Preventing PCI Resource Conflicts on Intel-Based Computers (148501)
The information in this article applies to:
- Microsoft Windows NT Workstation 3.5
- Microsoft Windows NT Workstation 3.51
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Server 3.5
- Microsoft Windows NT Server 3.51
- Microsoft Windows NT Server 4.0
This article was previously published under Q148501 SYMPTOMS
On your Intel-based (x86-processor-based) computer running Windows NT,
after you add another PCI device, the system stops responding (hangs) or
the PCI device may fail to operate.
CAUSE
The Windows NT Hardware Abstraction Layer (HAL) HAL assigned an I/O port
address or memory resource for the new PCI device that overlaps with an
existing PCI device therefore causing a PCI resource conflict on your
system.
Under normal operation, the system BIOS is responsible for setting the PCI
device resource requirements. When Windows NT loads, the Windows NT HAL
sometimes moves the PCI device resources. PCI devices are dynamically
configurable. However, the Windows NT HAL sometimes assigns overlapping I/O
port addresses or memory resources for the PCI devices.
WORKAROUND
To resolve this problem, upgrade to Windows NT 4.0 and follow the
instructions under Windows NT 4.0 Upgrade Information below. To work around
this problem use one of the workarounds below.
Windows NT 4.0 Upgrade Information
Under Windows NT 4.0, an option has been added to the BOOT.INI file that
the x86-based HALs can recognize. Note that only those HALs shipped by
Microsoft will recognize this switch. When a HAL recognizes the /PCILOCK
switch (option), the HAL does not allow the operating system to change
the PCI device resources as long as the system BIOS settings appear to
be correct and complete.
If the adding of a PCI adapter causes a hang during boot, remove the
offending PCI adapter card. Reboot the system and modify the BOOT.INI
file by adding the /PCILOCK option. Shut down the system, add the new
adapter card, and reboot the system.
The Windows NT 4.0 HALs that currently have this fix in are: HAL.DLL,
HALMPS.DLL, and HALAPIC.DLL.
Workarounds
To work around this problem, do one of the following:
- Insert the PCI adapter cards to a different PCI slot. This option does
not apply to PCI devices built in to the main system board
(motherboard).
-or- - Change the driver load order for the conflicting PCI adapters. This is
not always possible when the types of drivers loaded have to be in a
pre-determined order. Be very careful when modifying the registry as an
incorrect setting may cause the system to become unstable or unbootable.
STATUS
Microsoft has confirmed this to be a problem in Windows NT versions 3.5 and
3.51. Microsoft has corrected this problem in Windows NT 4.0 and in the
latest Windows NT 3.51 U.S. Service Pack. For information on obtaining the
Service Pack, query on the following word in the Microsoft Knowledge Base
(without the spaces):
MORE INFORMATION
When you write device drivers for Windows NT, remember that the call to
HalAssignSlotResources is the API that moves the PCI resources. Some
drivers use IoReportResourceUsage, as a HalAssignSlotResources alternative,
with the current resource settings obtained from the configuration space of
the PCI device. The calls to HalGetBusData and HalGetBusDataByOffset can be
used to read the PCI device configuration space. This method should only be
used as a last resort as it contradicts the purpose of having a dynamically
configurable bus.
| Modification Type: | Major | Last Reviewed: | 5/7/2003 |
|---|
| Keywords: | kbHardware KB148501 |
|---|
|