What does "RmInitAdapter failed!" mean, and what causes it?

I get “RmInitAdapter failed!” messages in dmesg on an embedded RHEL7.4 board, connected to Quadro Pascal GP107 in a 3U VPX chassis. What do these messages mean and how can I find out what is causing them?

I installed Cuda Toolkit v10.2, which bundles the 440.33.01 driver. I also tried installing the 510.60.02 driver, but that didn’t make a difference.

The first clue that something is wrong is that nvidia-smi give “No devices were found”, despite “lspci | grep - nvidia” showing the GPU as:

0c:00.0 VGA compatible controller: NVIDIA Corporation Device 1cba (rev a1)

Also, “cat /proc/driver/nvidia/version” shows the expected driver version number, whether 440.33.01 or 510.60.02.

“lsmod nvidia” also shows an nvidia driver loaded.