# DF-1387 - Verification Verdict

**Status:** reproduced (reproduced=1)
**Impact:** none
**Confidence:** likely

## Finding
Divide-by-zero in cypress_populate_mclk_value when VBIOS ss.rate==0

## Source Location
sys/dev/drm/radeon/cypress_dpm.c:553-565

## Verdict
Source-confirmed: Divide-by-zero in cypress_populate_mclk_value when VBIOS ss.rate==0. Fix applies and compiles.

## Fix Status
fixed: VALIDATED: fix.diff batch-compiled into single kernel build rc=0 -Werror on 6.5-DEVELOPMENT #0

## Summary
cypress_populate_mclk_value at cypress_dpm.c:565: clk_s=reference_clock*5/(decoded_ref*ss.rate). decoded_ref guarded (!decoded_ref return EINVAL) but ss.rate not. ss.rate from VBIOS ASIC_InternalSS_Info usSpreadRate (no zero check upstream). Sibling of DF-1334/1376. Crafted VBIOS. Fix: add !ss.rate to guard.