Re: [PATCH 12/12] riscv: dts: ultrarisc: Add Milk-V Titan board device tree

On 2026-08-24 15:06 +0200, Andrew Lunn wrote:

quoted

+&ethernet {
+	phy-handle = <&phy0>;
+	/*
+	 * RTL8211F: board timing uses PHY strap delays; keep plain "rgmii".
+	 * Enabling PHY internal delays via "rgmii-id" breaks Ethernet traffic.

This actually indicates something is wrong.

When passed PHY_INTERFACE_MODE_RGMII, the PHY driver should change the
PHY to not add delays, overriding the strapping.

Given my previous comment, you need to spend some time understanding
what is going on here. Something is not correct.

https://elixir.bootlin.com/linux/v6.15/source/Documentation/devicetree/bindings/net/ethernet-controller.yaml#L287

Thanks for pointing this out. You are right that the RTL8211F driver
disables its internal delays for "rgmii", so the strap-delay explanation
was incorrect.

The same fixed DP1000 TX and RX RGMII clock skew described in my M0 reply
applies here. I will correct the comment in the next version.

	Andrew

Best regards,
Jia Wang