Hi Andrew,

On 1/21/2026 8:55 PM, Andrew Lunn wrote:

quoted

@@ -721,6 +719,7 @@ rgmii_phy0: ethernet-phy@1 {
 		reset-assert-us = <20000>;
 		reset-deassert-us = <100000>;
 		reset-gpios = <&gpio2 RK_PB5 GPIO_ACTIVE_LOW>;
+		tx-internal-delay-ps = <1950>;

The PHY should add 2000ps, as required by the RGMII standard. The
difference is so small there is no need for tx-internal-delay.

Thank you for the clarification. I chose 1950 here because I find that
the MotorComm yt8xxx Ethernet PHY binding only offer the options of 
1950 or 2100. 

In most cases, 'rmgii-id' should be sufficient, unless the PCB is
badly designed.

I suspect the ROCK 4D board might be an exception. Sebastian once
reported that it wouldn't work properly under "rgmii-id". Well, I'm
not sure what strategy to adopt in this case.

-- 
Best, 
Chaoyi