The Haiku/BeOS Tip Server
Tips and tricks for Haiku/BeOS users

Resolving IRQ conflicts

Contributed by: Jace
This tip is valid for: Both BeOS and Haiku

Scenario: You have carefully hand-picked your computer’s components to be compatible with BeOS. You also run a Windows 98/95 installation on the same machine with no problems. Yet, certain devices (USB, SBLive, etc) do not function in BeOS, though they seem to work fine in Windows. Why? Here’s an idea: check to see if your computer is forcing two or more devices to use the same IRQ (Interrupt Request).

For example, Windows95/98 doesn’t have any qualms about allowing the USB controller(s) to share an IRQ with other devices. Things will seem to work (depending on your devices). BeOS, however, runs your hardware “properly.” It may not appreciate IRQ sharing (though IRQ sharing does work in many instances).

If you find you DO have two or more devices sharing an interrupt (you can learn this by open the Devices preferences panel and tapping Alt+U), you may have to remove these devices physically (PCI cards, for example) and rearrange them to incite the mainboard to assign new resources. You may also benefit from disabling older I/O devices you are not using (like IDE on a SCSI system or serial and parallel ports where you will be using USB instead); this will free up more IRQs for other devices.

Thanks for this tip must also go to: Mathias Agopian at Be for helping me check USB in BeOS and Creative Labs’ great technical support for the PCI IRQ info.

Posted in Hardware

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