IRQ Conflicts with PCI Display Adapters
ID: Q129955
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The information in this article applies to:
SYMPTOMS
When you install a Peripheral Component Interconnect (PCI) video adapter
that is configured to use a particular interrupt (IRQ), Windows 95 may
configure it to use another IRQ that is already in use by another device.
CAUSE
PCI devices can share PCI IRQs, but Windows 95 does not support sharing
PCI IRQs with other non-PCI devices (such as an IDE controller).
Windows 95 display drivers do not use an IRQ. However, PCI adapters
request an IRQ for full backward compatibility.
RESOLUTION
Use Device Manager to resolve the conflict by assigning a different IRQ
to one of the conflicting devices.
MORE INFORMATION
This behavior is common to all PCI display adapters, but does not apply to
Industry Standard Architecture (ISA) or VESA Local Bus (VLB) display
adapters.
PCI devices can share IRQs. This behavior is in the PCI specification and
Windows 95 supports it. PCI devices must be configured by the computer's
BIOS. This occurs during the computer's Power-On Self Test (POST) before
the operating system is loaded. Windows 95 does not configure PCI devices,
but uses what the BIOS reports.
In order to get full Plug and Play functionality, Windows 95 enables
inactive devices when it starts. For example, if a second IDE controller
is disabled in the BIOS but not in Device Manager, the controller is
enabled and resources are assigned to it. To prevent this behavior, disable
the inactive device and remove it from the current configuration in Device
Manager.
Note that if you are using an early version of the Micron BIOS, you should
contact Micron for a later version. Early versions of the Micron BIOS do
not configure PCI cards correctly, leading to conflicts with the video
device on IRQ 15 or other non-valid IRQs. To correct this problem, Micron
recommends that you upgrade the ROM BIOS to revision 19. You can obtain
the ROM BIOS flash upgrade from Micron, or from Micron's Web site at:
http://www.mei.micron.com
Download the 90_PM_19.ZIP file from Micron's Web site.
Keywords : win95 wpp95
Version : 95
Platform : WINDOWS
Issue type :