ML350 G6 & Ubuntu 10.4 LTS: reboot doesn’t work

[kuser9]

“reboot” won’t work. The system spins down to the point where it has to hit the reset switch (so to speak) but then just hangs there with the message “the system will reboot now”. “shutdown –P now” doesn’t work either although it’s rarely used.

The firmware is up to date and everything else works like a charm right out of the box.

Any ideas on how to fix that? Are any specific kernel parameters or drivers needed?

[Matti_Kurkela]

Yes, there is a kernel boot option that can be used to select the reboot method used. Logically enough, the option is named 'reboot='.

The possible settings are, as documented in kernel-<version>/arch/x86/kernel/reboot.c:

/*
 * reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
 * warm   Don't set the cold reboot flag
 * cold   Set the cold reboot flag
 * bios   Reboot by jumping through the BIOS
 * smp    Reboot by executing reset on BSP or other CPU
 * triple Force a triple fault (init)
 * kbd    Use the keyboard controller. cold reset (default)
 * acpi   Use the RESET_REG in the FADT
 * efi    Use efi reset_system runtime service
 * pci    Use the so-called "PCI reset register", CF9
 * force  Avoid anything that could hang.
 */

Try all the methods until you find one that works, e.g. for ACPI reboot, "reboot=acpi" or just "reboot=a".

I'm not sure, but I think the option might have been named "reboot_type=" in older kernels. So if "reboot=" does not seem to be having any effect at all, try the longer version of the option name.