I've recently gotten a new machine running NetBSD/i386,
and with a current GENERIC kernel I'm getting a panic during
initial kernel configuration:

panic: pci_make_tag: bad request

does anyone have any tips for what could be wrong?
the traceback looks something like:

AcpiOsReadPciConfiguration
get_bus_number
AcpiOsDerivePciId
[...lots of stack levels, but it's inside acpi_attach at least,
if there are specific details that would be useful I can probably
transcribe them...]

booting the GENERIC.NOACPI kernel works, here's the dmesg after boot:

Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
     2006, 2007
     The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
     The Regents of the University of California.  All rights reserved.

NetBSD 4.99.29 (GENERIC.NOACPI) #2: Mon Aug 20 14:41:29 CEST 2007
 	root@inngang:/usr/obj/sys/arch/i386/compile/GENERIC.NOACPI
total memory = 1919 MB
rbus: rbus_min_start set to 0x80000000
avail memory = 1875 MB
timecounter: Timecounters tick every 10.000 msec
timecounter: Timecounter "i8254" frequency 1193182 Hz quality 100
BIOS32 rev. 0 found at 0xf0010
mainbus0 (root)
cpu0 at mainbus0: (uniprocessor)
cpu0: AMD Athlon X2 or Athlon 64 X2 (686-class), 2310.50 MHz, id 0x60fb1
cpu0: features ffdbfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>
cpu0: features ffdbfbff<PGE,MCA,CMOV,PAT,PSE36,MPC,NOX,MMXX,MMX>
cpu0: features ffdbfbff<FXSR,SSE,SSE2,RDTSCP,HTT,LONG,3DNOW2,3DNOW>
cpu0: features2 2001<SSE3>
cpu0: "AMD Athlon(tm) 64 X2 Dual Core Processor 4400+"
cpu0: I-cache 64 KB 64B/line 2-way, D-cache 64 KB 64B/line 2-way
cpu0: L2 cache 512 KB 64B/line 16-way
cpu0: ITLB 32 4 KB entries fully associative, 8 4 MB entries fully associative
cpu0: DTLB 32 4 KB entries fully associative, 8 4 MB entries fully associative
cpu0: AMD Power Management features: 7f<STC,TM,TTP,VID,FID,TS>
cpu0: AMD PowerNow! Technology 2300 MHz
cpu0: available frequencies (Mhz): 1000 1800 2000 2200 2300
cpu0: 8 page colors
pci0 at mainbus0 bus 0: configuration mode 1
pci0: i/o space, memory space enabled, rd/line, rd/mult, wr/inv ok
NVIDIA product 0x03ea (RAM memory, revision 0xa1) at pci0 dev 0 function 0 not configured
pcib0 at pci0 dev 1 function 0
pcib0: NVIDIA nForce MCP61 PCI-ISA Bridge (rev. 0xa2)
NVIDIA nForce MCP61 SMBus Controller (SMBus serial bus, revision 0xa2) at pci0 dev 1 function 1 not configured
NVIDIA product 0x03f5 (RAM memory, revision 0xa2) at pci0 dev 1 function 2 not configured
ohci0 at pci0 dev 2 function 0: NVIDIA product 0x03f1 (rev. 0xa2)
ohci0: interrupting at irq 5
ohci0: OHCI version 1.0, legacy support
usb0 at ohci0: USB revision 1.0
uhub0 at usb0
uhub0: NVIDIA OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 10 ports with 10 removable, self powered
ehci0 at pci0 dev 2 function 1: NVIDIA product 0x03f2 (rev. 0xa2)
ehci0: interrupting at irq 10
ehci0: BIOS has given up ownership
ehci0: EHCI version 1.0
ehci0: companion controller, 10 ports each: ohci0
usb1 at ehci0: USB revision 2.0
uhub1 at usb1
uhub1: NVIDIA EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
