Disassembling/Debugging the PC's BIOS?

I have a normal pc desktop machine with a msi k8t neo-v motherboard
which utilizes an AMI BIOS. I have a pci video card in an expansion
slot. On bootup POST, the BIOS complains about a routing table error on
device 0:05:00 which pionts to my video card (the only PCI device in an
expansion slot). This motherboard does not have onboard video so I need
this video card in order to see anything (as I do not have any
backups). This video card works flawlessly in another machine
(different mobo/chipset/bios). I have done some searching and it seems
I need to look for a "pnp os" setting in my BIOS; none exists (or the
the mobo manufacturer has conveniently removed the ability to alter
this setting as a lot of them do to a stock BIOS).

So I've come to the point where I want to disassembly/debug my BIOS to
see what the exact error is. I can use dos debug to find the location
of the '$PIR' signature of the routing table and maybe will only have
to analyze the data and this will show what the inconsistency/error is.
Otherwise I need to do some really-involved disassembly/debugging.

The video card still works, however very slowly. It's like it's
"painting" row by row....very obvious to the human eye. CPU utilization
runs up to 90% for a simple act like scrolling a ms-windows notepad
window (and takes a couple of seconds). The card itself is a 5volt PCI
ATI Rage Mobility card (mobo supports 3.3 & 5 and AGP up to 3.0).

I've reset CMOS, removed/reinstalled battery, disconnect power chord
from psu, disconnect all connections to the mobo including the atx PSU
connector, reseated the video card in all slots, removed/reinstalled
the cpu (which isan  AMD Athlon 64 @ 2.0Ghz, 200MHz HTT x4 = 800MHz
FSB), tried different memory (current is 512MB ddr400 [200Mhz bus], and
even booted up with only memory, cpu, psu, and video card hooked up and
still same error.

Any tips/pointers?

jonfaquit@yahoo.com wrote:
 > The card itself is a 5volt PCI
> ATI Rage Mobility card (mobo supports 3.3 & 5 and AGP up to 3.0).
> 

I too have had problems with ATI PCI video in a Compaq 3000 server
when installed with certain other cards; in the 3000 (PII EISA version)
the BIOS will hang during 'pci auto config' (see my old posts
in 'alt.sys.pc-clone.compaq.servers' regarding 'pci auto config').
This is most unfortunate since Compaq's Remote Insight products
use the RAGE 3D chipset and are supported boards for this platform.

I would be very interested in ongoing efforts to RE offending BIOS
code; perhaps these projects could be tackled by a team of willing
masochists.

Regards,

Michael Grigoni
Cybertheque Museum

jonfaquit@yahoo.com wrote:

> I have a normal pc desktop machine with a msi k8t neo-v motherboard
> which utilizes an AMI BIOS. I have a pci video card in an expansion
> slot. On bootup POST, the BIOS complains about a routing table error on
> device 0:05:00 which pionts to my video card (the only PCI device in an
> expansion slot). This motherboard does not have onboard video so I need
> this video card in order to see anything (as I do not have any
> backups). This video card works flawlessly in another machine
> (different mobo/chipset/bios). I have done some searching and it seems
> I need to look for a "pnp os" setting in my BIOS; none exists (or the
> the mobo manufacturer has conveniently removed the ability to alter
> this setting as a lot of them do to a stock BIOS).
> 
> So I've come to the point where I want to disassembly/debug my BIOS to
> see what the exact error is. I can use dos debug to find the location
> of the '$PIR' signature of the routing table and maybe will only have
> to analyze the data and this will show what the inconsistency/error is.
> Otherwise I need to do some really-involved disassembly/debugging.
> 
> The video card still works, however very slowly. It's like it's
> "painting" row by row....very obvious to the human eye. CPU utilization
> runs up to 90% for a simple act like scrolling a ms-windows notepad
> window (and takes a couple of seconds). The card itself is a 5volt PCI
> ATI Rage Mobility card (mobo supports 3.3 & 5 and AGP up to 3.0).
> 
> I've reset CMOS, removed/reinstalled battery, disconnect power chord
> from psu, disconnect all connections to the mobo including the atx PSU
> connector, reseated the video card in all slots, removed/reinstalled
> the cpu (which isan  AMD Athlon 64 @ 2.0Ghz, 200MHz HTT x4 = 800MHz
> FSB), tried different memory (current is 512MB ddr400 [200Mhz bus], and
> even booted up with only memory, cpu, psu, and video card hooked up and
> still same error.
> 
> Any tips/pointers?
The BIOS has problems assigning interrupts to the Board. Have you tried the
VGA board in other slots? (Ok. you had, overread it)  It may be that the
VGA board has faulty PCI configuration space and it's not the Mobo's fault.
Check the traces on the PCB, which lead to the PCI- INTA, INTB, INTC, INTD
contacts. If more then INTA is used (I.e, boards uses more than one
interrupt, which is quite uncommon these days) it may get difficult. IIRC 
"PnP" refers to legacy ISA PnP. PCI is plug-and-play by  default. 
Try to use an AGP board in addition to the PCI board. Start someting like
Knoppix (Linux on a DVD) and diagnose the PCI bus using lspci.

