Re: Why do so many machines need "noapic"?

From: Phillip Susi
Date: Thu Sep 27 2007 - 18:03:21 EST

Dave Jones wrote:
If memory serves correctly, that was circa 2.6.10, back in these commits..

commit a068ea13d1db406e15c346e93530343f6e70184c
Author: Len Brown <len.brown@xxxxxxxxx>
Date: Sun Oct 10 05:21:08 2004 -0400

[ACPI] If BIOS disabled the LAPIC, believe it by default.
"lapic" is available to force enabling the LAPIC
in the event you know more than your BIOS vendor.

commit 2fcfece90db9643b6f30a7ad343898a2871e6a81
Author: Len Brown <len.brown@xxxxxxxxx>
Date: Sat Oct 9 20:12:45 2004 -0400

[ACPI] Don't enable LAPIC when the BIOS disabled it.
Doing so apparently breaks every Dell on Earth.

But those changes relate to the local APIC, which 'noapic' shouldn't
have any effect on should it ?

If the LAPIC is disabled, then you CAN'T use the IO-APIC right? So then
wouldn't the noapic option have no effects since the apic is already

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at