Messages in this thread | | | Date | Mon, 8 Dec 2003 05:58:59 -0600 | From | Ryan Underwood <> | Subject | Re: APIC support on Slot-A Athlon, K6 |
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> >Unfortunately, this disables the APIC support (if it existed) on a > >Slot-A Athlon 600 MS-6167 (family 6, model 1, AMD-751/756), and a K6/3 400 > >Tyan S1598 (family 5, model 9, MVP3/686A). > > > >What is the purpose of this check? Why is the APIC availability dependent > >on the CPU, rather than just the southbridge? > > This code checks for the ability to enable the local APIC, > which is integrated into the processor. The local APIC is > not implemented in K6 or K7 model 1, so the check is correct.
Thanks, that just cleared up a huge misconception (I had the APIC and I/O-APIC confused, apparently).
This page cleared a lot up (must remember to STFW occasionally): http://www.microsoft.com/whdc/hwdev/platform/proc/IO-APIC.mspx
> Furthermore, I/O-APIC usage requires (in hardware) that the > processor has a local APIC.
What can the APIC support alone accomplish, without an I/O-APIC? Just NMI watchdog and related things? (looking at CONFIG_APIC help) Looks like I/O-APIC is the real desired feature, but a functioning local APIC, though not very useful by itself, is a prerequisite for it.
> > Also, there are only > >checks for Intel and AMD CPUs. Is it not possible to use an APIC in > >conjunction with a Cyrix, et.al. ? > > The other manufacturers haven't yet implemented local APIC > functionality in their processors.
Ok, much more clear.
> >The APIC is also not enabled on this machine, but it is a 586B southbridge,= > > which > >I am not sure contains an APIC. > > What processor? As I wrote above, I/O-APIC can't be used unless > the processor has a local APIC.
Cyrix. :D Obviously, it won't work simply because of that. I am curious if the VIA 586B has a IO-APIC though (the 686A/B do) so that it would work if I put a different processor in it. VIA no longer put their datasheets on the web anymore...
> Some BIOSen have an option for enabling/disabling I/O-APIC mode. > Some BIOSen skip the "legacy" MP tables and only announce the > I/O-APIC config data via ACPI, so working ACPI may be required.
Also useful info. Thanks!
-- Ryan Underwood, <nemesis@icequake.net> [unhandled content-type:application/pgp-signature]
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