Re: [PATCH v2 00/12] arm64: dts: qcom: sc8280xp: PCIe fixes and GICv3 ITS enable

From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Johan Hovold <johan@kernel.org>
Cc: "Bjorn Helgaas" <helgaas@kernel.org>,
	"Johan Hovold" <johan+linaro@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Bjorn Andersson" <andersson@kernel.org>,
	"Konrad Dybcio" <konrad.dybcio@linaro.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 00/12] arm64: dts: qcom: sc8280xp: PCIe fixes and GICv3 ITS enable
Date: Fri, 1 Mar 2024 18:44:45 +0530	[thread overview]
Message-ID: <20240301131445.GA5414@thinkpad> (raw)
In-Reply-To: <ZeHOF4p1LlNDiLcy@hovoldconsulting.com>

On Fri, Mar 01, 2024 at 01:46:15PM +0100, Johan Hovold wrote:
> On Fri, Mar 01, 2024 at 05:54:06PM +0530, Manivannan Sadhasivam wrote:
> > On Thu, Feb 29, 2024 at 04:37:27PM +0100, Johan Hovold wrote:
> 
> > > I'm all for digging further into this issue with the help of Qualcomm,
> > > but I don't think that should block this series as that would leave the
> > > link errors that we hit since 6.7 in place and effectively prevent us
> > > from enabling the ITS in 6.9.
> > 
> > Sounds fair. I will report back, perhaps with a fix based on what I get to know.
> 
> Sounds good, thanks.
> 
> > But I think it is better to disable L0s in the SoC dtsi itself. That's not only
> > because there are patches to essentially disable L0s in 2 of the available
> > platforms making use of this Soc, but also you are enabling GIC ITS in the SoC
> > dtsi and that may affect sa8540p which is making use of this dtsi.
> 
> I did not do so on purpose as I'm only disabling L0s on machines where
> I've confirmed the issue. And the assumption for now is that this is a
> machine-level issue.
> 
> > The users of that SoC may have not noticed the errors as you did before, but
> > enabling GIC ITS will certainly make the issue visible to them (more likely).
> 
> Sure and that would be good to know as that would give us another data
> point which may help determine where the problem lies. Enabling the ITS
> will (hopefully) be done in 6.9 so we'll have a whole cycle to disable
> L0s where needed. I don't think this should be done before then.
> 

Ok. Let's see what happens :)

For the series:

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

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