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Date: Tue, 30 Jan 2024 17:15:38 -0500
From: Lucas Karpinski <lkarpins@redhat.com>
To: Bjorn Andersson <andersson@kernel.org>
Cc: Andy Gross <agross@kernel.org>, 
	Konrad Dybcio <konrad.dybcio@linaro.org>, Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Re: [PATCH v2] arm64: dts: qcom: sa8540p-ride: disable pcie2a
 node
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> Why are there interrupt storms? What interrupt(s) is(are) involved?
In the earlier link that Andrew mentioned, the DesignWare PCIe driver
uses a chained interrupt to demultiplex the downstream MSI interrupts.
This meant we couldn't identify the MSI interrupt source, so it is not
clear what is causing the hw to misbehave the way that it is.
                                                   
> Do you consider this a temporary fix?            
This will likely be a permanent fix. Qualcomm disabled pcie2a in their 
downstream kernel as well, quite some time ago, so this may never be 
actually fixed.
                                                   
> Are you okay with pcie3a misbehaving?            
Yes, it would be great of the underlying issue was addressed, but at 
least the boards are usable with just pcie3a enabled and the nic will be 
available.      
                                                   
Lucas  

 
> > Signed-off-by: Lucas Karpinski <lkarpins@redhat.com>
> > ---
> > v2:
> > - don't remove the entire pcie2a node, just set status to disabled.
> > - update commit message.
> > 
> >  arch/arm64/boot/dts/qcom/sa8540p-ride.dts | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/arm64/boot/dts/qcom/sa8540p-ride.dts b/arch/arm64/boot/dts/qcom/sa8540p-ride.dts
> > index b04f72ec097c..177b9dad6ff7 100644
> > --- a/arch/arm64/boot/dts/qcom/sa8540p-ride.dts
> > +++ b/arch/arm64/boot/dts/qcom/sa8540p-ride.dts
> > @@ -376,14 +376,14 @@ &pcie2a {
> >  	pinctrl-names = "default";
> >  	pinctrl-0 = <&pcie2a_default>;
> >  
> > -	status = "okay";
> > +	status = "disabled";
> >  };
> >  
> >  &pcie2a_phy {
> >  	vdda-phy-supply = <&vreg_l11a>;
> >  	vdda-pll-supply = <&vreg_l3a>;
> >  
> > -	status = "okay";
> > +	status = "disabled";
> >  };
> >  
> >  &pcie3a {
> > -- 
> > 2.43.0
> > 
>