Acking controller events on controllers that do not support
it can cause such controllers to lock up.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NJoe Handzik <joseph.t.handzik@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>