Messages in this thread | | | Date | Sat, 2 Jun 2018 01:14:18 -0700 | From | Olof Johansson <> | Subject | Re: [PATCH 1/6] arm64: dts: amlogic: Add missing cooling device properties for CPUs |
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On Mon, May 28, 2018 at 04:43:58PM +0530, Viresh Kumar wrote: > On 25-05-18, 14:10, 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. > > Well, we don't allow that property to be present in /cpus node right > now and it is per device. And then we may not want all the CPUs to be > cooling devices really.
And what I am saying is that it sounds like a broken binding if you don't allow that, especially since it'll be a super common case that all CPUs will specify the same cooling-device specifier.
> > 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? > > This property is required to declare a device as a cooling-device and > the device here is CPU. We use it as a cooling device by limiting its > higher range of frequencies, so that it doesn't generate too much > heat. > > It is already there for CPU0 and CPU4, but it should really be there > for all the CPUs, like we have clock, supply, caches, etc.
You have #cooling-cells in the cpu node, but the actual data is in the thermal-zones nodes. Why isn't #cooling-cells under thermal-zones, next to cooling-maps?
-Olof
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