linux-kernel - Re: [PATCH v2 1/2] arm64: dts: qcom: sc7180: Disable SuperSpeed instances in park mode

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Date: Tue, 4 Jun 2024 15:27:47 +0530
From: Krishna Kurapati PSSNV <quic_kriskura@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
CC: <cros-qcom-dts-watchers@...omium.org>,
        Krzysztof Kozlowski
	<krzk+dt@...nel.org>,
        Rob Herring <robh@...nel.org>, Bjorn Andersson
	<andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        "Conor
 Dooley" <conor+dt@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        "Greg
 Kroah-Hartman" <gregkh@...uxfoundation.org>,
        Matthias Kaehlcke
	<mka@...omium.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <quic_ppratap@...cinc.com>, <quic_jackp@...cinc.com>,
        Doug Anderson
	<dianders@...gle.com>, <stable@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] arm64: dts: qcom: sc7180: Disable SuperSpeed
 instances in park mode



On 6/4/2024 3:16 PM, Dmitry Baryshkov wrote:
> 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?

In downstream we enable this for Gen-1 platforms. On v1 discussion 
thread, I agreed to send another series for other platforms.

I could've included it for others as well in this v2, but there are 
around 30 QC SoCs (or more) on upstream and many are very old. I need to 
go through all of them and figure out which ones are Gen-1. To not delay 
this for SC7280 and SC7180 (as chrome platforms need it right away), I 
sent v2 only for these two targets.

Regards,
Krishna,

> 
>> I can update thread with more info once we get some data from Synopsys.
>>
>> Regards,
>> Krishna,
>>
>>>>
>>>> Reported-by: Doug Anderson <dianders@...gle.com>
>>>> Cc: <stable@...r.kernel.org>
>>>> Fixes: 0b766e7fe5a2 ("arm64: dts: qcom: sc7180: Add USB related nodes")
>>>> Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.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@...0000 {
>>>>    				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
>>>>
>>>
>