[aklug] Re: Kernel 2.6.15 doesn't have core 2 support

On Thu, 17 Jan 2008, Damien Hull wrote:

> After thinking about it this morning I believe I figured out the problem. I
> had to add the following to the kernel to get Dapper installed.
>
> * noapic
> * nolapic
> * noacpi
> * acpi=off
>
> Once Dapper was installed I had to leave these option in there. When I
> installed 2.6.23-14 the above option were also added in grub. With these
> options /proc/cpuinfo showed only one processor. For some reason I decided to
> take these options out. Once I did that I was able to get two cores in
> /proc/cpuinfo.
>
> This leads me to believe that kernel 2.6.15 might work with the core 2 duo.
> However, it won't work with my motherboard. Not unless I add noapic etc...
>
> Feel free to create me if I'm wrong.

APIC support is the key for x86 SMP systems. A Core2 processor will work
with the 2.4 kernel as long as you have good APIC support on the mainboard.
I have personally run older revs that 2.6.15 on a Core2 with no problems,
and all cores showing.

That said, perhaps I missed it but I didn't see the exact error you got when
you tried to do the install without all these kernel args. What happened?
I suspect you were bit by something else.

Bare in mind that tickless kernels have huge bugs on certain hardware,
especially when combined with HPET timer support. Some ICH7 SATA
controllers aren't recognized by default by the ata_piix driver so a generic
IDE driver gets loaded which doesn't support DMA modes, etc. Stuff like
this can make a kernel appear to not work, even randomly hang during boot.
It can actually work correctly, but you do need to be a bit more explicit
with the kernel args.

With some more information I'm sure you can tweak your setup to more fully
take advantage of your hardware.

         --Arthur Corliss
           Live Free or Die
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Received on Thu Jan 17 13:24:02 2008