Home - Products - Buy - About Us - Support - Custom - SiteMap

PCI IRQ Routing in Windows 9x

For best operation of an Elan PCI/PCMCIA drive in Windows 95 and 98, it is recommended that PCI IRQ routing be enabled;  on some motherboards Windows fails to do this correctly and it may be necessary to force the Windows PCI Bus driver to use BIOS calls in order to route PCI interrupts correctly.  This is can be done via Control Panel/System/Device Manager/System devices/PCI bus.

The following screen-shots are from Windows 95, but the procedure is just the same in 98.

To do this, go to Control Panel/System/Device Manager/System devices/PCI bus...

Screen-shot of the 'System Devices' tab in 'Device Manager' which is
accessed through the 'System' section of the Control Panel 

...and click on 'properties'.

 Then click on the IRQ steering tab, and check the boxes to use IRQ steering :

Screen shot of the IRQ steering tab

You can check the results in the IRQ Routing Status panel.

Using BIOS calls.

On some motherboards, Windows fails to enable PCI IRQ routing correctly with direct hardware calls. In this situation, it may be necessary to force the Windows PCI Bus driver to use BIOS calls in order to route PCI interrupts correctly. This is can be done via Control Panel/System/Device Manager/System devices/PCI bus/properties (see above)

Click on the settings tab and check the "Use Bios" button as below:

Screen shot of PCI Bus properties dialog box

NB:  Take care not to check the Override bridges box as this can cause problems.