Very strange issue discovered with pre pnp umb pci motherboards! \ VOGONS

Very strange issue discovered with pre pnp umb pci motherboards!

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First post, by aaronwhooley

Posted on 2023-11-21, 11:48

aaronwhooley Offline

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Hey guys!

I have a 486 umc8810p motherboard, and I have come across a most unusual workaround on this board when one installs a pci network card!

No matter what you try when you simply Insert a pci card and boot into windows 9x it will recognize the card but no matter what driver you install it will fail..

After running the diagnostics it told me that the computer never assigned an Irq! A pci device!? I thought pci was pnp. It is but this bios was made before pnp was a thing!

So to make the card work, in the bios I had to assign an irq to the pci card. Rebooted and hey presto! Worked perfectly.

Hopefully this helps someone else. 😀

*My retro rig*
1994 Peacock 🦚 “Professional”
Intel dx4 100 MHz
UM8810p AIO motherboard
32MB Ram
52x CD-ROM
540 mb Quantum Fireball
AWE 32 ISA
S3 Trio 64 PCI
Voodoo 1 4mb PCI
Realtek LAN PCI
Hyundai Image Quest v770

Reply 1 of 5, by BitWrangler

Posted on 2023-11-21, 18:32

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Yes you may come across this on Pre 1996 boards 486 or Pentium, Intel, UMC, Opti. No PCI no ACPI steering, assign IRQs in CMOS setup.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 2 of 5, by aaronwhooley

Posted on 2023-11-21, 19:38

aaronwhooley Offline

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BitWrangler wrote on 2023-11-21, 18:32:

Yes you may come across this on Pre 1996 boards 486 or Pentium, Intel, UMC, Opti. No PCI no ACPI steering, assign IRQs in CMOS setup.

That’s fascinating! I only happened to ever have pnp Isa/pci boards or old Isa non pnp motherboards. Until now 😅 I was going insane trying all my pci network cards 🤦‍♂️

Reply 3 of 5, by Babasha

Posted on 2023-11-21, 20:30

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Really old PCI motherboards req’s IRQ setup by jumpers on mobo. INTA-INTD assing 😀

Need help? Begin with photo and model of your hardware 😉

Reply 4 of 5, by BitWrangler

Posted on 2023-11-21, 21:35

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Yah, maybe should have remembered that with owning one of these https://theretroweb.com/motherboard/manual/34548.pdf but it's 2 decades since I set it up.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 5 of 5, by aaronwhooley

Posted on 2023-11-21, 23:24

aaronwhooley Offline

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Rank: Newbie
Posts: 17
Joined: 2017-12-04, 08:21

It’s a pretty cool motherboard. And you can tweak timings on each pci slot allowing for even faster graphics performance from the s3 trio64 and along with a voodoo I can get 25fps in tomb raider 😀

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