The proprietary driver's DRM card says DRIVER=nvidia, which the driver list did not know, so the card was never enumerated; and it exposes no sysfs busy counter or fdinfo engine totals. Read it with nvidia-smi instead (--query-gpu per sample, pmon -c 1 -s um for clients), by PCI address. Parsers unit-tested, including an older pmon column layout and [N/A] fields. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>