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.
- 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
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=/
e' to edit the entry and add the option to the end of the line. For example, to add the "
kernel /vmlinuz-2.4.21-27.15.EL.IT65627smp ro root=LABEL=/ usb-handoff
Press ENTER to save the change.
b' to boot.
For SMI (System Management Interrupt) info, see the Intel document 82371AB PCI-TO-ISA/IDE Xcelerator PIIX4.
noapic" boot option could have performance impacts since the kernel can not perform IRQ load balancing between CPUs.