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Date: Tue, 4 Jun 2024 12:46:54 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Krishna Kurapati PSSNV <quic_kriskura@quicinc.com>
Cc: cros-qcom-dts-watchers@chromium.org, 
	Krzysztof Kozlowski <krzk+dt@kernel.org>, Rob Herring <robh@kernel.org>, 
	Bjorn Andersson <andersson@kernel.org>, Konrad Dybcio <konrad.dybcio@linaro.org>, 
	Conor Dooley <conor+dt@kernel.org>, Stephen Boyd <swboyd@chromium.org>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Matthias Kaehlcke <mka@chromium.org>, 
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, 
	quic_ppratap@quicinc.com, quic_jackp@quicinc.com, Doug Anderson <dianders@google.com>, 
	stable@vger.kernel.org
Subject: Re: [PATCH v2 1/2] arm64: dts: qcom: sc7180: Disable SuperSpeed
 instances in park mode
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On Tue, Jun 04, 2024 at 01:34:44PM +0530, Krishna Kurapati PSSNV wrote:
> 
> 
> On 6/4/2024 1:16 PM, Dmitry Baryshkov wrote:
> > On Tue, Jun 04, 2024 at 11:36:58AM +0530, Krishna Kurapati wrote:
> > > On SC7180, in host mode, it is observed that stressing out controller
> > > results in HC died error:
> > > 
> > >   xhci-hcd.12.auto: xHCI host not responding to stop endpoint command
> > >   xhci-hcd.12.auto: xHCI host controller not responding, assume dead
> > >   xhci-hcd.12.auto: HC died; cleaning up
> > > 
> > > And at this instant only restarting the host mode fixes it. Disable
> > > SuperSpeed instances in park mode for SC7180 to mitigate this issue.
> > 
> > Let me please repeat the question from v1:
> > 
> > Just out of curiosity, what is the park mode?
> > 
> 
> Sorry, Missed the mail in v1.
> 
> Databook doesn't give much info on this bit (SS case, commit 7ba6b09fda5e0)
> but it does in HS case (commit d21a797a3eeb2).
> 
> From the mail we received from Synopsys, they described it as follows:
> 
> "Park mode feature allows better throughput on the USB in cases where a
> single EP is active. It increases the degree of pipelining within the
> controller as long as a single EP is active."

Thank you!

> 
> Even in the current debug for this test case, Synopsys suggested us to set
> this bit to avoid the controller being dead and we are waiting for further
> answers from them.

Should these quirks be enabled for other Qualcomm platforms? If so,
which platforms should get it?

> I can update thread with more info once we get some data from Synopsys.
> 
> Regards,
> Krishna,
> 
> > > 
> > > Reported-by: Doug Anderson <dianders@google.com>
> > > Cc: <stable@vger.kernel.org>
> > > Fixes: 0b766e7fe5a2 ("arm64: dts: qcom: sc7180: Add USB related nodes")
> > > Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> > > ---
> > > Removed RB/TB tag from Doug as commit text was updated.
> > > 
> > >   arch/arm64/boot/dts/qcom/sc7180.dtsi | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> > > index 2b481e20ae38..cc93b5675d5d 100644
> > > --- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
> > > +++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
> > > @@ -3063,6 +3063,7 @@ usb_1_dwc3: usb@a600000 {
> > >   				iommus = <&apps_smmu 0x540 0>;
> > >   				snps,dis_u2_susphy_quirk;
> > >   				snps,dis_enblslpm_quirk;
> > > +				snps,parkmode-disable-ss-quirk;
> > >   				phys = <&usb_1_hsphy>, <&usb_1_qmpphy QMP_USB43DP_USB3_PHY>;
> > >   				phy-names = "usb2-phy", "usb3-phy";
> > >   				maximum-speed = "super-speed";
> > > -- 
> > > 2.34.1
> > > 
> > 

-- 
With best wishes
Dmitry