tree b70b68e35d8a9e7264263848ce48a9863b387c55
parent 6219c047d3fe18dee4916d6898fc94f5a7ffd156
author Sarah Sharp <sarah.a.sharp@linux.intel.com> 1260403153 -0800
committer Greg Kroah-Hartman <gregkh@suse.de> 1267570392 -0800

USB: xhci: Notify the xHC when a device is reset.

When a USB device is reset, the xHCI hardware must know, in order to match
the device state and disable all endpoints except control endpoint 0.
Issue a Reset Device command after a USB device is successfully reset.
Wait on the command to finish, and then cache or free the disabled
endpoint rings.

There are four different USB device states that the xHCI hardware tracks:
 - disabled/enabled - device connection has just been detected,
 - default - the device has been reset and has an address of 0,
 - addressed - the device has a non-zero address but no configuration has
   been set,
 - configured - a set configuration succeeded.

The USB core may issue a port reset when a device is in any state, but the
Reset Device command will fail for a 0.96 xHC if the device is not in the
addressed or configured state.  Don't consider this failure as an error,
but don't free any endpoint rings if this command fails.

A storage driver may request that the USB device be reset during error
handling, so use GPF_NOIO instead of GPF_KERNEL while allocating memory
for the Reset Device command.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>