usb device detection fails during load; works afterwards

[Peter de Rooij]

FreeBSD 6.0 Generic on i386.
Symptoms:
- during load, no USB devices are detected in most cases.
   (dmesg for verbose boot below)
   Randomly (?) USB detection does work at boot and detects all
   attached devices; say 1 in 10 times.
- after load, USB device detection does work fine.
- whenever at-load-detection does not work, there is a LONG pause
   (half a minute or so) right after detection of keyboard, just before
   the unable to allocate IRQ message for psm0.

dmesg extract:
============================================================
Copyright (c) 1992-2005 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
	The Regents of the University of California. All rights reserved.
FreeBSD 6.0-RELEASE #0: Thu Nov  3 09:36:13 UTC 2005
     root at x64.samsco.home:/usr/obj/usr/src/sys/GENERIC
:
:
CPU: Intel(R) Pentium(R) 4 CPU 2.80GHz (2793.01-MHz 686-class CPU)
   Origin = "GenuineIntel"  Id = 0xf34  Stepping = 4
 
Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
   Features2=0x441d<SSE3,RSVD2,MON,DS_CPL,CNTX-ID,<b14>>
:
:
uhci0: <Intel 82801EB (ICH5) USB controller USB-A> port 0x1440-0x145f 
irq 16 at device 29.0 on pci0
uhci0: Reserved 0x20 bytes for rid 0x20 type 4 at 0x1440
uhci0: [GIANT-LOCKED]
usb0: <Intel 82801EB (ICH5) USB controller USB-A> on uhci0
usb0: USB revision 1.0
uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
uhci1: <Intel 82801EB (ICH5) USB controller USB-B> port 0x1460-0x147f 
irq 19 at device 29.1 on pci0
uhci1: Reserved 0x20 bytes for rid 0x20 type 4 at 0x1460
uhci1: [GIANT-LOCKED]
usb1: <Intel 82801EB (ICH5) USB controller USB-B> on uhci1
usb1: USB revision 1.0
uhub1: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub1: 2 ports with 2 removable, self powered
uhci2: <Intel 82801EB (ICH5) USB controller USB-C> port 0x1480-0x149f 
irq 18 at device 29.2 on pci0
uhci2: Reserved 0x20 bytes for rid 0x20 type 4 at 0x1480
uhci2: [GIANT-LOCKED]
usb2: <Intel 82801EB (ICH5) USB controller USB-C> on uhci2
usb2: USB revision 1.0
uhub2: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub2: 2 ports with 2 removable, self powered
ehci0: <EHCI (generic) USB 2.0 controller> mem 0xfc480000-0xfc4803ff irq 
23 at device 29.7 on pci0
ehci0: Reserved 0x400 bytes for rid 0x10 type 3 at 0xfc480000
ehci0: [GIANT-LOCKED]
usb3: EHCI version 1.0
usb3: wrong number of companions (4 != 3)
usb3: companion controllers, 2 ports each: usb0 usb1 usb2
usb3: <EHCI (generic) USB 2.0 controller> on ehci0
usb3: USB revision 2.0
uhub3: Intel EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
uhub3: 8 ports with 8 removable, self powered
:
:
pnp_identify: Trying Read_Port at 203
pnp_identify: Trying Read_Port at 243
pnp_identify: Trying Read_Port at 283
pnp_identify: Trying Read_Port at 2c3
pnp_identify: Trying Read_Port at 303
pnp_identify: Trying Read_Port at 343
pnp_identify: Trying Read_Port at 383
pnp_identify: Trying Read_Port at 3c3
PNP Identify complete
pnpbios: error 0/82 getting device count/size limit
unknown: status reg test failed ff
unknown: status reg test failed ff
unknown: status reg test failed ff
unknown: status reg test failed ff
unknown: status reg test failed ff
unknown: status reg test failed ff
sc: sc0 already exists; skipping it
vga: vga0 already exists; skipping it
isa_probe_children: disabling PnP devices
isa_probe_children: probing non-PnP devices
pmtimer0 on isa0
adv0: not probed (disabled)
aha0: not probed (disabled)
aic0: not probed (disabled)
atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
atkbd: the current kbd controller command byte 0047
atkbd: keyboard ID 0x41ab (2)
kbd0 at atkbd0
kbd0: atkbd0, AT 101/102 (2), config:0x0, flags:0x3d0000
atkbd0: [GIANT-LOCKED]
psm0: unable to allocate IRQ
bt0: not probed (disabled)
cs0: not probed (disabled)
ed0: not probed (disabled)
fdc0: ic_type 90 part_id 80
fdc0: <Enhanced floppy controller> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 
on isa0
fdc0: ic_type 90 part_id 80
fdc0: [MPSAFE]
fdc0: [FAST]
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
fe0: not probed (disabled)
ie0: not probed (disabled)
lnc0: not probed (disabled)
ppc0: parallel port found at 0x378
ppc0: using extended I/O port range
ppc0: ECP SPP ECP+EPP SPP
ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0
ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode
ppc0: FIFO with 16/16/13 bytes threshold
ppbus0: <Parallel port bus> on ppc0
plip0: <PLIP network interface> on ppbus0
plip0: bpf attached
lpt0: <Printer> on ppbus0
lpt0: Interrupt-driven port
ppi0: <Parallel I/O> on ppbus0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
sc0: fb0, kbd0, terminal emulator: sc (syscons terminal)
sio0: irq maps: 0x4481 0x4491 0x4481 0x4481
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A
sio1: configured irq 3 not in bitmap of probed irqs 0
sio1: port may not be enabled
sio1: irq maps: 0x4481 0x4481 0x4481 0x4481
sio1: probe failed test(s): 0 1 2 4 6 7 9
sio1 failed to probe at port 0x2f8-0x2ff irq 3 on isa0
sio2: not probed (disabled)
sio3: not probed (disabled)
sn0: not probed (disabled)
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
vt0: not probed (disabled)
isa_probe_children: probing PnP devices
Device configuration finished.
procfs registered
:
:
Trying to mount root from ufs:/dev/ad0s2a
start_init: trying /sbin/init
ums0: Logitech USB-PS/2 Optical Mouse, rev 2.00/11.10, addr 2, iclass 3/1
ums0: 3 buttons and Z dir.
umass0: vendor 0x0930 USB Flash Memory, rev 2.00/1.00, addr 2
umass0:0:0:-1: Attached to scbus0
pass0 at umass-sim0 bus 0 target 0 lun 0
pass0: < USB Flash Memory 1.00> Removable Direct Access SCSI-2 device
pass0: Serial Number \^_
pass0: 40.000MB/s transfers
GEOM: new disk da0
da0 at umass-sim0 bus 0 target 0 lun 0
da0: < USB Flash Memory 1.00> Removable Direct Access SCSI-2 device
da0: Serial Number \^_
da0: 40.000MB/s transfers
da0: 489MB (1001472 512 byte sectors: 64H 32S/T 489C)
============================================================
The ums and da0 devices were inserted after logging in (and worked 
fine).  The printer is also USB, and if I power-cycle it, it shows as
ulpt0 and unlpt0.
(Let me know if I snipped too much above -- cannot imagine:-)

I tried the following, with no results
- I have added usbd_load="YES" in loader.conf.  And ums_load="YES".
- I removed a device hint for psm0 in device.hints (I have a USB mouse)
- asked this question in freebsd-questions (minus some details)

What can I do to force/fix detection at load?
Unplugging and plugging my mouse at boot to get it to work is a bit 
annoying.

Cheers, Peter