XM_IMSK
xm_write16(hw, port, XM_IMSK, XM_IMSK_DISABLE);
xm_write16(hw, port, XM_IMSK, XM_IMSK_DISABLE);
u16 msk = xm_read16(hw, port, XM_IMSK);
xm_write16(hw, port, XM_IMSK, msk);
msk = xm_read16(hw, port, XM_IMSK);
xm_write16(hw, port, XM_IMSK, msk);