We have intermittent system panics/hangs during boot on IBM HS20 8843 Blades, during boot on IBM HS20 8843 blades, x336, x346, x3550 and x3650 servers. Is there a fix or workaround for this issue?

Issue

There are intermittent system panics/hangs during boot on IBM HS20 8843 Blades, x336, x346, x3550, and x3650 servers due to USB legacy mode support.

Environment

• Red Hat Enterprise Linux 2.1
• Red Hat Enterprise Linux 3
• IBM HS20 8843, x336, x346, x3550, and x3650 systems
• USB Legacy Support set to Enabled in system BIOS

Resolution

This issue occurs when BIOS traps I/O accesses to port 0x60/0x64 that triggers an SMI (System Management Interrupt) and subsequently corrupts a register. The problem exists with both Red Hat Enterprise Linux 3 and Red Hat Enterprise Linux 2.1 x86 (32-bit) releases and in part is due to the fact that ACPI is not fully supported.

If ACPI were supported, a control method would be invoked which disables USB legacy mode very early during the O/S initialization process. The workaround is to either disable the "USB legacy support" in the BIOS or to use the "noapic" as a kernel boot time option. Since Red Hat Enterprise Linux 3 Update 4, the USB legacy mode support can also be safely turned off by using the "usb-handoff" kernel parameter.

At the GRUB boot screen, select the kernel entry you want to change and press 'e' to edit the entry

Select the kernel line with the arrow keys. An example kernel line from GRUB:

kernel /vmlinuz-2.4.21-27.15.ELsmp ro root=LABEL=/

Press 'e' to edit the entry and add the option to the end of the line. For example, to add the "usb-handoff" option:

kernel /vmlinuz-2.4.21-27.15.EL.IT65627smp ro root=LABEL=/ usb-handoff

Press ENTER to save the change.

Press 'b' to boot.

Additional Information

For SMI (System Management Interrupt) info, see the Intel document 82371AB PCI-TO-ISA/IDE Xcelerator PIIX4.

The "noapic" boot option could have performance impacts since the kernel can not perform IRQ load balancing between CPUs.