Re: [PATCH v3] xhci: Add quirk to workaround the errata seen on Cavium Thunder-X2 Soc

From: Mathias Nyman
Date: Tue Oct 30 2018 - 07:23:12 EST

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@xxxxxxxxxx>

Thanks, adding to queue