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From:   Jun Li <lijun.kernel@gmail.com>
Date:   Fri, 21 Feb 2020 09:59:38 +0800
Message-ID: <CAKgpwJXVo_Psyu45+KfRKsTRBc6LRWSvUw2CWdUQseAoKd2p9g@mail.gmail.com>
Subject: Re: [PATCH v3 2/3] usb: dwc3: gadget: Add support for disabling SS
 instances in park mode
To:     Neil Armstrong <narmstrong@baylibre.com>
Cc:     Felipe Balbi <balbi@kernel.org>, khilman@baylibre.com,
        linux-usb@vger.kernel.org, linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Dongjin Kim <tobetter@gmail.com>,
        Jianxin Pan <jianxin.pan@amlogic.com>,
        Thinh Nguyen <thinhn@synopsys.com>, Tim <elatllat@gmail.com>
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Neil Armstrong <narmstrong@baylibre.com> =E4=BA=8E2020=E5=B9=B42=E6=9C=8819=
=E6=97=A5=E5=91=A8=E4=B8=89 =E4=B8=8B=E5=8D=8810:18=E5=86=99=E9=81=93=EF=BC=
=9A
>
> In certain circumstances, the XHCI SuperSpeed instance in park mode
> can fail to recover, thus on Amlogic G12A/G12B/SM1 SoCs when there is hig=
h
> load on the single XHCI SuperSpeed instance, the controller can crash lik=
e:
>  xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint comm=
and.
>  xhci-hcd xhci-hcd.0.auto: Host halt failed, -110
>  xhci-hcd xhci-hcd.0.auto: xHCI host controller not responding, assume de=
ad
>  xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint comm=
and.
>  hub 2-1.1:1.0: hub_ext_port_status failed (err =3D -22)
>  xhci-hcd xhci-hcd.0.auto: HC died; cleaning up
>  usb 2-1.1-port1: cannot reset (err =3D -22)
>
> Setting the PARKMODE_DISABLE_SS bit in the DWC3_USB3_GUCTL1 mitigates
> the issue. The bit is described as :
> "When this bit is set to '1' all SS bus instances in park mode are disabl=
ed"
>
> Synopsys explains in [1]:
> The GUCTL1.PARKMODE_DISABLE_SS is only available in
> dwc_usb3 controller running in host mode.
> This should not be set for other IPs.
> This can be disabled by default based on IP, but I recommend to have a
> property to enable this feature for devices that need this.
>
> [1] https://lore.kernel.org/linux-usb/45212db9-e366-2669-5c0a-3c5bd06287f=
6@synopsys.com

This is not for gadget, patch title should be:

usb: dwc3: core: add support...

Li Jun