reading igb_up, get
1. take over ownership from firmware to device driver
2. setup rx mode
3. set MRQC(hash seeds, RSS, hash packet types)
4. configure tx,rx ring (allocating tx ring and rx dma ranges, tail and header pointers)
5. flush the rx dma, drop the 'bad' packets in front of the rx fifo.
6. know that we don't use VM mode, as there is no multi operation system used

next step is reading : igb_configure_MSIX