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Subject: Re: [PATCH v3] xhci: Add quirk to workaround the errata seen on
 Cavium Thunder-X2 Soc
To:     "Cherian, George" <George.Cherian@cavium.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Cc:     "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "stern@rowland.harvard.edu" <stern@rowland.harvard.edu>
References: <1540896507-23876-1-git-send-email-george.cherian@cavium.com>
From:   Mathias Nyman <mathias.nyman@intel.com>
Message-ID: <d450f63d-b1ed-afe2-4bde-4d1aa246d079@intel.com>
Date:   Tue, 30 Oct 2018 13:26:41 +0200
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On 30.10.2018 12:48, 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 device may come up as USB 1
> if a connection to a USB 1 device is followed by another connection to
> a USB 2 device, the link will come up as USB 1 for the USB 2 device.
> 
> Resolution: Reset the PHY after the USB 1 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().
> 
> Signed-off-by: George Cherian <george.cherian@cavium.com>

Thanks, adding to queue

-Mathias