IRQ sharing and manual assignment

[FKM]

Am having problems installing two NIC cards on my SuperMicro P6DGU m/b -- one D-Link ISA 10bT for cable modem and SMC 100bT for home LAN.

Why does Win98 detect new hardware again when rebooting each time, and what is "IRQ Holder for PCI Steering" in the Device Manager Properties on some of the IRQ's that also have actual devices assigned to them?

[Bleeding Edge]

Your running WIN98 on a dual processor board with a single CPU for the time being? You already did the GX patch and Win98 running good other than what you mentioned.

Can you get the cable modem running without the NIC installed? Remove both devices from Device manager and turn off the computer and pull out just the NIC. Reboot and install the latest drivers for the modem. Get this working first then tackle the NIC. Make sure you got the latest drivers and Bios image for the NIC. When your ready to install the NIC (after you actually do) don't let Win98 search to install the drivers but cancel it. Remove it from Device Manager if it's there. Go to add new Hardware and install it from there. Choose have disk and install the lastest drivers.

Oh. And before all of this check the Autoexec and Config files for any refernce to the NIC. You don't want any 16bit drivers loading before Win98 starts.

IRQ/PCI holding is exactly what the name implies. It holds a IRQ for the PCI device that orignally was intended for a non PnP ISA device and steers the ISA's resource to a different IRQ.

It's a shuffling act Windows performs to reprogram PCI interrupts of PnP PCI and ISA resources around non-PnP ISA devices.


"For example, if your computer's BIOS is unaware of non-Plug and Play ISA cards, the operating system does not have PCI bus IRQ steering, and the BIOS has set a PCI device to IRQ 10, you may have a resource conflict when you add a non-Plug and Play ISA device that is configured for IRQ 10."

"However, with PCI bus IRQ steering the operating system can resolve this IRQ resource conflict. To do so, the operating system:"

"Disables the PCI device.
Reprograms a free IRQ to a PCI IRQ, for example IRQ 11.
Assigns an IRQ holder to IRQ 11.
Moves the PCI device to IRQ 11.
Reprograms IRQ 10 to be an ISA IRQ.
Removes the IRQ holder for IRQ 10. "

[ridefree]

This may not apply to your card but did to my Linksys ISA NIC. It has it's own set up disk to set the IRQ in its onboard EPROM.
Win95 will autoselect an IRQ, but this may not necessarily be the one that the card itself is set to. They must match or it will not work.

BTW the NIC was very particular about what I could assign and I had to work around it's needs and move some PnP devices to accomodate it.

[Jin Vitas]

In lamens terms IRQ steering is basically letting pci devices share one IRQ.

[Bleeding Edge]

Not exactly.

No offense.