Very poor network performance is observed on the ODROID-M1 Board
(REV 1.0 20220613) when running iperf3 (under 200Mbits/sec), and
this problem can be resolved after changing the value of TXD
timing to 0x35 from 0x4f.

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
---
 arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts b/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts
index 0f844806ec542..e1a550a04498e 100644
--- a/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts
@@ -210,7 +210,7 @@ &gmac0_rgmii_clk
 		     &gmac0_rgmii_bus>;
 	status = "okay";
 
-	tx_delay = <0x4f>;
+	tx_delay = <0x35>;
 	rx_delay = <0x2d>;
 };
 
-- 
2.34.1

Hi,

> Very poor network performance is observed on the ODROID-M1 Board
> (REV 1.0 20220613) when running iperf3 (under 200Mbits/sec), and
> this problem can be resolved after changing the value of TXD
> timing to 0x35 from 0x4f.

Can you try changing phy-mode to "rgmii-id" ?

```
--- a/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts
@@ -200,7 +200,7 @@ &gmac0 {
 	assigned-clock-rates = <0>, <125000000>;
 	clock_in_out = "output";
 	phy-handle = <&rgmii_phy0>;
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 	phy-supply = <&vcc3v3_sys>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&gmac0_miim
@@ -209,9 +209,6 @@ &gmac0_rx_bus2
 		     &gmac0_rgmii_clk
 		     &gmac0_rgmii_bus>;
 	status = "okay";
-
-	tx_delay = <0x4f>;
-	rx_delay = <0x2d>;
 };
 
 &gpu {
```

--
2.25.1

On Tue, Aug 19, 2025 at 11:10:19PM +0800, Chukun Pan wrote:
> Hi,
> 
> > Very poor network performance is observed on the ODROID-M1 Board
> > (REV 1.0 20220613) when running iperf3 (under 200Mbits/sec), and
> > this problem can be resolved after changing the value of TXD
> > timing to 0x35 from 0x4f.
> 
> Can you try changing phy-mode to "rgmii-id" ?
> 
> ```
> --- a/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts
> @@ -200,7 +200,7 @@ &gmac0 {
>  	assigned-clock-rates = <0>, <125000000>;
>  	clock_in_out = "output";
>  	phy-handle = <&rgmii_phy0>;
> -	phy-mode = "rgmii";
> +	phy-mode = "rgmii-id";
>  	phy-supply = <&vcc3v3_sys>;
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&gmac0_miim
> @@ -209,9 +209,6 @@ &gmac0_rx_bus2
>  		     &gmac0_rgmii_clk
>  		     &gmac0_rgmii_bus>;
>  	status = "okay";
> -
> -	tx_delay = <0x4f>;
> -	rx_delay = <0x2d>;
>  };
>  
>  &gpu {
> ```
> 
> --
> 2.25.1
> 
> 
Thank you for suggesting me to try 'rgmii-id' again.

I'd remember that 'rgmii-id' didn't work with the very early version of
the board, however your suggestion works. Let me test the change with
more boards and submit the new patch when it's done.

Thanks a lot.
Dongjin Kim.