USB: ohci handles hardware faults during root port resets

USB: ohci handles hardware faults during root port resets

I have found a problem where the root_port_reset() goes into an infinite
loop and stalls the kernel.

This happens when a hardware fault inside the machine occurs during a small
timing window.  In case of USB device connection, if a USB device responds to
hcd_submit_urb(), and later the controller fails before root_port_reset(),
root_port_reset() will loop infinitely because ohci_readl() will always
return "-1".  Such a failure can include ejecting a CardBus OHCI controller.

The probability of this problem is low, but it will increase if PnP type
usage is frequent.  The attached patch can solve this problem and I believe
that it is better to fix this problem.

Signed-off-by: Takamasa Ohtake <ohtake-txa@necst.nec.co.jp>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>