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Zach2's avatar
Zach2
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3 years ago

Arria 10 HPS EMAC with KSZ9131 PHY

We've developed a custom Arria 10 SX board that pairs a KSZ9131 Ethernet PHY with the HPS EMAC, and using Linux 5.4 we see inconsistent Ethernet behavior depending on whether the link has gone down: ...
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gschuell's avatar
gschuell
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3 years ago

Hi Zach,

I'm assuming from your initial post that you are using the HPS EMAC (from Synopsys). Is this correct?

We are running into a very similar problem with our custom Arria 10 SX board and the KSZ9131 PHY. We seem to be able to transmit properly but never receive successfully. We are running our ping tests in U-Boot rather than Linux for now.

Have you had any luck in resolving your problem?

Thanks,

Greg

Zach2's avatar
Zach2
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3 years ago

Hi Greg,

I'm assuming from your initial post that you are using the HPS EMAC (from Synopsys). Is this correct?

That's correct.

We've been able to work around the problem in Linux by adding the following properties to the PHY device tree node:

eee-broken-100tx;
eee-broken-1000t;

These disable advertisement of EEE in the Arria 10's PHY so that even if the link partner advertises EEE, it doesn't get enabled.

Since both the the KSZ9131 PHY and HPS EMAC claim to support EEE, we're still not sure why this is necessary.

I'm not sure if U-Boot has the same (or equivalent) device tree properties to disable EEE.

Zach