If the Holoscan visualizer is not able to access the host display, the program will usually crash with a segmentation fault. Make sure that xhost + is executed on the host system before running the Holoscan application and make sure the DISPLAY environment variable is set properly in the container where the application is run.
The hololink enumerate command, in the demo container, can be used to monitor enumeration messages sent by the sensor bridge device. If no messages appear, then check for power to the sensor bridge device, physical connections to the device, and appropriate network configurations as listed above. ping 192.168.0.2 and ping 192.168.0.3 can also be used to check for connectivity.
If there are no error messages on the application console, then it indicates that the control plane is able to connect but there is no data being received on the data plane. For unaccelerated network connections, tcpdump can be used to determine if traffic is being sent from the sensor bridge device. In accelerated network configurations, the ConnectX NIC hides the data plane traffic from the CPU, so tcpdump will not report it. Instead, you can check the packet receiver counter this way:
cat /sys/class/infiniband/mlx5_0/ports/1/hw_counters/rx_write_requests
or, to see all counters published by the ConnectX driver,
for i in /sys/class/infiniband/mlx5_0/ports/1/counters/*; do
echo -n $i
echo -n ": "
cat $i
done
Use the appropriate value where mlx5_0 is shown here. When no data plane requests are received, be sure and check that the sensor is properly connected to the sensor bridge board.