USB Driver sometimes not Initialized after boot

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
1

Hey Nvidia people,

Currently I have custom board that connect the usb port of jetson nano to USB-UART chip for serial.
In normal condition after the jetson nano is booted up, I can see /dev/ttyUSB0 (actually up to /dev/ttyUSB2 since I connect 3 of it) and everything works fine.
However some of the time after I power it, I cannot see any /dev/ttyUSB*, it maybe happens 3/10. This problems disappear after I power cycle.
My questions is why it is like this and is there some modification in kernels I can do to avoid this?
If not, is there a command to reset usb driver after boot?

Best Regards,
Andreas Widy

3

Hi,
We suggest do compliance test on the custom board. To make sure the signal is good. Please take a look at
https://developer.nvidia.com/jetson-nano-interface-tuning-and-compliance-guide-application-note

4

@andreaswidy,

I have this problem consistently with the Intel T265 and I found that I had to power cycle the USB ports to get the T265 to respond.

Install uhubctl

cd /usr/sbin/
sudo ./uhubctl -a cycle -l 1 -p 1-4
sudo ./uhubctl -a cycle -l 2 -p 1-4

Regards, TCIII