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8a3c9099a7
commit 2f31a67f01 upstream.
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>
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("hub_wq").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.