread overview]
Message-ID: <9f9cc086-6069-afbc-d3c6-46608ff35b79@baylibre.com> (raw)
In-Reply-To: <20180525211025.c73zdcdtyuvlewng@localhost>

Hi,

On 25/05/2018 23:10, Olof Johansson wrote:
> On Fri, May 25, 2018 at 11:10:01AM +0530, Viresh Kumar wrote:
>> The cooling device properties, like "#cooling-cells" and
>> "dynamic-power-coefficient", should either be present for all the CPUs
>> of a cluster or none. If these are present only for a subset of CPUs of
>> a cluster then things will start falling apart as soon as the CPUs are
>> brought online in a different order. For example, this will happen
>> because the operating system looks for such properties in the CPU node
>> it is trying to bring up, so that it can register a cooling device.
>>
>> Add such missing properties.
> 
> This seems awkward compared to just having one cooling-cells in the /cpus node
> instead.
> 
> What's it used for? I don't see any properties in the device nodes on meson-gxm
> that have any cooling-foo cells in them? So why should #cooling-cells be
> needed?


There is no reason to have the cooling-cells on these other CPUs, the DVFS is
controlled on the first CPU of each cluster, here cpu0 and cpu4 and only
cpu0 and cpu4 are used as cooling-cells.

Neil

> 
> 
> -Olof
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

  reply	other threads:[~2018-05-26  8:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-25  5:40 [PATCH 0/6] arm64: dts: " Viresh Kumar
2018-05-25  5:40 ` [PATCH 1/6] arm64: dts: amlogic: " Viresh Kumar
2018-05-25 21:10   ` Olof Johansson
2018-05-26  8:37     ` Neil Armstrong [this message]
2018-05-28 11:16       ` Viresh Kumar
2018-05-28 11:13     ` Viresh Kumar
2018-06-02  8:14       ` Olof Johansson
2018-06-05  4:37         ` Viresh Kumar

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