Programmer’s Guide BCM5722
10/15/07
Broadcom Corporation
Document 5722-PG101-R Page 52
• When the RSS Hash Valid flag bit is 1, the RSS Hash field holds the 32-bit RSS hash value calculated for a packet. This
field should be ignored when the RSS Hash Valid flag bit is zero.
• The Opaque field is reserved for the host software driver. Any data placed in this field in a producer ring descriptor will
be passed through unchanged to the corresponding return ring descriptor.
Table 17: Defined Error Flags for Receive Buffers
Bits Name Description
31:9 Reserved Should be set to 0.
8 GIANT_PKT_RCVD If set to 1, the received packet was longer than the maximum packet length value set in
the Receive MTU Size register (see “Receive MTU Size Register (Offset 0x43C)” on
page 250). The data in the received packet was truncated at the length specified in the
Receive MTU Size register.
7 TRUNC_NO_RES If set to 1, the received packet was truncated because the controller did not have the
resources to receive a packet of this length.
6 LEN_LESS_64 If set to 1, the received packet was less than the required 64 bytes in length.
5 MAC_ABORT If set to 1, the MAC aborted due to an unspecified internal error while receiving this
packet. The packet could be corrupted.
4 ODD_NIBBLE_RX_MII If set to 1, the received packet contained an odd number of nibbles. Thus, packet data
could be corrupt.
3 PHY_DECODE_ERR If set to 1, while receiving this packet the device encountered an unspecified frame
decoding error. This packet could be corrupted.
This bit is set for valid packets that are received with a dribble nibble. True alignment
errors will be dropped by that mac and never show up to the driver.
2 LINK_LOST If set to 1, link was lost while receiving this frame. Therefore this packet is incomplete.
1 COLL_DETECT If set to 1, a collision was encountered while receiving this packet.
0 BAD_CRC If set to 1, the received packet has a bad Ethernet CRC.
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