hang during kldload if_bwn

Hi folks,

I have a PowerBook G4 with an Airport Extreme card (bwi/bwn, can use
either one), and found if I don't have the exact correct firmware it
hangs.  Here's a snippet of WITNESS before it hangs:

siba_bwn0: <Broadcom BCM4318 802.11b/g Wireless> mem
0xa0004000-0xa0005fff irq 52 at device 17.0 on pci1 bwn0 on siba_bwn0
bwn0: bwn_attach_core: forcing 2GHz only; no dual-band support for PHY
bwn0: WLAN (chipid 0x4318 rev 9) PHY (analog 3 type 2 rev 7) RADIO
(manuf 0x17f ver 0x2050 rev 8) bwn0: DMA (32 bits)
wlan0: Ethernet address: 00:14:51:7d:60:39
bwn0: ucode fw: ucode5
Sleeping on "fwload" with the following non-sleepable locks held:
exclusive sleep mutex bwn0 (network driver) r = 0 (0xd2e57004) locked
_at_ /usr/src/sys/modules/bwn/../../dev/bwn/if_bwn.c:814 stack backtrace:
#0 0x50fd64 at witness_warn+0x2c0
#1 0x49ef0c at _sleep+0xc8
#2 0x4e2e10 at firmware_get+0x120
#3 0xd2d0a6e4 at bwn_fw_get+0xe4
#4 0xd2d1057c at bwn_fw_gets+0x1ac
#5 0xd2d13130 at bwn_core_init+0x28c
#6 0xd2d151f0 at bwn_init+0x310
#7 0xd2d15408 at bwn_parent+0x80
#8 0xd2da794c at parent_updown+0x1c
#9 0x4fe6dc at taskqueue_run_locked+0x178
#10 0x4ff468 at taskqueue_thread_loop+0xa8
#11 0x44c99c at fork_exit+0xc0
#12 0x8229dc at fork_trampoline+0xc
bwn_v4_ucode5: could not load firmware image, error 2
bwn0: the fw file(bwn_v4_ucode5) not found
bwn0: ucode fw: ucode5
Sleeping on "fwload" with the following non-sleepable locks held:
exclusive sleep mutex bwn0 (network driver) r = 0 (0xd2e57004) locked
_at_ /usr/src/sys/modules/bwn/../../dev/bwn/if_bwn.c:814 stack backtrace:
#0 0x50fd64 at witness_warn+0x2c0
#1 0x49ef0c at _sleep+0xc8
#2 0x4e2e10 at firmware_get+0x120
#3 0xd2d0a6e4 at bwn_fw_get+0xe4
#4 0xd2d1057c at bwn_fw_gets+0x1ac
#5 0xd2d13130 at bwn_core_init+0x28c
#6 0xd2d151f0 at bwn_init+0x310
#7 0xd2d15408 at bwn_parent+0x80
#8 0xd2da794c at parent_updown+0x1c
#9 0x4fe6dc at taskqueue_run_locked+0x178
#10 0x4ff468 at taskqueue_thread_loop+0xa8
#11 0x44c99c at fork_exit+0xc0
#12 0x8229dc at fork_trampoline+0xc
bwn-open_v4_ucode5: could not load firmware image, error 2
bwn0: the fw file(bwn-open_v4_ucode5) not found


Creating a symlink in /boot/modules of bwn_v4_ucode5.ko ->
bwn_v4_ucode.ko makes it not hang, but it still triggers WITNESS.

- Justin