=== FIXED-KERNEL PARAMS TEST (DF-5135) — same kenv sequence, patched i915.ko ===
$ kenv KBUILD_MODNAME.verbose_state_checks=1 && kldload i915 && kldload ./i915probe.ko
$ sysctl hw.i915probe.params
dmabug:   error_capture=1  disable_display=0  verbose_state_checks=1  nuclear_pageflip=0
dmabug:   enable_dp_mst=1 enable_dpcd_backlight=0 enable_gvt=0
          ^^^^^^^^^^^^^^ INTACT (default true preserved; no neighbour corruption)