uhub1: 10 ports with 10 removable, self powered
ppb0 at pci0 dev 4 function 0: NVIDIA product 0x03f3 (rev. 0xa1)
pci1 at ppb0 bus 1
pci1: i/o space, memory space enabled
fxp0 at pci1 dev 8 function 0: i82559 Ethernet, rev 8
fxp0: interrupting at irq 11
fxp0: Ethernet address 00:90:27:dc:0c:98
inphy0 at fxp0 phy 1: i82555 10/100 media interface, rev. 4
inphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
azalia0 at pci0 dev 5 function 0: Generic High Definition Audio Controller
azalia0: interrupting at irq 11
azalia0: host: 0x10de/0x03f0 (rev. 162)
azalia0: host: High Definition Audio rev. 1.0
viaide0 at pci0 dev 6 function 0
viaide0: NVIDIA MCP61 IDE Controller (rev. 0xa2)
viaide0: bus-master DMA support present
viaide0: primary channel configured to compatibility mode
viaide0: primary channel interrupting at irq 14
atabus0 at viaide0 channel 0
viaide0: secondary channel configured to compatibility mode
viaide0: secondary channel ignored (disabled)
nfe0 at pci0 dev 7 function 0: NVIDIA nForce MCP61 Gigabit Ethernet Controller (rev. 0xa2)
nfe0: interrupting at irq 5
nfe0: Ethernet address f4:49:e1:8f:13:00
rgephy0 at nfe0 phy 1: RTL8169S/8110S 1000BASE-T media interface, rev. 2
rgephy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 1000baseT-FDX, auto
viaide1 at pci0 dev 8 function 0
viaide1: NVIDIA MCP61 Serial ATA Controller (rev. 0xa2)
viaide1: bus-master DMA support present
viaide1: primary channel wired to native-PCI mode
viaide1: using irq 10 for native-PCI interrupt
atabus1 at viaide1 channel 0
viaide1: secondary channel wired to native-PCI mode
atabus2 at viaide1 channel 1
viaide2 at pci0 dev 8 function 1
viaide2: NVIDIA MCP61 Serial ATA Controller (rev. 0xa2)
viaide2: bus-master DMA support present
viaide2: primary channel wired to native-PCI mode
viaide2: using irq 10 for native-PCI interrupt
atabus3 at viaide2 channel 0
viaide2: secondary channel wired to native-PCI mode
atabus4 at viaide2 channel 1
ppb1 at pci0 dev 9 function 0: NVIDIA nForce MCP61 PCI-PCI Bridge (rev. 0xa2)
pci2 at ppb1 bus 2
pci2: no spaces enabled!
ppb2 at pci0 dev 11 function 0: NVIDIA nForce MCP61 PCI-PCI Bridge (rev. 0xa2)
pci3 at ppb2 bus 3
pci3: no spaces enabled!
ppb3 at pci0 dev 12 function 0: NVIDIA nForce MCP61 PCI-PCI Bridge (rev. 0xa2)
pci4 at ppb3 bus 4
pci4: no spaces enabled!
vga1 at pci0 dev 13 function 0: NVIDIA product 0x03d0 (rev. 0xa2)
vga1: WARNING: ignoring 64-bit BAR @ 0x14
vga1: WARNING: ignoring 64-bit BAR @ 0x1c
wsdisplay0 at vga1 kbdmux 1: console (80x25, vt100 emulation)
wsmux1: connecting to wsdisplay0
direct rendering for vga1 unsupported
pchb0 at pci0 dev 24 function 0
pchb0: Advanced Micro Devices K8 AMD64 HyperTransport configuration (rev. 0x00)
pchb1 at pci0 dev 24 function 1
pchb1: Advanced Micro Devices K8 AMD64 Address Map configuration (rev. 0x00)
pchb2 at pci0 dev 24 function 2
pchb2: Advanced Micro Devices K8 AMD64 DRAM configuration (rev. 0x00)
pchb3 at pci0 dev 24 function 3
pchb3: Advanced Micro Devices K8 AMD64 Miscellaneous configuration (rev. 0x00)
isa0 at pcib0
lpt0 at isa0 port 0x378-0x37b irq 7
