Re: [PATCH v3 2/3] usb: dwc3: gadget: Add support for disabling SS instances in park mode

[Jun Li]

Neil Armstrong <narmstrong@xxxxxxxxxxxx> ä2020å2æ19æåä äå10:18åéï
>
> In certain circumstances, the XHCI SuperSpeed instance in park mode
> can fail to recover, thus on Amlogic G12A/G12B/SM1 SoCs when there is high
> load on the single XHCI SuperSpeed instance, the controller can crash like:
>  xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
>  xhci-hcd xhci-hcd.0.auto: Host halt failed, -110
>  xhci-hcd xhci-hcd.0.auto: xHCI host controller not responding, assume dead
>  xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
>  hub 2-1.1:1.0: hub_ext_port_status failed (err = -22)
>  xhci-hcd xhci-hcd.0.auto: HC died; cleaning up
>  usb 2-1.1-port1: cannot reset (err = -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 disabled"
>
> 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-3c5bd06287f6@xxxxxxxxxxxx

This is not for gadget, patch title should be:

usb: dwc3: core: add support...

Li Jun