From b9cf95a7d1da0536905921fd50763beff63c6f52 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Thu, 20 Oct 2016 18:09:19 +0300
Subject: [PATCH] xhci: workaround for hosts missing CAS bit

commit 346e99736c3ce328fd42d678343b70243aca5f36 upstream.

If a device is unplugged and replugged during Sx system suspend
some  Intel xHC hosts will overwrite the CAS (Cold attach status) flag
and no device connection is noticed in resume.

A device in this state can be identified in resume if its link state
is in polling or compliance mode, and the current connect status is 0.
A device in this state needs to be warm reset.

Intel 100/c230 series PCH specification update Doc #332692-006 Errata #8

Observed on Cherryview and Apollolake as they go into compliance mode
if LFPS times out during polling, and re-plugged devices are not
discovered at resume.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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