Work around to turn off RJ45 LEDs


We are using Jetson NX module in one of our custom carrier board. We want to turn off the LEDs on RJ45 connector, is there any work around to do it via software?

hello venkatraman.bhat,

are you able to use Jetson-IO to control it?
may I know what’s the actual use-case to disable it, would you like to fully disable LEDs on RJ45?

I am not sure how to do this. Please guide me, you are talking about GPIOs? no right?

Customer wants to use in some observatory where they dont want light distraction. yes, they would like to fully disable LEDs on RJ45

The GBE LED on RJ45 is generally controlled by the ethernet phy. If you change the phy, then you need to consult with the vendor to know how to control it.

If you didn’t change the default phy and stick to the same as NX devkit, then your PHY is probably RTL8211FDI as design guide says.

For such case, the phy driver in kernel should be kernel/kernel-4.9/drivers/net/phy/realtek.c. Please consult with Realtek for the datasheet of this PHY. There will be the info for the LED control register. Use phy_write and phy_read to control this register and see if the LED behavior is changed or not.

Thank you,

it worked for me with this tool. need to add the commands in boot script if want to run during boot.

root@nvidia-desktop:/home/nvidia/phy/phytool# ./phytool write eth0/0/0x1f 0x0d04
root@nvidia-desktop:/home/nvidia/phy/phytool# ./phytool read eth0/0/0x10 0x0000
root@nvidia-desktop:/home/nvidia/phy/phytool# ./phytool write eth0/0/0x10 0x0000

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