IMS_ENABLE_MASK
E1000_WRITE_REG(hw, E1000_IMS, IMS_ENABLE_MASK);
IMS_ENABLE_MASK & ~E1000_IMS_TXDW);
igb->ims_mask = IMS_ENABLE_MASK | E1000_IMS_TXQE;
igb->ims_mask = IMS_ENABLE_MASK | E1000_IMS_TXQE;
(IMS_ENABLE_MASK | E1000_IMS_TXQE));
igb->ims_mask = IMS_ENABLE_MASK;
E1000_WRITE_REG(hw, E1000_IMS, IMS_ENABLE_MASK);