RGMII RX not working

[_J_M]

We have connected a PHY to the RGMII interface of the Jetson AGX Xavier.
When pinging out from the Jetson we see outgoing packets from the Jetson to the PHY, we see incoming packets from the PHY to the Jetson, but the Jetson does not show any received data.

Any ideas how to debug this? What could we check in the Jetson?

Thanks in advance

[kayccc]

Not sure which PHY you connected, could you check with vendor and see if they provide configuration?

[_J_M]

Hi,
thank you for your answer, please excuse my delayed answer.

The PHY is a
Microchip KSZ9131RNX

A lot is working:
The PHY link LED indicates that the link is up and stable.
The TX channel (Jetson → PHY → PC) is working.
On the RX channel (PC → PHY → Jetson) we see on the oscilloscope that the PHY is sending packets on the RGMII to the Jetson. The timing is what is expected from the Jetson (data and clock 90° shifted).
But the Jetson does not show any received data, see log below.
Is there a type of frame on the RGMII which would not be visible in the counters in the Jetson?

From a log from the debug uart:

sudo ethtool eth0

Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Link partner advertised pause frame use: Symmetric Receive-only
Link partner advertised auto-negotiation: Yes
Link partner advertised FEC modes: Not reported
Speed: 1000Mb/s
Duplex: Full
Port: MII
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: d
Wake-on: d
Link detected: yes

sudo ifconfig eth0

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.0.100 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::4ab3:2bff:fe7d:7c42 prefixlen 64 scopeid 0x20
ether 48:b3:2b:7d:7c:42 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 79 bytes 5543 (5.5 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 36

Best regards

[_J_M]

The problem was solved later.
I do not know the details but it was not a hardware problem. Due to some wrong configuration in the operating system the received frames were filtered out so it looked as if no frames were received in the Jetson.

Best regards