[PATCH net] net: dsa: mt7530: don't change PVC_EG_TAG when CPU port becomes VLAN-aware

[Arınç ÜNAL]

One last thing. Specific to MT7530 switch in MT7621 SoC, if port at 5 is 
the only CPU port defined on the devicetree, frames sent from DSA master 
appears malformed on the user port. Packet capture on computer connected 
to the user port is attached.

The ARP frames on the pcapng file are received on the DSA master, I 
captured them with tcpdump, and put it in the attachments. Then I start 
pinging from the DSA master and the malformed frames appear on the 
pcapng file.

It'd be great if you could take a look this final issue.

Arınç
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# tcpdump -i eth0
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on eth0, link-type NULL (BSD loopback), snapshot length 262144 bytes
00:00:16.763653 AF Unknown (4294926075), length 56: 
	0x0000:  9a17 e0d5 5ea4 edcc 0826 c0a8 0201 0000  ....^....&......
	0x0010:  0000 0000 0000 0000 0000 0000 0000 0000  ................
	0x0020:  1206 020c d14b 0003 3d4f 3030 3030 1030  .....K..=O0000.0
	0x0030:  3100 3030                                1.00
00:00:17.789246 AF Unknown (4294909691), length 184: 
	0x0000:  9a07 e0d5 5ea4 edcc 2daf 0001 0800 0604  ....^...-.......
	0x0010:  0001 e0d5 5ea4 4ccc 8000 0202 0000 0000  ....^.L.........
	0x0020:  0020 c0a8 0201 0000 0000 0000 0000 0000  ................
	0x0030:  0000 0000 0000 0000 9a07 0000 0000 0000  ................
	0x0040:  2103 0000 0000 0000 0006 0000 0003 0000  !...............
	0x0050:  0118 0000 012e 0000 0002 0000 0000 0000  ................
	0x0060:  0000 0000 005f 0000 0003 0000 0000 0000  ....._..........
	0x0070:  0045 0000 0003 0000 0008 0000 0038 0000  .E...........8..
	0x0080:  0200 0000 0100 0000 0003 0000 0004 0000  ................
	0x0090:  0003 0000 0003 0000 0123 0000 000c 0000  .........#......
	0x00a0:  0003 0000 0000 0000 010c 0000 0004 0000  ................
	0x00b0:  0003 0000                                ....
00:00:18.813241 AF Unknown (4294926075), length 56: 
	0x0000:  9a17 e0d5 5ea4 edcc 29a6 c0a8 0201 0000  ....^...).......
	0x0010:  0000 0000 0000 0000 0000 0000 0000 0000  ................
	0x0020:  9a07 020c e251 0003 394c 3035 2031 1430  .....Q..9L05.1.0
	0x0030:  3a8e 2031                                :..1
00:00:19.837223 AF Unknown (4294926079), length 70: 
	0x0000:  9a07 e0d5 5ea4 edcc 29af 0001 0800 0604  ....^...).......
	0x0010:  0001 e0d5 5ea4 4ccc 8000 0202 0000 0000  ....^.L.........
	0x0020:  0000 c0a8 0201 0000 0000 0000 0000 0000  ................
	0x0030:  0000 0000 0000 0000 9a07 020c a38a 0003  ................
	0x0040:  2103                                     !.
00:00:20.861219 AF Unknown (4294926079), length 56: 
	0x0000:  9ad7 e0d5 5ea4 edcc 2daf c0a8 0201 0000  ....^...-.......
	0x0010:  0000 0000 0000 0000 0000 0000 0000 0000  ................
	0x0020:  9a07 004c aa20 0003 3948 0000 0000 0000  ...L....9H......
	0x0030:  2100 0000                                !...
00:00:21.885217 AF Unknown (4294909691), length 56: 
	0x0000:  9a07 c0a8 0201 0000 2121 0000 0000 0000  ........!!......
	0x0010:  0000 0000 0000 0000 9a07 020c 25a9 0003  ............%...
	0x0020:  2104 0000 0170 4832 0200 0000 0003 0000  !....pH2........
	0x0030:  2104 0000                                !...
^C
6 packets captured
6 packets received by filter
0 packets dropped by kernel
# ping 192.168.2.2
PING 192.168.2.2 (192.168.2.2): 56 data bytes
^C
--- 192.168.2.2 ping statistics ---
7 packets transmitted, 0 packets received, 100% packet loss
# 
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A non-text attachment was scrubbed...
Name: new-mt7530-port5-malformed.pcapng
Type: application/x-pcapng
Size: 1848 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-mediatek/attachments/20230206/6b47ea6a/attachment-0001.bin>