/* hardware minimum and maximum for a single frame's data payload */
 #define TG3_MIN_MTU                    60
 #define TG3_MAX_MTU(tp)        \
-       (!(tp->tg3_flags2 & TG3_FLG2_5705_PLUS) ? 9000 : 1500)
+       ((tp->tg3_flags2 & TG3_FLG2_JUMBO_CAPABLE) ? 9000 : 1500)
 
 /* These numbers seem to be hard coded in the NIC firmware somehow.
  * You can't change the ring sizes, but you can change where you place
        if ((tp->phy_id & PHY_ID_MASK) == PHY_ID_BCM5401) {
                /* Cannot do read-modify-write on 5401 */
                tg3_writephy(tp, MII_TG3_AUX_CTRL, 0x4c20);
-       } else if (!(tp->tg3_flags2 & TG3_FLG2_5705_PLUS)) {
+       } else if (tp->tg3_flags2 & TG3_FLG2_JUMBO_CAPABLE) {
                u32 phy_reg;
 
                /* Set bit 14 with read-modify-write to preserve other bits */
        /* Set phy register 0x10 bit 0 to high fifo elasticity to support
         * jumbo frames transmission.
         */
-       if (!(tp->tg3_flags2 & TG3_FLG2_5705_PLUS)) {
+       if (tp->tg3_flags2 & TG3_FLG2_JUMBO_CAPABLE) {
                u32 phy_reg;
 
                if (!tg3_readphy(tp, MII_TG3_EXT_CTRL, &phy_reg))
        dev->mtu = new_mtu;
 
        if (new_mtu > ETH_DATA_LEN)
-               tp->tg3_flags |= TG3_FLAG_JUMBO_ENABLE;
+               tp->tg3_flags |= TG3_FLAG_JUMBO_RING_ENABLE;
        else
-               tp->tg3_flags &= ~TG3_FLAG_JUMBO_ENABLE;
+               tp->tg3_flags &= ~TG3_FLAG_JUMBO_RING_ENABLE;
 }
 
 static int tg3_change_mtu(struct net_device *dev, int new_mtu)
                               (i << RXD_OPAQUE_INDEX_SHIFT));
        }
 
-       if (tp->tg3_flags & TG3_FLAG_JUMBO_ENABLE) {
+       if (tp->tg3_flags & TG3_FLAG_JUMBO_RING_ENABLE) {
                for (i = 0; i < TG3_RX_JUMBO_RING_SIZE; i++) {
                        struct tg3_rx_buffer_desc *rxd;
 
                        break;
        }
 
-       if (tp->tg3_flags & TG3_FLAG_JUMBO_ENABLE) {
+       if (tp->tg3_flags & TG3_FLAG_JUMBO_RING_ENABLE) {
                for (i = 0; i < tp->rx_jumbo_pending; i++) {
                        if (tg3_alloc_rx_skb(tp, RXD_OPAQUE_RING_JUMBO,
                                             -1, i) < 0)
        }
 #endif
 
-       if (!(tp->tg3_flags & TG3_FLAG_JUMBO_ENABLE)) {
+       if (tp->dev->mtu <= ETH_DATA_LEN) {
                tw32(BUFMGR_MB_RDMA_LOW_WATER,
                     tp->bufmgr_config.mbuf_read_dma_low_water);
                tw32(BUFMGR_MB_MACRX_LOW_WATER,
                /* Setup replenish threshold. */
                tw32(RCVBDI_JUMBO_THRESH, tp->rx_jumbo_pending / 8);
 
-               if (tp->tg3_flags & TG3_FLAG_JUMBO_ENABLE) {
+               if (tp->tg3_flags & TG3_FLAG_JUMBO_RING_ENABLE) {
                        tw32(RCVDBDI_JUMBO_BD + TG3_BDINFO_HOST_ADDR + TG3_64BIT_REG_HIGH,
                             ((u64) tp->rx_jumbo_mapping >> 32));
                        tw32(RCVDBDI_JUMBO_BD + TG3_BDINFO_HOST_ADDR + TG3_64BIT_REG_LOW,
        tw32_rx_mbox(MAILBOX_RCV_STD_PROD_IDX + TG3_64BIT_REG_LOW,
                     tp->rx_std_ptr);
 
-       tp->rx_jumbo_ptr = (tp->tg3_flags & TG3_FLAG_JUMBO_ENABLE) ?
+       tp->rx_jumbo_ptr = (tp->tg3_flags & TG3_FLAG_JUMBO_RING_ENABLE) ?
                                                tp->rx_jumbo_pending : 0;
        tw32_rx_mbox(MAILBOX_RCV_JUMBO_PROD_IDX + TG3_64BIT_REG_LOW,
                     tp->rx_jumbo_ptr);
        if (tp->tg3_flags2 & TG3_FLG2_5750_PLUS)
                tp->tg3_flags2 |= TG3_FLG2_HW_TSO;
 
+       if (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5705 &&
+           GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5750 &&
+           GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5752)
+               tp->tg3_flags2 |= TG3_FLG2_JUMBO_CAPABLE;
+
        if (pci_find_capability(tp->pdev, PCI_CAP_ID_EXP) != 0)
                tp->tg3_flags2 |= TG3_FLG2_PCI_EXPRESS;
 
        /* Derive initial jumbo mode from MTU assigned in
         * ether_setup() via the alloc_etherdev() call
         */
-       if (tp->dev->mtu > ETH_DATA_LEN)
-               tp->tg3_flags |= TG3_FLAG_JUMBO_ENABLE;
+       if (tp->dev->mtu > ETH_DATA_LEN &&
+           GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5780)
+               tp->tg3_flags |= TG3_FLAG_JUMBO_RING_ENABLE;
 
        /* Determine WakeOnLan speed to use. */
        if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5700 ||