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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Tue, 4 Jun 2024 13:05:34 +0300
Message-ID: <CAA8EJppS4+Kv+BTKxxUjEoo8H8XCoPBK-uhdTx6bGWgH6AvK6w@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] arm64: dts: qcom: sc7180: Disable SuperSpeed
 instances in park mode
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
Content-Type: text/plain; charset="UTF-8"

On Tue, 4 Jun 2024 at 12:58, Krishna Kurapati PSSNV
<quic_kriskura@quicinc.com> wrote:
>
>
>
> 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.

Ack, this is fine from my point of view. Thank you!

>
> Regards,
> Krishna,
>
> >
> >> I can update thread with more info once we get some data from Synopsys.


-- 
With best wishes
Dmitry