Messages in this thread | | | From | Michael Kao (高振翔) <> | Subject | RE: [PATCH v2 1/8] arm64: dts: mt8183: add thermal zone node | Date | Fri, 6 Dec 2019 09:46:38 +0000 |
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-----Original Message----- From: Matthias Kaehlcke [mailto:mka@chromium.org] Sent: Friday, May 31, 2019 12:08 AM To: Hsin-Yi Wang <hsinyi@chromium.org> Cc: Michael Kao (高振翔) <Michael.Kao@mediatek.com>; Zhang Rui <rui.zhang@intel.com>; Eduardo Valentin <edubezval@gmail.com>; Daniel Lezcano <daniel.lezcano@linaro.org>; Rob Herring <robh+dt@kernel.org>; Mark Rutland <mark.rutland@arm.com>; Matthias Brugger <matthias.bgg@gmail.com>; linux-pm@vger.kernel.org; devicetree@vger.kernel.org; lkml <linux-kernel@vger.kernel.org>; moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE <linux-arm-kernel@lists.infradead.org>; linux-mediatek@lists.infradead.org Subject: Re: [PATCH v2 1/8] arm64: dts: mt8183: add thermal zone node
On Thu, May 30, 2019 at 02:27:28PM +0800, Hsin-Yi Wang wrote: > On Fri, May 10, 2019 at 9:27 PM michael.kao <michael.kao@mediatek.com> wrote: > > > + > > + tzts1: tzts1 { > > + polling-delay-passive = <0>; > > + polling-delay = <0>; > > + thermal-sensors = <&thermal 1>; > > + sustainable-power = <0>; > > + trips {}; > > + cooling-maps {}; > > + }; > > + > Is 0 a valid initial sustainable-power setting? Since we'll still get > warning[1] about this, though it might not be harmful. > > If 0 is a valid setting, maybe we should consider showing the warning > of not setting this property in [2]? > > [1] > https://elixir.bootlin.com/linux/latest/source/drivers/thermal/power_a > llocator.c#L570 [2] > https://elixir.bootlin.com/linux/latest/source/drivers/thermal/of-ther > mal.c#L1049
IIUC a value of 0 is pointless, the thermal framework will still use an estimated value:
https://elixir.bootlin.com/linux/v5.1.5/source/drivers/thermal/power_allocator.c#L203
As commented on v1 (https://patchwork.kernel.org/patch/10926519/#22620905) the value of the property may depend on the thermal characteristics of the device, there is not one correct value per SoC/core. If it is specified at SoC level device makers should be aware that they might have to override it for 'optimal' behavior on their device.
I think there is no need to set sustainable-power for tzts1~6. They don't bind thermal instance and will not thermal throttle. So it will be also zero if we don't set sustainable-power and let it use estimate value. For the purpose of preventing warning, I think I can set sustainable-power of tzts1~6 the same to cpu_thermal.
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