BIOS Setup

PCI/Plug and Play Setup

There is in the setup a menu for the setting of the PCI bus and of the ISA Plug and Play devices, usually called PCI/Plug and Play Setup (or PNP/PCI Configuration). The proper menu setting is important in order to avoid interruptions or DMA conflicts in your computer, specially when you have an old peripheral device installed as for instance a sound board.

Usually when two or more peripheral devices are configured to share the same facility, they don’t work appropriately. When two Plug and Play devices are installed using same facility (same interruption line or DMA channel) the operating system itself may automatically reconfigure the devices in order to solve the facilities conflict.

Old Plug and Play devices are not Plug and Play therefore there is no way to change their settings by means of the operational system (in those type of peripherals the setup is changed by means of jumpers). If a Plug and Play device consistently uses same interruption or DMA channel as a legacy non Plug and Play device, it may happen that the system is unable to manage this conflict permitting that peripheral devices conflict and therefore don’t operate.

Therefore in the computer setup there is how to manually set which interruptions (IRQ) and DMA channels are being used by legacy non plug and play devices. In that way such facilities are set apart by the system and no Plug and Play device may use them.

If you have any legacy non plug and play device installed in the computer – as a sound board or fax modem – you must perform this procedure. Sound boards normally use IRQ5, DMA1, and DMA5 while fax modem uses IRQ3.

The set up is done by means of options such as “IRQ x Available To” and “DMA x Available To”. There are two configuration possibilities: “PCI/PnP” in case the facility is being used by a Plug and Play PCI or PCI device, or “ISA/EISA” (or “Legacy ISA”) when the facility is being used by a non Plug and Play device.

If you have a legacy sound board in your computer, you will have to set “IRQ5 Available To”, DMA1 Available To”, and DMA5 Available To” as “Legacy ISA”, while other options should stay in “PCI/PnP”.

In case you don’t have legacy boards installed, you can just set the option “Resources Controlled By” in Auto to inform all peripherals in your computer are Plug and Play. In case there is at least an installed legacy non Plug and Play board, you must leave this option in Manual and execute the discussed setup.

The existing “PnP OS installed” option must be enabled if you are using Windows 9x.