Hi i have a tl wr840n v4 it got 4 lan ports but the 4 lan ports are not showing individually they are showing eth0 eth0.1 and eth0.2 also in the lan filtering i cannot set vlan on the different ports.I need help in fixing that.
This sounds like a normal switch or Ethernet port.
VLANs already exist - VLAN 1 (eth0.1) and VLAN 2 (eth0.2). Can you better clarify?
There is nothing to 'fix', your device only has a single ethernet interface - which is then multiplexed via a managed (onboard) switch (still using swconfig drivers).