Kurt Schreiner wrote (in the "opteron 246 system" thread):

I'm working on the Opteron 270 system, which also has a H8DCE mobo; I need it 
first. I don't know if it matters, but it seemed to before - the 270 and 246 
systems behaved differently...

 > On Sat, Aug 19, 2006 at 11:28:07AM +0200, Frank van der Linden wrote:

 > Hm, memory mappings: my ultra40 is ok, when I set "pci mem hole" to
 > "software". Changing this to "hardware" gives a "running system with
 > _verry_ slow disk access". I don't remember the name of the third
 > possibility to set "pci mem hole", but using that leads to a system
 > crashing during boot... Just another data point...
 > Chris, does your bios allow playing w/ "pci mem hole"?

Under the Northbridge config, in "Memory Configuration", there is a "hardware 
memory hold" setting. The default is enabled. I disabled it. The BIOS comments 
note that this is "ONLY supported by REV E0 processors and above", which I think 
isn't an issue for me, though I'm not entirely sure where to read the rev number...

Your 3.99.21 INSTALL_ACPI ISO booted just fine! Found the disks and everything. 
Install went OK (but didn't ask me to configure the network?)

Not surprisingly, booting GENERIC doesn't work very well - same as before, can't 
figure out the SATA (nForce) controllers.

When I boot the GENERIC_ACPI that's on the ISO, it freezes after  probing sysbeep0:

