The most recent edition of the ixgbe driver is not capturing ethernet frames when put into promiscuous mode if the input traffic is tagged in 802.1q mode.
I have confirmed this by enabling promiscuous mode on the card, watching the counters increment rapidly (this is on a tap port), and then using "tcpdump -s 0 -ni eth6" to view traffic. The traffic that arrives is no the amount or expected type of traffic (only a 1 SNAP ethernet frame every 6 or 10 seconds, while the counters increment at about 1.2 GB/s).
I have created a vlan device using "vconfig add eth6 80" and then a "tcpdump -s 0 -ni eth6.80" and observing a large quantity of traffic of the expected type.
My understanding is that in promiscuous mode, the card should disable the rxvlan filters and simply pass all traffic to the host. If this is the intended behavior, then I suspect that there is a bug present. I've looked over the code in ixgbe_main.c and looked at the register setting methods for the VLAN filter stuff and it appears correct to me, so I'm kicking it up to the masters. I've also confirmed that the vlan registers both show disabled in "ethtool -d eth6", with the below results:
0x05080: FCTRL (Filter Control register) 0x00000400
Broadcast Accept: enabled
Unicast Promiscuous: enabled
Multicast Promiscuous: enabled
Store Bad Packets: disabled
0x05088: VLNCTRL (VLAN Control register) 0x40008100
VLAN Mode: disabled
VLAN Filter: disabled
Additionally, here's the "lspci -v" output for the device in question:
08:00.0 Ethernet controller: Intel Corporation 82599EB 10-Gigabit SFI/SFP+ Network Connection (rev 01)
Subsystem: Intel Corporation Ethernet Server Adapter X520-2
Flags: bus master, fast devsel, latency 0, IRQ 202
Memory at d9900000 (64-bit, prefetchable) [size=512K]
I/O ports at bcc0 [size=32]
Memory at d98f8000 (64-bit, prefetchable) [size=16K]
Capabilities:  Power Management version 3
Capabilities:  MSI: Enable- Count=1/1 Maskable+ 64bit+
Capabilities:  MSI-X: Enable+ Count=64 Masked-
Capabilities: [a0] Express Endpoint, MSI 00
Capabilities:  Advanced Error Reporting
Capabilities:  Device Serial Number 90-e2-xx-xx-xx-xx-xx-xx
Capabilities:  Alternative Routing-ID Interpretation (ARI)
Capabilities:  Single Root I/O Virtualization (SR-IOV)
Kernel driver in use: ixgbe
Kernel modules: ixgbe
Thanks for all that you do folks, it's a great service, and not an easy job.