Guest environment probe (2026-09-24, by df-bsd-reviewer during pass-2 audit of
sys/dev/drm/i915/intel_csr.c + sys/dev/drm/amd/amdgpu/mmhub_v1_0.c).

$ uname -a
DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026     root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64

$ pciconf -l   (as root)
hostb0@pci0:0:0:0:   class=0x060000 card=0x11001af4 chip=0x12378086 rev=0x02 hdr=0x00  # i440FX
isab1@pci0:0:1:0:    class=0x060100 card=0x11001af4 chip=0x70008086 rev=0x00 hdr=0x00
atapci0@pci0:0:1:1:  class=0x010180 card=0x11001af4 chip=0x70108086 rev=0x00 hdr=0x00
none0@pci0:0:1:3:    class=0x068000 card=0x11001af4 chip=0x71138086 rev=0x03 hdr=0x00
vgapci0@pci0:0:2:0:  class=0x030000 card=0x11001af4 chip=0x11111234 rev=0x02 hdr=0x00  # QEMU std VGA (vendor 0x1234)
virtio_pci0@pci0:0:3:0: class=0x020000 ... (virtio-net)
virtio_pci1@pci0:0:4:0: class=0x010000 ... (virtio-blk)

CONCLUSION (testability):
- The only display device is the QEMU/Red Hat std-VGA (0x1234:1111).
- There is NO Intel gen9+ (SKL/BXT/GLK/KBL/CNL/ICL) i915 device, so
  intel_csr_ucode_init()/csr_load_work_fn()/parse_csr_fw() can never execute
  on this guest (they are gated on HAS_CSR(), which needs gen9+ hardware).
- There is NO AMD Vega10/Raven MMHUB, so mmhub_v1_0_* can never execute.
=> Runtime PoC of DF-4814 / DF-4815 on this guest is impossible
   (device absent, not merely unconfigured). The DF-4814 pack therefore
   carries a guest-compiled host-logic harness that replicates the exact
   parse loop on the exact packed struct definitions instead.