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

[Jia Wang]

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