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17 ColorShot printer telephone support guide
When the USB host controller is enabled by installing the USB supplement as
described in the previous section, it typically installs on IRQ 9, 10 or 11. The
host controller installs itself on the PCI bus using the built-in process called IRQ
steering. With this process, Windows dynamically assigns ("steers") PCI bus
IRQs to PCI devices. The Device Manager often shows the USB host controller
sharing an IRQ with another device. This does not seem to cause problems with
the ColorShot printer.
In rare instances, a PCI board that worked before USB was enabled no longer
works after USB is enabled. When this happens, the Device Manager displays a
yellow exclamation point next to the device that no longer works. This problem
has two workarounds:
Assign another IRQ: Some PCI boards are shipped with utility programs for
assigning an IRQ to the device. These utilities are usually accessed during
startup.
Make another IRQ available: Another IRQ can be made available for the
board by disabling a device that the customer does not use. For example, many
laptop PCs have an infrared port occupying an IRQ. If the infrared port is not
used, the customer can disable its IRQ port through the BIOS setup. After the
system is restarted, that IRQ will be available for other devices.
IRQs for USB
controllers