best_effort_vlan_filtering [DEVICE, DRIVER-SPECIFIC] Allow plain ETH_P_8021Q headers to be used as DSA tags. Benefits: - Can terminate untagged traffic over switch net devices even when enslaved to a bridge with vlan_filtering=1. - Can terminate VLAN-tagged traffic over switch net devices even when enslaved to a bridge with vlan_filtering=1, with some constraints (no more than 7 non-pvid VLANs per user port). - Can do QoS based on VLAN PCP and VLAN membership admission control for autonomously forwarded frames (regardless of whether they can be terminated on the CPU or not). Drawbacks: - User cannot use VLANs in range 1024-3071. If the switch receives frames with such VIDs, it will misinterpret them as DSA tags. - Switch uses Shared VLAN Learning (FDB lookup uses only DMAC as key). - When VLANs span cross-chip topologies, the total number of permitted VLANs may be less than 7 per port, due to a maximum number of 32 VLAN retagging rules per switch. Configuration mode: runtime Type: bool.