At 05:24 7/3/99 , Cliff Mark wrote:
 >I am running a P2 350 on BX chipset, ISA SCSI host card for scanner PCI
 >modem and soundcard both IDE channels occupied by Hard disk and CD-R.
 >I am having resource problems. ie. too few IRQ's.
 >I have noticed that under Checkit a motherboard resource called IRQ
 >holder for PCI steering is marked as disabled....
 >Assuming that this is the cause of my resource problems can anyone tell
 >me the function of the IRQ holder? How do I un-disable it?


Hi Cliff

You can take the following steps to ENABLE PCI Steering:

1. Click Start, point to Settings, click Control Panel, and then
    double-click System.
2. Click the Device Manager tab.
3. Double-click the System Devices branch.
4. Double-click PCI Bus, and then click the IRQ Steering tab.
5. Click the Use IRQ Steering check box to put an X in it, click
    OK, and then click OK again.
6. When you are prompted to restart your computer, click Yes.

Check the article "How to Disable PCI Bus IRQ Steering in Windows"
at <http://support.microsoft.com/support/kb/articles/q182/6/28.asp>
for more information on the other options on the IRQ Steering tab
in Device Manager.


Here's a description of PCI Steering that I wrote recently:

In Win95 and Win95a (OSR1), the IRQs assigned to PCI devices by the
motherboard BIOS could not be changed. With Win95b (OSR2), a feature
called "PCI bus IRQ steering" was added which enables Windows to
override the IRQ assigned by the BIOS to a PCI device.

When IRQ steering is enabled, the BIOS still assigns IRQs to PCI
devices, and even though Windows has the ability to change these
settings, it generally does not. But PCI bus IRQ steering gives
OSR2 the flexibility to reprogram PCI interrupts when re balancing
Plug and Play PCI and ISA resources around non-Plug and Play ISA
devices.

For example, suppose your computer's BIOS is unaware of non-Plug
and Play ISA cards and you are using Win95 or Win95a. If 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, Windows can resolve this IRQ
resource conflict. To do so, Windows first disables the PCI device
and reprograms a free IRQ to be a PCI IRQ, for example IRQ 11.
Then it assigns an "IRQ holder" to IRQ 11 and then moves the PCI
device to IRQ 11. Finally it reprograms IRQ 10 to be an ISA IRQ
and removes the IRQ holder for IRQ 10.

An IRQ Holder for PCI Steering may be displayed when you view the
System Devices branch of Device Manager. This indicates that an IRQ
has been programmed to PCI mode and is unavailable for ISA devices,
even if no PCI devices are currently using the IRQ.

Much of the above is from "Description of PCI Bus IRQ Steering" at
<http://support.microsoft.com/support/kb/articles/Q182/6/04.asp>.

Regards,
Bill

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                       Drew Dunn<[log in to unmask]>