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From:   Doug Anderson <dianders@chromium.org>
Date:   Tue, 15 Dec 2020 07:42:37 -0800
Message-ID: <CAD=FV=U0cVz6XgFnctGHcu1sNABAJsnBy8PPYjOSO5wKQGR7RQ@mail.gmail.com>
Subject: Re: [PATCH] arm64: dts: qcom: sc7180: Enable passive polling for cpu
 thermal zones
To:     Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>
Cc:     Andy Gross <agross@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Amit Kucheria <amit.kucheria@verdurent.com>,
        Matthias Kaehlcke <mka@chromium.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>
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Hi,

On Tue, Dec 15, 2020 at 1:39 AM Manaf Meethalavalappu Pallikunhi
<manafm@codeaurora.org> wrote:
>
> Enable passive polling delay for cpu thermal zone for sc7180. It
> enables periodic thermal zone re-evaluation on post first trip
> temperature violation.
>
> Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>
> ---
>  arch/arm64/boot/dts/qcom/sc7180.dtsi | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> index 98050b3..79d0747 100644
> --- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> @@ -4355,7 +4355,7 @@
>
>         thermal-zones {
>                 cpu0-thermal {
> -                       polling-delay-passive = <0>;
> +                       polling-delay-passive = <50>;

Matthias already landed a similar patch, see:

https://lore.kernel.org/r/20201111120334.1.Ifc04ea235c3c370e3b21ec3b4d5dead83cc403b4@changeid

I guess the question is whether 50 is better or 250 is better.  Is
this just a finger in the wind estimate or do you have data showing
that 50 is better than 250?

-Doug