DF-3640: requires bnx(4) hardware. On such a system, after the
driver loads, read BGE_NVRAM_SWARB (dev.bnx.0 regs via kgdb or
pciconf): the GNT1 grant bit stays set forever because bnx_reset
never writes BGE_NVRAMSWARB_CLR1 (grep: 0 occurrences in
if_bnx.c; bge releases at if_bge.c:588).
===EVIDENCE===
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
		61 pci/if_bnx
NO_BROADCOM_DEVICE
vtnet0 lo0
sysctl: unknown oid 'hw.bnx'
MD5 (/usr/src/sys/dev/netif/bnx/if_bnx.c) = 49a18c4b7642b9b2ebd1d02ad11542e4
CLR1 count in bnx: 0
0
2585:	CSR_WRITE_4(sc, BGE_NVRAM_SWARB, BGE_NVRAMSWARB_SET1);
2587:		if (CSR_READ_4(sc, BGE_NVRAM_SWARB) & BGE_NVRAMSWARB_GNT1)
CLR1 count in bge: 1