But what if this board works correctly on another computer? Would that
still be a faulty PCI config space? At the moment I'm running Debian as
video as Linux handles the video problem/setup better than windows.
It's still evident that there's a problem however.

heres some lspci -vvv

# lspci -vvv -s 0:05.0
0000:00:05.0 VGA compatible controller: ATI Technologies Inc Rage
Mobility P/M AGP 2x (rev 64) (prog-if 00 [VGA])
        Subsystem: ATI Technologies Inc Rage Mobility P/M AGP 2x
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping+ SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium
>TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 64 (2000ns min), Cache Line Size: 0x10 (64 bytes)
        Interrupt: pin A routed to IRQ 0
        Region 0: Memory at fd000000 (32-bit, non-prefetchable)
[size=16M]
        Region 1: I/O ports at e800 [size=256]
        Region 2: Memory at febff000 (32-bit, non-prefetchable)
[size=4K]
        Expansion ROM at febc0000 [disabled] [size=128K]
        Capabilities: [50] AGP version 1.0
                Status: RQ=256 Iso- ArqSz=0 Cal=0 SBA+ ITACoh- GART64-
HTrans- 64bit- FW- AGP3- Rate=x1,x2
                Command: RQ=1 ArqSz=0 Cal=0 SBA- AGP- GART64- 64bit-
FW- Rate=<none>
        Capabilities: [5c] Power Management version 1
                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA
PME(D0-,D1-,D2-,D3hot-,D3cold-)

jonfaquit@yahoo.com wrote:
> (different mobo/chipset/bios). I have done some searching and it seems
> I need to look for a "pnp os" setting in my BIOS; none exists (or the
> the mobo manufacturer has conveniently removed the ability to alter

Get the OEM customization utility for your motherboard BIOS and see if
you can simply re-enable the setting, if it exists.

Only thing I've found is a program called AMISETUP that does not work
(as it is unable to recognize my BIOS).

jonfaquit wrote:
> Only thing I've found is a program called AMISETUP that does not work
> (as it is unable to recognize my BIOS).

If you have an American Megatrends BIOS, you need AMIBCP. AMISETUP is
an ancient, ANCIENT utility that simply edits CMOS settings. AMIBCP
works on a BIOS dump and edits the menu structures in it.

ok, I'll look for it.

Well, I found AMIBCP but all versions of it crash under
win2k/winxp/winxp64 and the DOS version tells me the checksum is bad
for the particular BIOS image from MSI. The crash occurs in ntdll so I
will try this on another system.

It seems BIOS editing/modding tools are all out of date. The latest
programs are all prior to 2003.

Well, I analyzed my IRQ table. Based on my understanding, there's an
error in the table because the BIOS doesn't include an entry for bus 0,
device 5?

This is the table:
(microsoft spec: http://www.microsoft.com/whdc/archive/pciirq.mspx)

00: 24 50 49 52 00 01 D0 00-00 88 00 00 06 11 27 32   $PIR..........'2
10: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 47   ...............G
20: 00 08 01 F8 DC 02 F8 DC-00 00 00 00 00 00 00 00   ................
30: 00 88 00 00 00 00 00 00-03 F8 DC 00 00 00 00 00   ................
40: 00 80 01 F8 DC 02 F8 DC-03 F8 DC 05 F8 DC 00 00   ................
50: 00 78 02 F8 DC 03 F8 DC-05 F8 DC 01 F8 DC 00 00   .x..............
60: 00 40 01 F8 DC 02 F8 DC-03 F8 DC 05 F8 DC 01 00   .@..............
70: 00 48 02 F8 DC 03 F8 DC-05 F8 DC 01 F8 DC 02 00   .H..............
80: 00 50 03 F8 DC 05 F8 DC-01 F8 DC 02 F8 DC 03 00   .P..............
90: 00 58 05 F8 DC 01 F8 DC-02 F8 DC 03 F8 DC 04 00   .X..............
A0: 00 60 02 F8 DC 03 F8 DC-05 F8 DC 01 F8 DC 05 00   .`..............
B0: 00 70 02 F8 DC 03 F8 DC-05 F8 DC 01 F8 DC 05 00   .p..............
C0: 00 90 03 F8 DC 05 F8 DC-01 F8 DC 02 F8 DC 00 00   ................

--Table---------
0x00 - 03: signature = '$PIR'
0x04 - 05: version = 1.0
0x06 - 07: size = 0xD0 (bytes 00->CF)
0x20 - 0x2F: first slot entry (slots start at '1' for you 0-based
thinkers)
0x30 - 0x3F: second slot entry
...
0xC0 - 0xCF: last slot entry, in my case the 11th slot entry

--Slot Entry (0x00-0x0F)----------
0x00: bus number
0x01: dev number (in upper five bits...readable would be byte
shift-right 3)
0x02: link value for INTA# pci-connector pin
0x03-0x04: irq bitmap for INTA#
..
0x0C-0x0D: irq bitmap for INTD#
0x0E: slot number (0=system, non-zero = expansion slot number)


So if I'm looking for device 5, that would be byte 0x01 shifted-right 3
bits should equal 5 (or 5 shift-left 3 should equal (slot_entry_byte_01
& F8) == 0x28).

Problem is, there is none that match a device number of 5! Is that the
error? Where is the device number of 05 coming from? I thought device
number specifies the pci-bus's 'slot' (which is not necessarily an
expansion slot). The expansion slot I have the card in right now is #2.
Based on byte 0x7E being 2, this is the system 'slot' the card is
using. It has a device number "byte" of 0x48 which, shifted-right 3 is
device number 9. Why is the card showing up as device 5 instead of 9?

Any ideas (or links to a recent AMIBIOS setup-editing tool)?

Also, does anyone know where I can find the most complete PCI spec?
That would help a lot!