Mavlink Offboard and Jetson UART Issues

My team and I are using Jetsons, primarily an Xavier AGX, as a companion computer on a drone using PX4.

Offboard mode generally wants a Mavlink connection with a baudrate of 921600 or faster. When I tried this on my Jetson Nano, it would not receive data properly at any rate above 57600. After looking into the issue extensively, I found the UART drivers do not like Mavlink specifically or high data rates in general unless you add two stop bits, not an option here. I ended up using a Raspberry Pi as a serial to ethernet converter to get around this issue, proving this is a Jetson specific issue.

Fast forward a bit and we have similar but different issues on an Xavier AGX. Now, instead of receiving broken data at 115200 and above, we receive no Mavlink data whatsoever over UART at any speed. The process is as similar as possible but the results are even worse. This seems more fundamental than the driver issue I was seeing on the Nano.

Is there a possible step in setup or configuration we may be missing that is causing nothing to come through on the AGX?

hello g.brown2,

Jetson platforms by default using baudrate at 115200/8n1,
according to Xavier Series SoC Technical Reference Manual, it indicate that receiver always checks for 1 stop bit,
for example,

This information is both already known and does absolutely nothing to help come to a solution. 921600 is the required speed for this application and the AGX is receiving zero data at any baudrate.