 > boot netbsd-GENERIC_ACPI
booting hd0a:netbsd-GENERIC_ACPI
7240512+860952+390256 [518304+330748]=0x9e91e8
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
     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 3.99.21 (GENERIC_ACPI) #1: Tue Jul  4 13:09:30 MEST 2006
         ks@isunopti:/u/NetBSD/arch/amd64/obj/sys/arch/amd64/compile/GENERIC_ACPI
total memory = 7087 MB
avail memory = 6824 MB
timecounter: Timecounters tick every 10.000 msec
timecounter: Timecounter "i8254" frequency 1193182 Hz quality 100
timecounter: selected timecounter "i8254" frequency 1193182 Hz quality 100
mainbus0 (root)
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Dual Core AMD Opteron(tm) Processor 270, 2000.12 MHz
cpu0: features: f7dbfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>
cpu0: features: f7dbfbff<PGE,MCA,CMOV,PAT,PSE36,MPC,NOX,MMXX,MMX>
cpu0: features: f7dbfbff<FXSR,SSE,SSE2,HTT,LONG,3DNOW2,3DNOW>
cpu0: calibrating local timer
cpu0: apic clock running at 199 MHz
cpu0: 16 page colors
cpu1 at mainbus0: apid 1 (application processor)
cpu1: not started
cpu2 at mainbus0: apid 2 (application processor)
cpu2: not started
cpu3 at mainbus0: apid 3 (application processor)
cpu3: not started
ioapic0 at mainbus0 apid 4 (I/O APIC)
ioapic0: pa 0xfec00000, version 11, 24 pins
ioapic1 at mainbus0 apid 5 (I/O APIC)
ioapic1: pa 0xdfefc000, version 11, 24 pins
acpi0 at mainbus0: Advanced Configuration and Power Interface
acpi0: fixed-feature power button present
timecounter: Timecounter "ACPI-Fast" frequency 3579545 Hz quality 1000
timecounter: selected timecounter "ACPI-Fast" frequency 3579545 Hz quality 1000
ACPI-Fast 24-bit timer
allocated pic ioapic0 type level pin 9 level 10 to cpu0 slot 16 idt entry 160
ACPI Object Type 'Processor' (0x0c) at acpi0 not configured
ACPI Object Type 'Processor' (0x0c) at acpi0 not configured
ACPI Object Type 'Processor' (0x0c) at acpi0 not configured
ACPI Object Type 'Processor' (0x0c) at acpi0 not configured
PNP0A03 [PCI/PCI-X Host Bridge] at acpi0 not configured
PNP0000 [AT Interrupt Controller] at acpi0 not configured
PNP0200 [AT DMA Controller] at acpi0 not configured
PNP0100 [AT Timer] at acpi0 not configured
PNP0B00 [AT Real-Time Clock] at acpi0 not configured
PNP0800 [AT-style speaker sound] at acpi0 not configured
PNP0C04 [Math Coprocessor] at acpi0 not configured
PNP0501 [16550A-compatible COM port] at acpi0 not configured
PNP0501 [16550A-compatible COM port] at acpi0 not configured
PNP0700 [PC standard floppy disk controller] at acpi0 not configured
PNP0400 [Standard LPT printer port] at acpi0 not configured
PNP0C02 [Plug and Play motherboard register resources] at acpi0 not configured
PNP0C02 [Plug and Play motherboard register resources] at acpi0 not configured
PNP0303 [IBM Enhanced (101/102-key, PS/2 mouse support)] at acpi0 not configured
PNP0C02 [Plug and Play motherboard register resources] at acpi0 not configured
PNP0C02 [Plug and Play motherboard register resources] at acpi0 not configured
PNP0C01 [System Board] at acpi0 not configured
PNP0A03 [PCI/PCI-X Host Bridge] at acpi0 not configured
PNP0C0C [ACPI power button device] at acpi0 not configured
PNP0C0F [PCI interrupt link device] at acpi0 not configured
pci0 at mainbus0 bus 0: configuration mode 1
pci0: i/o space, memory space enabled, rd/line, rd/mult, wr/inv ok
NVIDIA nForce4 Memory Controller (miscellaneous memory, revision 0xa3) at pci0 
dev 0 function 0 not configured
pcib0 at pci0 dev 1 function 0
pcib0: NVIDIA nForce4 PCI-ISA bridge (rev. 0xa3)
NVIDIA nForce4 SMBus (SMBus serial bus, revision 0xa2) at pci0 dev 1 function 1 
not configured
ohci0 at pci0 dev 2 function 0: NVIDIA nForce4 USB Host Controller (rev. 0xa2)
allocated pic ioapic0 type level pin 20 level 6 to cpu0 slot 9 idt entry 96
ohci0: interrupting at ioapic0 pin 20 (irq 9)
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 nForce4 USB2 Host Controller (rev. 0xa3)
allocated pic ioapic0 type level pin 21 level 6 to cpu0 slot 17 idt entry 97
ehci0: interrupting at ioapic0 pin 21 (irq 9)
ehci0: BIOS has given up ownership
ehci0: EHCI version 1.0
ehci0: companion controller, 4 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
auich0 at pci0 dev 4 function 0: nForce4 AC-97 Audio
allocated pic ioapic0 type level pin 22 level 11 to cpu0 slot 18 idt entry 176
auich0: interrupting at ioapic0 pin 22 (irq 9)
