tree a2079deddd3e5066f22dfc166f297a2da9636432
parent 7fd94beecaff19b346efbf6b77288ab4b0b42dbd
author Alan Stern <stern@rowland.harvard.edu> 1352302290 -0500
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1352686008 -0800

USB: fix endpoint-disabling for failed config changes

This patch (as1631) fixes a bug that shows up when a config change
fails for a device under an xHCI controller.  The controller needs to
be told to disable the endpoints that have been enabled for the new
config.  The existing code does this, but before storing the
information about which endpoints were enabled!  As a result, any
second attempt to install the new config is doomed to fail because
xhci-hcd will refuse to enable an endpoint that is already enabled.

The patch optimistically initializes the new endpoints' device
structures before asking the device to switch to the new config.  If
the request fails then the endpoint information is already stored, so
we can use usb_hcd_alloc_bandwidth() to disable the endpoints with no
trouble.  The rest of the error path is slightly more complex now; we
have to disable the new interfaces and call put_device() rather than
simply deallocating them.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Matthias Schniedermeyer <ms@citd.de>
CC: Sarah Sharp <sarah.a.sharp@linux.intel.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>