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2f31a67f01
USB3 roothub might autosuspend before a plugged USB3 device is detected, causing USB3 device enumeration failure. USB3 devices don't show up as connected and enabled until USB3 link trainig completes. On a fast booting platform with a slow USB3 link training the link might reach the connected enabled state just as the bus is suspending. If this device is discovered first time by the xhci_bus_suspend() routine it will be put to U3 suspended state like the other ports which failed to suspend earlier. The hub thread will notice the connect change and resume the bus, moving the port back to U0 This U0 -> U3 -> U0 transition right after being connected seems to be too much for some devices, causing them to first go to SS.Inactive state, and finally end up stuck in a polling state with reset asserted Fix this by failing the bus suspend if a port has a connect change or is in a polling state in xhci_bus_suspend(). Don't do any port changes until all ports are checked, buffer all port changes and only write them in the end if suspend can proceed Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.