Jetson Thor - mgbe0_0 down - <no-carrier>

Robotics & Edge Computing Jetson Systems Jetson Thor
1

Hi,

I’m trying to get mgbe0_0 up on my NVIDIA Jetson AGX Thor Developer Kit without success.

cat /etc/nv_tegra_release
    # R38 (release), REVISION: 4.0, GCID: 43443517, BOARD: generic, EABI: aarch64, DATE: Wed Dec 31 00:15:19 UTC 2025
    # KERNEL_VARIANT: oot
    TARGET_USERSPACE_LIB_DIR=nvidia
    TARGET_USERSPACE_LIB_DIR_PATH=usr/lib/aarch64-linux-gnu/nvidia
    INSTALL_TYPE=

I use a 40G QSFP+ to 4 x 10G SFP+ Cable connect to 10GBase-X SFP+ to 1000Base-T RJ45 media converter. The other 3 lanes of the cable are not connect.

Cable: Similar to this Cisco QSFP-4SFP10G-CU1M 40G QSFP+ Breakout DAC Cable - FS.com Europe
Media Converter: Amazon.com

Questions

  1. Is it possible to run mgbe0_0 standalone without connecting the other 3 SFP+ lanes?
  2. Is my setup with a breakout cable and media converter possible?
  3. Any other ideas for a test setup?

Logs

ip -br link show mgbe0_0
    mgbe0_0          DOWN           3c:6d:66:e4:0b:9b <NO-CARRIER,BROADCAST,MULTICAST,UP>

ethtool mgbe0_0
    Settings for mgbe0_0:
        Supported ports: [ TP    MII ]
        Supported link modes:   Not reported
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  Not reported
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: 10000Mb/s
        Duplex: Full
        Auto-negotiation: on
        Port: MII
        PHYAD: 0
        Transceiver: external
        Supports Wake-on: d
        Wake-on: d
        Current message level: 0x00000000 (0)

        Link detected: no

dmesg | grep a808a10000
    [    9.091884] nvpps c230000.nvpps: primary-emac : ethernet@a808a10000
    [    9.183347] nvethernet a808a10000.ethernet: Adding to iommu group 50
    [    9.184769] nvethernet a808a10000.ethernet: Virtualization is not enabled
    [    9.184774] nvethernet a808a10000.ethernet: failed to read skip mac reset flag, default 0
    [    9.184776] nvethernet a808a10000.ethernet: failed to read MDIO address
    [    9.184780] nvethernet a808a10000.ethernet: Failed to read nvida,pause_frames, so setting to default support as disable
    [    9.184783] nvethernet a808a10000.ethernet: Failed to read nvida,disable-rx-checksum, so setting to default - rx checksum offload enabled
    [    9.184786] nvethernet a808a10000.ethernet: setting to default DMA bit mask
    [    9.188696] nvethernet a808a10000.ethernet: failed to read or invalid MDC CR - default to 5
    [    9.188799] nvethernet a808a10000.ethernet: failed to get phy reset gpio error: -2
    [    9.234320] nvethernet a808a10000.ethernet: Ethernet MAC address: 3c:6d:66:e4:0b:9b
    [    9.238134] nvethernet a808a10000.ethernet: VM IRQ is handled by Camera CPU: 4
    [    9.263915] nvethernet a808a10000.ethernet: DT info about vlan in clear is missing setting default-disabled
    [    9.268868] nvethernet a808a10000.ethernet: Macsec: Reduced MTU: 1466 Max: 9000
    [    9.281775] nvethernet a808a10000.ethernet: mgbe0_0 (HW ver: 42) created with 4 DMA channels
    [    9.541011] camrtc-coe tegra-capture-coe0: Camera Over Eth controller a808a10000.ethernet num_chans=5 IRQ=4

Thanks,

Holger

3

This is the one I got that works on my Thor. NVIDIA/Mellanox MC2609130-001. The one you got might work, I don’t know it.

I’ve got 3 SFP+ lanes connected and up. And one disconnected and not up or configured. And at first I just had mgbe0_0 connected and that worked.

I don’t know about media converter. I’ve got a QNAP QSW-2104-2S-A-US: 2.5GbE RJ45 & 10G SFP+ switch that works well.

4

The media converter was the problem. With a switch it worked as expected.

Thanks