topic Re: Unstable Gigabit Ethernet on i.MX 8M Mini in i.MX Processors

Unstable Gigabit Ethernet on i.MX 8M Mini

yuping1 — Mon, 04 Nov 2024 11:20:11 GMT

Hi all,

We have a custom designed board based on i.MX 8M Mini running Android 9.0 and we're experiencing an issue with gigabit ethernet. The connection will randomly drop out and self recover again randomly later. We tried to ping the router or other devices on the same LAN and got the same issue. Ping would fail randomly for several seconds or sometimes several minutes.

We checked the kernel log and found many 'Link is Down' message followed by many 'Link is Up' message when the connection is lost. We suspect it might an issue with our kernel dts config or the FEC driver but we couldn't spot any obvious errors.

The ethernet phy chip used is RTL8211E-VB-CG and it is used on some of our other rockchip boards as well and those do not have such problem.

One thing we did notice is that in the rockchip kernel dts, there are two properties 'tx_delay' and 'rx_delay' that can be modified to adjust the timings. We did not find similar values to change on the i.MX platform. The RTL8211E chip has two hardware pins that set the RX/TX delay as specified in the datasheet.

We tested both configurations. 'no delay' doesn't work at all and '2ns delay' produces the issue described here.

Any help or information will be appreciated.

Regards,

Yuping

Re: Unstable Gigabit Ethernet on i.MX 8M Mini

yuping1 — Mon, 04 Nov 2024 11:26:59 GMT

Here are the dts for i.MX board:

&fec1 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_fec1>; phy-mode = "rgmii-id"; phy-handle = <&ethphy0>; fsl,magic-packet; status = "okay"; mdio { #address-cells = <1>; #size-cells = <0>; ethphy0: ethernet-phy@0 { compatible = "ethernet-phy-ieee802.3-c22"; reg = <0>; at803x,led-act-blind-workaround; at803x,eee-okay; at803x,vddio-1p8v; }; }; };

Below is the dts for rockchip board:

&gmac1 { phy-mode = "rgmii"; clock_in_out = "output"; snps,reset-gpio = <&gpio4 RK_PC2 GPIO_ACTIVE_LOW>; snps,reset-active-low; snps,reset-delays-us = <0 50000 50000>; assigned-clocks = <&cru SCLK_GMAC1_RX_TX>, <&cru SCLK_GMAC1>; assigned-clock-parents = <&cru SCLK_GMAC1_RGMII_SPEED>, <&cru CLK_MAC1_2TOP>; assigned-clock-rates = <0>, <125000000>; pinctrl-names = "default"; pinctrl-0 = <&gmac1m1_miim &gmac1m1_tx_bus2 &gmac1m1_rx_bus2 &gmac1m1_rgmii_clk &gmac1m1_rgmii_bus>; tx_delay = <0x24>; rx_delay = <0x08>; phy-handle = <&rgmii_phy1>; status = "okay"; }; &mdio1 { rgmii_phy1: phy@7 { compatible = "ethernet-phy-ieee802.3-c22"; reg = <0x7>; }; };

Re: Unstable Gigabit Ethernet on i.MX 8M Mini

Bio_TICFSL — Mon, 04 Nov 2024 14:14:20 GMT

Hello,

You dtb looks ok, I guess your issue if due to RTL8211E, So please check your HW setting Vs PHY datasheet (PHY address, clock delay, SELRGV, etc..) and schematics.

If you received 0 bytes, looks like your receive path is broken. Please check the pin definition/muxing in DT, receive clock settings in the PHY and the RCC, as well as connection/timings configurations at PHY level.

regards

Re: Unstable Gigabit Ethernet on i.MX 8M Mini

Only_聆听 — Tue, 03 Dec 2024 12:43:27 GMT

Hello, I have encountered the same problem as him. The log shows that the network has been switching between 10M, 100M, and 1000M.

[19:40:02.502]收←◆[ 227.550570] fec 30be0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx

[19:40:18.885]收←◆[ 243.934572] fec 30be0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx

[19:40:20.021]收←◆[ 245.070298] healthd: battery l=85 v=3 t=35.0 h=2 st=2 c=400 fc=4000000 cc=32 chg=a

[19:40:20.118]收←◆[ 245.167955] healthd: battery l=85 v=3 t=35.0 h=2 st=2 c=400 fc=4000000 cc=32 chg=a

[19:40:32.196]收←◆[ 257.246587] fec 30be0000.ethernet eth0: Link is Up - 10Mbps/Half - flow control off

[19:40:43.460]收←◆[ 268.511081] fec 30be0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx

[19:41:20.017]收←◆[ 305.070247] healthd: battery l=85 v=3 t=35.0 h=2 st=2 c=400 fc=4000000 cc=32 chg=a

[19:41:20.115]收←◆[ 305.167936] healthd: battery l=85 v=3 t=35.0 h=2 st=2 c=400 fc=4000000 cc=32 chg=a

[19:42:11.517]收←◆[ 356.574683] fec 30be0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx

[19:42:20.013]收←◆[ 365.070404] healthd: battery l=85 v=3 t=35.0 h=2 st=2 c=400 fc=4000000 cc=32 chg=a

[19:42:20.110]收←◆[ 365.167999] healthd: battery l=85 v=3 t=35.0 h=2 st=2 c=400 fc=4000000 cc=32 chg=a

[19:42:43.260]收←◆[ 388.319071] fec 30be0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx

[19:43:01.691]收←◆[ 406.751070] fec 30be0000.ethernet eth0: Link is Up - 10Mbps/Half - flow control off

Re: Unstable Gigabit Ethernet on i.MX 8M Mini

Only_聆听 — Tue, 03 Dec 2024 12:49:55 GMT

I used to think it was caused by energy-saving mode, but in DTS, it was declared to disable all EEE modes, but the problem still exists. The phy I am using is RTL8211E-VB-CG