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K606's avatar
K606
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2 months ago

Agilex 5 EMAC GMII loopthrough: signals are not toggling in Fabric

I am trying to route GMII signals through the Agilex5 HPS to the Fabric. In the .dts I am using, I have the following settings for the two EMACs: &gmac0 { status = "okay"; mac-mode = "gmii"; ph...
embedded peripheral
general
Hps Debug
ShunJingG_Altera's avatar
ShunJingG_Altera
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2 months ago

hi,

thank you for the clarifications.

If ping works and you can see the signals toggling, i believe the loopback design is working from hardware perspective. The original issue for the discussion is actually solved right?

For the arping timeout. I believe we need to investigate from Linux.

From your screenshot, i can see that the tx packet from cat /proc/net/dev actually increased. I am not sure if the increment from 68 to 73 for tx is due to the arping. Could you please help to check that?

If the answer is yes, maybe there are configurations needed to handle looped ARP packets.

These are the things that i have found to bypass some checks in linux:

echo 1 > /proc/sys/net/ipv4/conf/eth1/accept_local
echo 1 > /proc/sys/net/ipv4/conf/eth1/arp_ignore
echo 1 > /proc/sys/net/ipv4/conf/eth1/rp_filter

Here are the commands that you can use to debug further:

tcpdump -i eth1 -e -vv
K606's avatar
K606
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2 months ago

Thanks - I will try this and see if it works

  • BoonBengT_Altera's avatar
    BoonBengT_Altera
    Icon for Moderator rankModerator
    1 month ago

    Dear K606 ,

    Since clarification has been provided and no further follow‑up questions have been raised, we will assume the issue has been resolved. 
    This thread will now be transitioned to community support, where other users can continue to assist with any additional inquiries.
    For new questions, please feel free to open a fresh thread — we’ll be happy to support you there.

    Thank you for being part of the community!

    Best regards,
    Altera Technical Support