Source

RETAIN tip: H187546

Symptom

When a user tries to enter the controllers configuration utility with two or more controllers installed, the system may POST the following error:

1801 PCI Resource Allocation Error
For MegaRAID 8480 controllers, use CTRL-H to access the WebBIOS Configuration Utility.
For the IBM SAS HBA Controller, use CTRL-C to access the WebBIOS Configuration Utility.

Affected configurations

The system may be any of the following IBM servers:

• System x3105, type 4347, any model
• System x3400, type 7973, any model
• System x3400, type 7974, any model
• System x3400, type 7975, any model
• System x3400, type 7976, any model
• System x3500, type 7977, any model
• System x3550, type 7978, any model
• System x3650, type 7979, any model
• System x3755, type 8877, any model

The following system BIOS level(s) are affected:

• MegaRAID 8480 with BIOS version 1.02.00-0089

The system is configured with one or more of the following IBM Options:

• MegaRAID 8480 RAID Adapter, Option part number 39R8850
• SAS HBA Controller, Option part number 25R8060, replacement part number (FRU) 25R8071

This tip is not software specific.

Solution

No specific fix is planned, however, it is suggested to use the latest version of the system BIOS, which may improve ROM space usage. Please refer to the specific system BIOS information and change history for details.

Workaround

If an "1801 PCI resource error" occurs, disable "PCI ROM Control Execution" for the second controller. This will free enough ROM space for both controllers to run properly.

Disabling this option is done within system BIOS setup.

After the system is powered on, press F1 when prompted.

Select the following menu choices:

• Advanced Setup
• PCI Settings
• PCI ROM Control Execution

Within the "PCI ROM Control Execution" Panel, select the slot number for the secondary controller and disable that slot.

Save the new BIOS settings and restart the server.

Additional information

When two or more of the affected controllers are installed, the BIOS for each controller will be allocated system ROM space for execution with default system BIOS settings. It is only necessary for the first controller to load its BIOS into ROM space. This single instance of the respective controllers BIOS will manage both adapters of the same type. By disabling "PCI ROM Control Execution" in the system BIOS for the second controller, less ROM space is used and avoids the BIOS POST event "1801 PCI Resource Allocation Errors" when launching the WebBIOS Configuration Utility.