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
pckbc0 at isa0 port 0x60-0x64
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pms0 at pckbc0 (aux slot)
pckbc0: using irq 12 for aux slot
wsmouse0 at pms0 mux 0
attimer0 at isa0 port 0x40-0x43: AT Timer
pcppi0 at isa0 port 0x61
midi0 at pcppi0: PC speaker (CPU-intensive output)
sysbeep0 at pcppi0
isapnp0 at isa0 port 0x279: ISA Plug 'n Play device support
npx0 at isa0 port 0xf0-0xff
npx0: reported by CPUID; using exception 16
pcppi0: attached to attimer0
isapnp0: no ISA Plug 'n Play devices found
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0
azalia0: codec[0]: Realtek ALC888 (rev. 0.1)
azalia0: codec[0]: High Definition Audio rev. 1.0
azalia0: playback: max channels=8, encodings=1<PCM>
azalia0: playback: PCM formats=e0560<24bit,20bit,16bit,192kHz,96kHz,48kHz,44.1kHz>
azalia0: recording: max channels=4, encodings=1<PCM>
azalia0: recording: PCM formats=60160<20bit,16bit,96kHz,48kHz,44.1kHz>
audio0 at azalia0: full duplex, independent
Kernelized RAIDframe activated
viaide1 port 0: device present, speed: 3.0Gb/s
viaide1 port 1: device present, speed: 1.5Gb/s
viaide2 port 0: device present, speed: 1.5Gb/s
wd0 at atabus1 drive 0: <WDC WD2500JS-00NCB1>
wd0: drive supports 16-sector PIO transfers, LBA48 addressing
wd0: 232 GB, 484521 cyl, 16 head, 63 sec, 512 bytes/sect x 488397168 sectors
wd0: 32-bit data port
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
wd0(viaide1:0:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using DMA)
atapibus0 at atabus2: 2 targets
cd0 at atapibus0 drive 0: <TSSTcorpCD/DVDW SH-S183A, , SB02> cdrom removable
cd0: 32-bit data port
cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 2 (Ultra/33)
cd0(viaide1:1:0): using PIO mode 4, Ultra-DMA mode 2 (Ultra/33) (using DMA)
wd1 at atabus3 drive 0: <Maxtor 6Y120M0>
wd1: drive supports 16-sector PIO transfers, LBA addressing
wd1: 114 GB, 238216 cyl, 16 head, 63 sec, 512 bytes/sect x 240121728 sectors
wd1: 32-bit data port
wd1: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 6 (Ultra/133)
wd1(viaide2:0:0): using PIO mode 4, Ultra-DMA mode 6 (Ultra/133) (using DMA)
findroot: unable to read block 266245176
boot device: wd0
root on wd0a dumps on wd0b
uhidev0 at uhub0 port 3 configuration 1 interface 0
uhidev0: Logitech USB Receiver, rev 1.10/17.21, addr 2, iclass 3/1
ukbd0 at uhidev0
root file system type: ffs
wskbd1 at ukbd0 mux 1
wskbd1: connecting to wsdisplay0
uhidev1 at uhub0 port 3 configuration 1 interface 1
uhidev1: Logitech USB Receiver, rev 1.10/17.21, addr 2, iclass 3/1
uhidev1: 4 report ids
ums0 at uhidev1 reportid 1: 16 buttons and Z dir.
wsmouse1 at ums0 mux 0
uhid0 at uhidev1 reportid 2: input=2, output=0, feature=0
uhid1 at uhidev1 reportid 3: input=1, output=0, feature=0
uhid2 at uhidev1 reportid 4: input=3, output=0, feature=0
wsdisplay0: screen 1 added (80x25, vt100 emulation)
wsdisplay0: screen 2 added (80x25, vt100 emulation)
wsdisplay0: screen 3 added (80x25, vt100 emulation)
wsdisplay0: screen 4 added (80x25, vt100 emulation)

>Fix:
 	booting GENERIC.NOACPI is a workaround for now.