# DF-1274 PoC — tonga spread-spectrum divide-by-zero (LATENT)

**Status:** source-confirmed real; NOT reproducible on audit guest (no AMD GPU).
**Impact:** divide-by-zero (#DE) panic at powerplay init via crafted VBIOS usSpreadRateInKhz=0.
**Driver:** `sys/dev/drm/amd/powerplay/smumgr/tonga_smumgr.c` (amdgpu powerplay, not in GENERIC, no HW).
Sibling of DF-1204 (ni_dpm ss.rate).

## Reproduce
```
./build.sh && ./run.sh   # stub; bug path is GPU powerplay init
```
See `VERDICT.md` + `fix.diff`.