linux-kernel - Re: [PATCH] arm64: dts: qcom: qrb2210-rb1: disable cluster power domains

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Message-ID: <20240111124439.GB3003@thinkpad>
Date: Thu, 11 Jan 2024 18:14:39 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-arm-msm@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm64: dts: qcom: qrb2210-rb1: disable cluster power
 domains

On Thu, Jan 11, 2024 at 08:02:32AM +0200, Dmitry Baryshkov wrote:
> On Thu, 11 Jan 2024 at 06:45, Manivannan Sadhasivam
> <manivannan.sadhasivam@...aro.org> wrote:
> >
> > On Thu, Jan 11, 2024 at 04:01:14AM +0200, Dmitry Baryshkov wrote:
> > > If cluster domain idle state is enabled on the RB1, the board becomes
> > > significantly less responsive. Under certain circumstances (if some of
> > > the devices are disabled in kernel config) the board can even lock up.
> > >
> > > It seems this is caused by the MPM not being pinged during CPU idle (in
> > > the same way the RPMh is pinged when cluster idle is entered).
> > >
> >
> > What does "ping" mean here? Please be more specific.
> 
> See rpmh_rsc_pd_callback(), rpmh_flush() and rpmh_rsc_write_next_wakeup().
> 
> RPMh driver (among other things) on entering the idle writes the next
> wake up time to the RPMh. The MPM driver in the vendor kernel does the
> same, see msm_mpm_timer_write() in msm-4.19
> 

Okay, thanks for the explanation. It'd be good if you have mentioned this in the
commit message as it is not obvious for one to understand what "ping" means.

- Mani

> >
> > - Mani
> >
> > > Disable cluster domain idle for the RB1 board until MPM driver is fixed
> > > to cooperate with the CPU idle states.
> > >
> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> > > ---
> > >  arch/arm64/boot/dts/qcom/qrb2210-rb1.dts | 18 ++++++++++++++++++
> > >  1 file changed, 18 insertions(+)
> > >
> > > diff --git a/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts b/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts
> > > index aa53b6af6d9c..9a0308ef8b0f 100644
> > > --- a/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts
> > > +++ b/arch/arm64/boot/dts/qcom/qrb2210-rb1.dts
> > > @@ -177,6 +177,24 @@ vph_pwr: regulator-vph-pwr {
> > >       };
> > >  };
> > >
> > > +&CPU_PD0 {
> > > +     /delete-property/ power-domains;
> > > +};
> > > +
> > > +&CPU_PD1 {
> > > +     /delete-property/ power-domains;
> > > +};
> > > +
> > > +&CPU_PD2 {
> > > +     /delete-property/ power-domains;
> > > +};
> > > +
> > > +&CPU_PD3 {
> > > +     /delete-property/ power-domains;
> > > +};
> > > +
> > > +/delete-node/ &CLUSTER_PD;
> > > +
> > >  &gpi_dma0 {
> > >       status = "okay";
> > >  };
> > >
> > > ---
> > > base-commit: 39676dfe52331dba909c617f213fdb21015c8d10
> > > change-id: 20240111-qrb2210-rb1-no-cluster-idle-7bf43b3a0452
> > >
> > > Best regards,
> > > --
> > > Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> > >
> > >
> >
> > --
> > மணிவண்ணன் சதாசிவம்
> 
> 
> 
> -- 
> With best wishes
> Dmitry

-- 
மணிவண்ணன் சதாசிவம்