"Latitude with broken BIOS" ?

Quoted 6 lines · Alessandro Suardi

I was hoping to use HT on my new Latitude C640 (P4 @ 1.8Ghz) but at boot both 2.4.21-pre3 and 2.5.59 (obviously with a SMP kernel) tell me

"Dell Latitude with broken BIOS detected. Refusing to enable the local APIC."

Is this anything that can be played with ?

First of all, your 1.8GHz mobile P4 doesn't actually have HT. The only ones to have it are the new 3.06GHz P4s, and most Xeons.

Secondly, I'm responsible for the message you quoted. Many if not all Pentium III-based Dell laptops (including Latitude Cnnn and I8nnn) that have local-APIC capable processors fail miserably if the OS actually enables it. For instance, pulling or inserting the DC power plug would hang the machine. This is a BIOS bug we can't work around, except by refusing to enable the local APIC.

Your P4-based Latitude probably has a different BIOS than the buggy P3-based ones, and it may work better. Try commenting out the local_apic_kills_bios entry for "Dell Latitude" at around line 692 in arch/i386/kernel/dmi_scan.c and rebuild the kernel. If it