still "Fatal trap 12" while booting 5.3-beta-3 on acer tm

Hi,

the laptop is still an Acer Travelmate TM291 (Centrino, 
"hotpluggable" DVD/CDRW-Combo, bg2200 WLAN).

Using
set hw.pci.enable_io_modes="0"I get the laptop to get past the 
PCI detection and get a Fatal trap 12 at or after USB detection.

I appended the last couple of lines from the console below.

Please advice, how I can get around this.

Regards,
Robert

----- output from boot -v -----
uhci0: [GIANT-LOCKED]
usb0: <Intel 82801DB (ICH4) 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 82801DB (ICH4) USB controller USB-B> port 
0x1600-0x161f at device 19.1 on pci0
uhci1: Reserved 0x20 bytes for rid 0x20 type 4 at 0x1600
$PIR: Fount IRQ 10 for link 0x63 from 5 10 11


Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address  = 0xe7e02
fault code             = supervior read, page not present
instruction pointer    = 0x8:0xc00e9d05
stack pointer          = 0x10:0xc10219ec
frame pointer          = 0x10:0xc10219ec
code segment           = base 0x0, limit 0xfffff, type 0x1b
                       = DPL 0, pres 1, def32 1, gran 1
processor eflags       = interrupt enabled, resume, IOPL = 0
current process        = 0 (swapper)
[thread 0]
Stopped at      0xc00e9d05:     cmpb    %cs:0x1(%esi),%bl
db> trace
kernbase(c0812ff4,c20,c07f2384,a0b,e9) at 0xc00e9d05
end(cb9d08c4,c4f6ec8b,81067540,ffffe5,e67f2400) at 0xc1021a44
db>