We have a pixhawk cube (3.6.9/master branch) connected to a Raspberry pi compute model via USB. Mavproxy on the Rpi intermittently display “no link” messages. During this nothing can be read from the pixhawk like “battery_status” or “SYS_STATUS” for example but, a reboot command goes through and reboots the pixhawk.
It appeared that MAVProxy wasn’t seeing any messages from the autopilot–none of the counters were updating AFAICT: “wp list” didn’t work; “param fetch” didn’t work
mavproxy did respond to commands, and showed that it was sending them to the autopilot,
just didn’t seem to be getting responses.
Running stty on the serial device (just opening + querying it) didn’t work. Well, it worked in that it’s able to open the device and retrieve the serial parameters, but it didn’t have any effect on the link status in mavproxy. Using stty to toggle the baud rate back and forth likewise.
Trying a restart of mavproxy… Link still down
“cat /dev/serial/by-id/usb-ArduPilot_fmuv3_23001D000B51383130383938-if00” seems to just return immediately.
Looks like read() on the FD is just returning zero, which is EOF as far as cat is concerned.
Has anyone else had this issue? I have never seen this while using NuttX.
Any help is appreciated