=== DF-4738 run (guest) ===
before: pcie0 (firmware-configured) owns secondary bus 2
after : cbb0 (SECBUS=0 from firmware) renumbered to secbus=2 subbus=3
=> COLLISION: two bridges now own bus 2; type-1 config
   cycles for the CardBus card are also claimed by pcie0 (firmware-configured)
   (config reads/writes can hit an unrelated device).
socket #127: secbus_reg=256 -> u_int8_t secbus=0, subbus_reg=257 -> u_int8_t subbus=1
socket #128: secbus_reg=258 -> u_int8_t secbus=2, subbus_reg=259 -> u_int8_t subbus=3

curr_bus_number=260 after 128 sockets: no >255 check exists;
socket #127 got secbus_reg=256 -> u_int8_t secbus=0: the very
'unconfigured' sentinel (secbus==0) that pccbb_pci.c:345 treats as
invalid -- re-triggers renumbering on resume/re-probe and aliases
the host bus (bus 0) for CardBus config cycles.
exit=0