Hi Alan, Thanks for the review. I will update the patch accordingly and send out v2. On 10/28/2018 10:48 PM, Alan Stern wrote: > > On Sat, 27 Oct 2018, Cherian, George wrote: > >> Implement workaround for ThunderX2 Errata-129 (documented in >> CN99XX Known Issues" available at Cavium support site). >> As per ThunderX2errata-129, USB-2.0 device may come up as USB-1.0 >> If a connection to a USB-1.0 device is followed by another connection >> to a USB-2.0 device, the link will come up as USB-1.0 for the USB-2.0 >> device. >> >> Resolution: Reset the PHY after the USB1.0 device is disconnected. >> The PHY reset sequence is done using private registers in XHCI register >> space. After the PHY is reset we check for the PLL lock status and retry >> the operation if it fails. From our tests, retrying 4 times is sufficient. >> >> Add a new quirk flag XHCI_RESET_PLL_ON_DISCONNECT to invoke the workaround >> in handle_xhci_port_status(). > > Minor nitpick (for both the patch description and the code comments): > > USB 1.0 was never widely adopted and is not used any more. The > earliest vesion of USB currently used in supported devices is USB 1.1. > Likewise, there are a few devices around that support USB 2.1, not > USB 2.0, but they are presumably also subject to the problem described > above. > > I suggest you change the description and the comments to refer to USB 1 > and USB 2 instead of USB 1.0 and USB 2.0, as the latter are too > restrictive and misleading. > > Alan Stern > Regards, -George
