We are using 82576 Gigabit Ethernet Controller, as per the document (8.10.1 Receive Control Register - RCTL (0x00100; R/W)
, page No. 515) attached and also the ethtool output,
- Even if the UPE (Unicast Promiscuous Enable) bit is reset (disabled) we still seem to receive any Unknown Unicast Packets.
- If we disable the MPE (Multicast Promiscuous Enable) bit then we stop receiving any Unknown Unicast Packets.
While I do not see any reason why any one would disable UPE and enable MPE, just wanted to know if it is expected behavior.
Our assumption was that if the UPE bit is disabled then we should NOT receive any Unknown Unicast (assume we do not have any
RAL entries for MAC filtering)
Linux# ethtool -d eth1
0x00000: CTRL (Device control register) 0x40D00240
Invert Loss-Of-Signal: no
Receive flow control: disabled
Transmit flow control: disabled
VLAN mode: enabled
Set link up: 1
D3COLD WakeUp capability advertisement: enabled
Auto speed detect: disabled
Speed select: 1000Mb/s
Force speed: no
Force duplex: no
0x00008: STATUS (Device status register) 0x00080383
Link up: link config
DMA clock gating: disabled
TBI mode: disabled
Link speed: 1000Mb/s
Bus type: PCI Express
0x00100: RCTL (Receive control register) 0x0400803A
Store bad packets: disabled
Unicast promiscuous: disabled
Multicast promiscuous: enabled
Long packet: enabled
Descriptor minimum threshold size: 1/2
Broadcast accept mode: accept
VLAN filter: disabled
Cononical form indicator: disabled
Discard pause frames: filtered
Pass MAC control frames: don't pass
Loopback mode: normal
Receive buffer size: 2048
Currently we We don't have yet a definitive answer whether this is an expected behavior if both UPE and MPE are disabled.
We are still checking on this and we are seeing the same behavior as you are seeing.
Sure thanks for looking into it, please let us know as soon as you have something to share. We need to fix it for a up coming release.
Can you share What is the packet you are using and check if the destination address is really unicast vs. multicast. Thanks,