Error message

xillybus: Failed to obtain major/minors

Meaning

This error is a result of the Linux kernel refusing to allocate major/minor pairs, which are the code numbers connecting internally between a device file and its driver. This condition is very unexpected, and may indicate an unhealthy software condition of the host.

Recommended action

Rebooting the host may clear any Linux kernel instabilities, which are likely to be the reason for this error.