auich0: ac97: Avance Logic ALC650 codec; 20 bit DAC, 18 bit ADC, Realtek 3D
auich0: ac97: ext id 5c7<AC97_22,LDAC,SDAC,CDAC,SPDIF,DRA,VRA>
viaide0 at pci0 dev 6 function 0
viaide0: NVIDIA nForce4 IDE Controller (rev. 0xf2)
viaide0: bus-master DMA support present
viaide0: primary channel configured to compatibility mode
allocated pic ioapic0 type edge pin 14 level 6 to cpu0 slot 14 idt entry 98
viaide0: primary channel interrupting at ioapic0 pin 14 (irq 14)
atabus0 at viaide0 channel 0
viaide0: secondary channel configured to compatibility mode
allocated pic ioapic0 type edge pin 15 level 6 to cpu0 slot 15 idt entry 99
viaide0: secondary channel interrupting at ioapic0 pin 15 (irq 15)
atabus1 at viaide0 channel 1
viaide1 at pci0 dev 7 function 0
viaide1: NVIDIA nForce4 Serial ATA Controller (rev. 0xf3)
viaide1: bus-master DMA support present
viaide1: primary channel wired to native-PCI mode
allocated pic ioapic0 type level pin 20 level 6 to cpu0 slot 9 idt entry 96
viaide1: using ioapic0 pin 20 (irq 9) for native-PCI interrupt
atabus2 at viaide1 channel 0
viaide1: secondary channel wired to native-PCI mode
atabus3 at viaide1 channel 1
viaide2 at pci0 dev 8 function 0
viaide2: NVIDIA nForce4 Serial ATA Controller (rev. 0xf3)
viaide2: bus-master DMA support present
viaide2: primary channel wired to native-PCI mode
allocated pic ioapic0 type level pin 21 level 6 to cpu0 slot 17 idt entry 97
viaide2: using ioapic0 pin 21 (irq 5) for native-PCI interrupt
atabus4 at viaide2 channel 0
viaide2: secondary channel wired to native-PCI mode
atabus5 at viaide2 channel 1
ppb0 at pci0 dev 9 function 0: NVIDIA nForce4 PCI Host Bridge (rev. 0xa2)
pci1 at ppb0 bus 3
pci1: i/o space, memory space enabled
nfe0 at pci0 dev 10 function 0allocated pic ioapic0 type level pin 22 level 7 to 
cpu0 slot 18 idt entry 112
: ioapic0 pin 22 (irq 11), address 00:30:48:57:7f:b8
makphy0 at nfe0 phy 1: Marvell 88E1111 Gigabit PHY, rev. 2
makphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto
ppb1 at pci0 dev 13 function 0: NVIDIA nForce4 PCIe Host Bridge (rev. 0xa3)
pci2 at ppb1 bus 2
pci2: memory space enabled, rd/line, wr/inv ok
ppb2 at pci0 dev 14 function 0: NVIDIA nForce4 PCIe Host Bridge (rev. 0xa3)
pci3 at ppb2 bus 1
pci3: i/o space, memory space enabled, rd/line, wr/inv ok
vga0 at pci3 dev 0 function 0: NVIDIA GeForce 6200TC (rev. 0xa1)
vga0: WARNING: ignoring 64-bit BAR @ 0x14
vga0: WARNING: ignoring 64-bit BAR @ 0x1c
wsdisplay0 at vga0 kbdmux 1
wsmux1: connecting to wsdisplay0
pchb0 at pci0 dev 24 function 0
pchb0: Advanced Micro Devices AMD64 HyperTransport configuration (rev. 0x00)
pchb1 at pci0 dev 24 function 1
pchb1: Advanced Micro Devices AMD64 Address Map configuration (rev. 0x00)
pchb2 at pci0 dev 24 function 2
pchb2: Advanced Micro Devices AMD64 DRAM configuration (rev. 0x00)
pchb3 at pci0 dev 24 function 3
pchb3: Advanced Micro Devices AMD64 Miscellaneous configuration (rev. 0x00)
pchb4 at pci0 dev 25 function 0
pchb4: Advanced Micro Devices AMD64 HyperTransport configuration (rev. 0x00)
pchb5 at pci0 dev 25 function 1
pchb5: Advanced Micro Devices AMD64 Address Map configuration (rev. 0x00)
pchb6 at pci0 dev 25 function 2
pchb6: Advanced Micro Devices AMD64 DRAM configuration (rev. 0x00)
pchb7 at pci0 dev 25 function 3
pchb7: Advanced Micro Devices AMD64 Miscellaneous configuration (rev. 0x00)
isa0 at pcib0
lpt0 at isa0 port 0x378-0x37b irq 7
allocated pic ioapic0 type edge pin 7 level 9 to cpu0 slot 7 idt entry 144
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
com0: console
allocated pic ioapic0 type edge pin 4 level 13 to cpu0 slot 4 idt entry 208
com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
allocated pic ioapic0 type edge pin 3 level 13 to cpu0 slot 3 idt entry 209
pckbc0 at isa0 port 0x60-0x64
pckbd0 at pckbc0 (kbd slot)
allocated pic ioapic0 type edge pin 1 level 9 to cpu0 slot 1 idt entry 145
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0 mux 1
wskbd0: connecting to wsdisplay0
attimer0 at isa0 port 0x40-0x43: AT Timer
pcppi0 at isa0 port 0x61
midi0 at pcppi0: PC speaker (CPU-intensive output)
sysbeep0 at pcppi0

and eventually resets. Looks like it finds the viaiade controllers OK, but can't 
find any disks.

I tried, just to be sure, to enable the PCI memory hole - doesn't work any better.

I'll try another kernel now. I have lots.