linux-kernel - Re: [PATCH] arm64: dts: qcom: qrb5165-rb5: Disable cpuidle states

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Message-ID: <CAPDyKFo=w-ET62c-B6=qSpkZm-V9LmBuVRy38GzX_UAjQhX6oA@mail.gmail.com>
Date:   Thu, 20 Oct 2022 16:40:15 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Sudeep Holla <sudeep.holla@....com>,
        Amit Pundir <amit.pundir@...aro.org>
Cc:     Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Maulik Shah <quic_mkshah@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        dt <devicetree@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arm64: dts: qcom: qrb5165-rb5: Disable cpuidle states

On Thu, 20 Oct 2022 at 16:09, Amit Pundir <amit.pundir@...aro.org> wrote:
>
> On Thu, 20 Oct 2022 at 15:01, Sudeep Holla <sudeep.holla@....com> wrote:
> >
> > On Wed, Oct 19, 2022 at 01:57:34PM +0200, Ulf Hansson wrote:
> > > On Tue, 18 Oct 2022 at 16:53, Amit Pundir <amit.pundir@...aro.org> wrote:
> > > >
> > > > Disable cpuidle states for RB5. These cpuidle states
> > > > made the device highly unstable and it runs into the
> > > > following crash frequently:
> > > >
> > > > [    T1] vreg_l11c_3p3: failed to enable: -ETIMEDOUT
> > > > [    T1] qcom-rpmh-regulator 18200000.rsc:pm8150l-rpmh-regulators: ldo11: devm_regulator_register() failed, ret=-110
> > > > [    T1] qcom-rpmh-regulator: probe of 18200000.rsc:pm8150l-rpmh-regulators failed with error -110
> > > >
> > > > Fixes: 32bc936d7321 ("arm64: dts: qcom: sm8250: Add cpuidle states")
> > > > Signed-off-by: Amit Pundir <amit.pundir@...aro.org>
> > > > ---
> > > >  arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 8 ++++++++
> > > >  1 file changed, 8 insertions(+)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts b/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts
> > > > index cc003535a3c5..f936c41bfbea 100644
> > > > --- a/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts
> > > > +++ b/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts
> > > > @@ -251,6 +251,14 @@ qca639x: qca639x {
> > > >
> > > >  };
> > > >
> > > > +&LITTLE_CPU_SLEEP_0 {
> > > > +       status = "disabled";
> > > > +};
> > > > +
> > > > +&BIG_CPU_SLEEP_0 {
> > > > +       status = "disabled";
> > > > +};
> > > > +
> > > >  &adsp {
> > > >         status = "okay";
> > > >         firmware-name = "qcom/sm8250/adsp.mbn";
> > > > --
> > > > 2.25.1
> > >
> > > Disabling the CPU idlestates, will revert us back to using only the WFI state.
> > >
> > > An option that probably works too is to just drop the idlestate for
> > > the CPU cluster. Would you mind trying the below and see if that works
> > > too?
> > >
> >
> > Indeed this is was I suggested to check initially. But I was surprised to
> > see IIUC, Amit just disabled CPU states with above change and got it working.
> > So it is not cluster state alone causing the issue, is it somehow presence
> > of both cpu and cluster states ? Am I missing something here.
> >
> > > diff --git a/arch/arm64/boot/dts/qcom/sm8250.dtsi
> > > b/arch/arm64/boot/dts/qcom/sm8250.dtsi
> > > index c32227ea40f9..c707a49e8001 100644
> > > --- a/arch/arm64/boot/dts/qcom/sm8250.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/sm8250.dtsi
> > > @@ -700,7 +700,6 @@ CPU_PD7: cpu7 {
> > >
> > >                 CLUSTER_PD: cpu-cluster0 {
> > >                         #power-domain-cells = <0>;
> > > -                       domain-idle-states = <&CLUSTER_SLEEP_0>;
> >
> > How about just marking CLUSTER_SLEEP_0 state disabled ? That looks cleaner
> > than deleting this domain-idle-states property here. Also not sure if DTS
> > warnings will appear if you delete this ?
>
> Hi, I did try disabling CLUSTER_SLEEP_0: cluster-sleep-0 {} in
> domain-idle-states {} but that didn't help. That's why I end up
> disabling individual cpu states in idle-states {}.

Yep, this boils down to the fact that genpd doesn't check whether the
domain-idle-state is disabled by using of_device_is_available(). See
genpd_iterate_idle_states().

That said, I suggest we go with the above one-line change. It may not
be as clean as it could be, but certainly easy to revert when the
support for it has been added in a newer kernel.

Amit, do you want me to post a new patch or do you prefer to re-spin
your patch? It doesn't matter to me.

Kind regards
Uffe