IBM Support

"MP-BIOS bug:8254 timer not connected" displayed during boot - Servers

Troubleshooting


Problem

"MP-BIOS BUG:8254 timer not connected to I/O-APIC" message is displayed during boot

Resolving The Problem

Source

RETAIN tip: H186775

Symptom

"MP-BIOS BUG:8254 timer not connected to I/O-APIC" message is displayed during boot.

Affected configurations

The system may be any of the following IBM servers:

  • IBM System x3950, Type 8872, any model
  • IBM System x3950 E, Type 8874, any model
  • IBM xSeries MXE-460, Type 8874, any model
  • IBM xSeries 460, Type 8872, any model

The system is configured with any diagnostics.

The BIOS level(s) affected is/are:

  • any

The Firmware level(s) affected is/are:

  • any
Solution

None.

Workaround

The message should be ignored.

Additional Information

The 8254 is a legacy timer chip which is still emulated in modern hardware for compatibility purposes. Being a legacy device, its default configuration is to delivery a legacy style interrupt to a 8259 PIC controller. With modern SMP systems it is necessary to emulate this behavior by having an I/O-APIC act as an agent to deliver these interrupts to the appropriate destination. There are many ways a system designer may choose to accomplish this task. During the boot process the SLES 9 O/S tries multiple methods to see which one an individual box uses. There various messages which may be displayed as the discovery process continues. SLES 9 does eventually discover the correct method and should present a message "...trying to set up timer as Virtual Wire IRQ... works." Indicating that it succeeded in establishing correct routing for the interrupt. The warnings displayed prior to this can be safely ignored.

Document Location

Worldwide

Operating System

System x:Operating system independent / None

Older System x:Operating system independent / None

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Document Information

Modified date:
29 January 2019

UID

ibm1MIGR-64424

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