Guest: DragonFly dfbsd 6.5-DEVELOPMENT (audit QEMU/KVM guest, X86_64_GENERIC base)
uname -a (stock GENERIC boot):
  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

Display hardware (pciconf -l):
  vgapci0@pci0:0:2:0: class=0x030000 card=0x11001af4 chip=0x11111234 rev=0x02 hdr=0x00
  -> 0x1234:1111 = Bochs/QEMU std VGA. NO ATI/AMD GPU present.

Kernel config (sys/config/X86_64_GENERIC): no `radeon` device line either
(the radeon driver is only loadable and has no hardware to bind to).

Conclusion: sys/dev/drm/radeon/dce6_afmt.c cannot execute on this guest --
dce6_* code paths run only on DCE6+ (Tahiti and later) radeon ASICs after
radeon_device_init -> radeon_audio_init. Reproduction of DF-5028 would
require SI/CIK-class hardware (or GPU passthrough) with a VBIOS whose
LVDS_Info table is missing/unparsable while a digital encoder has
ATOM_DEVICE_LCD_SUPPORT, or forced kzalloc failure during encoder creation.