# DF-1301 - Verification Verdict

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

## Finding
Display scaling math divides by stream/plane rect dimensions with no zero guard (kernel #DE panic)

## Source Location
sys/dev/drm/amd/display/dc/core/dc_resource.c:635-755

## Verdict
Source-confirmed: Display scaling math divides by stream/plane rect dimensions with no z. 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
calculate_scaling_ratios/recout/viewport at dc_resource.c: div64_s64 and int divisions by stream->src/dst.width/height and plane dst_rect.width/height with NO zero check. div64_s64 is plain dividend/divisor. resource_build_scaling_params calls calculate_scaling_ratios BEFORE the only size sanity check. Currently bounded: amdgpu_dm rejects zero rects, underscan capped at 128 < h/v_addressable. Speculative: future path bypassing rect validation -> #DE panic. Fix: add zero-rect guard at top of reso