linux-kernel - Re: [PATCH 3/7] arm64: dts: qcom: sm8550: Fix up CPU idle states

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Message-ID: <6bcb460b-6deb-4918-9058-67536e0af0ad@linaro.org>
Date:   Wed, 30 Aug 2023 22:35:29 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Abel Vesa <abel.vesa@...aro.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Sai Prakash Ranjan <quic_saipraka@...cinc.com>,
        Vinod Koul <vkoul@...nel.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org
Subject: Re: [PATCH 3/7] arm64: dts: qcom: sm8550: Fix up CPU idle states

On 30.08.2023 22:13, Dmitry Baryshkov wrote:
> On Wed, 30 Aug 2023 at 22:04, Konrad Dybcio <konrad.dybcio@...aro.org> wrote:
>>
>> The idle residency times are largely too low according to the vendor
>> kernel (maybe they came from an earlier release or something), especially
>> for the prime X2 core. Fix them.
>>
>> Fixes: ffc50b2d3828 ("arm64: dts: qcom: Add base SM8550 dtsi")
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---
>>  arch/arm64/boot/dts/qcom/sm8550.dtsi | 32 +++++++++++++++++++++-----------
>>  1 file changed, 21 insertions(+), 11 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/sm8550.dtsi b/arch/arm64/boot/dts/qcom/sm8550.dtsi
>> index d115960bdeec..c21ba6afa752 100644
>> --- a/arch/arm64/boot/dts/qcom/sm8550.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/sm8550.dtsi
>> @@ -283,9 +283,9 @@ LITTLE_CPU_SLEEP_0: cpu-sleep-0-0 {
>>                                 compatible = "arm,idle-state";
>>                                 idle-state-name = "silver-rail-power-collapse";
>>                                 arm,psci-suspend-param = <0x40000004>;
>> -                               entry-latency-us = <800>;
>> +                               entry-latency-us = <550>;
>>                                 exit-latency-us = <750>;
>> -                               min-residency-us = <4090>;
>> +                               min-residency-us = <6700>;
>>                                 local-timer-stop;
>>                         };
>>
>> @@ -294,8 +294,18 @@ BIG_CPU_SLEEP_0: cpu-sleep-1-0 {
>>                                 idle-state-name = "gold-rail-power-collapse";
>>                                 arm,psci-suspend-param = <0x40000004>;
>>                                 entry-latency-us = <600>;
>> -                               exit-latency-us = <1550>;
>> -                               min-residency-us = <4791>;
>> +                               exit-latency-us = <1300>;
>> +                               min-residency-us = <8136>;
>> +                               local-timer-stop;
>> +                       };
>> +
>> +                       PRIME_CPU_SLEEP_0: cpu-sleep-2-0 {
>> +                               compatible = "arm,idle-state";
>> +                               idle-state-name = "gold-plus-rail-power-collapse";
>> +                               arm,psci-suspend-param = <0x40000004>;
>> +                               entry-latency-us = <500>;
>> +                               exit-latency-us = <1350>;
>> +                               min-residency-us = <7480>;
>>                                 local-timer-stop;
> 
> This isn't only fixing the time properties, but also adds the whole
> new sleep state!
It does add a "new" sleep state with the exact same parameters,
the only thing being that it's exclusive to the prime core and
the only thing that differs is the residencies.

Konrad