BMCR_SPEED1000
ctl &= ~(BMCR_SPEED100 | BMCR_SPEED1000 | BMCR_ANENABLE);
ctl |= BMCR_SPEED1000;
if (ctl & BMCR_SPEED1000) /* auto-negotiation required for GigE */
if (bmcr & BMCR_SPEED1000)