Uncertain if quad-core processor recognised

[walawa]

Would a fresh install fix the problem? Could installing 64 bit ubuntu or booting into a LiveCD help?

Perhaps it is certain Bios(es) and certain CPU's that the kernal has trouble with?

Is there a way to reinstall the kernel, or something along those lines?

[blueridgedog]

Well, you might try booting off of the 32 bit and 64 bit live cd and seeing if it sees all four cores.

[walawa]

I'll probably try booting into a 64-bit LiveCD later today. Would compiling a new kernel possibly fix this issue?

[blueridgedog]

I don't think so, but I would verify the kernels you have tried and then submit a bug report:

https://launchpad.net/ubuntu/+filebug

I feel strongly that it is a combination of certain chipsets/bioses/cpus.

[walawa]

It's fixed. System monitor now shows all four cores. The problem was that apic wasn't disabled in the kernel line, but it was in the BIOS setup. I'd already checked the BIOS to make sure all cores were enabled, but I guess I didn't notice the apic option.

Thanks for your help.

[unutbu]

Congratulations, walawa, and thank you for posting your solution!
What did you do differently between now and post #23 when you tried booting with "noapic" ?

[walawa]

In post #23 I was trying to boot with acpi disabled because I'd read it could help, but this did not make a difference because I didn't know that acpi was already disabled in the BIOS. The problem was that I've been booting with acpi disabled without knowing it. So I enabled it and now everything works fine.

[bettlebrox]

Great! Glad you got the 4 cores enabled.

[ectospasm]

It seems to be hit or miss with me. Earlier this month I posted on launchpad, I'm not sure why I didn't post here. My original bug post was marked as a duplicate of this: Bug#97554

And no, disabling APIC is not a viable solution. The way I understand it, that would disable SMP altogether, which is not what I want.