Checking IRQ Availability

The instructions in this section show you how to determine if the IRQ you requested has been allocated to a device. It also shows you how to determine which IRQs are currently being used, so you can find an unused one for your device.

To determine if your device has an IRQ allocated to it:

Open the RTX Properties Control Panel.
On the Hardware tab, click the Settings button under RTX devices.

Double-click the device whose IRQ you want to view. You see the RTX PCI Device Properties or RTX ISA Device Properties dialog box.
Look in the Status area for information on whether or not the IRQ you requested for this device is available. Possible status messages are provided below:

PCI MSI status messages:

Device is MSI capable and should work for message-based interrupts.
Device is not MSI capable.

PCI line-based status messages:

The [shared/unique] IRQ [IRQ_Number] is available for line-based interrupts.
No IRQ resource is available for line-based interrupts.
The device was unable to get the requested line-based IRQ resource, but was able to acquire [shared/unique] IRQ [IRQ_Number].

ISA line-based status messages:

The IRQ [IRQ_Number] is available for line-based interrupts.
The device was unable to get the requested line-based IRQ resource, but was able to acquire IRQ [IRQ_Number].
No IRQ resource is available for line-based interrupts.

If the requested IRQ is not available, click Cancel in the RTX PCI/ISA Device Properties dialog box, then continue with the next procedure to view a list of currently used IRQs. Use this list to determine which IRQs are available, then edit the properties for this device to use one of the unused IRQs. See Modifying RTX PCI Device Properties or Modifying RTX ISA Device Properties for details.

To view a list of active IRQs:

In the PnP Device Settings dialog box, click the Device Manager button.
In Windows Device Manager, select View > Resources by type.
Expand Interrupt request (IRQ) to see a list of all currently used ISA and PCI interrupts.
When you are finished, choose Exit from the File menu to close the Device Manager.