Re: [PATCH -tip] x86: do_boot_cpu - check if we have ESR register

From: Cyrill Gorcunov
Date: Wed Oct 22 2008 - 10:52:55 EST


[Ingo Molnar - Wed, Oct 22, 2008 at 04:23:12PM +0200]
|
| * Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote:
|
| > | > - apic_write(APIC_ESR, 0);
| > | > - apic_read(APIC_ESR);
| > | > + if (APIC_INTEGRATED(apic_version[phys_apicid])) {
| > | > + apic_write(APIC_ESR, 0);
| > | > + apic_read(APIC_ESR);
| > | > + }
| > |
| > | i'm wondering - is the server there really that old, that it has no
| > | integrated lapic? I.e. it's an i486 SMP box or so? Or perhaps some
| > | other, weird SMP box?
| > |
| > | Ingo
| > |
| >
| > I was quite wondering too -- it's Xeon server.
| >
| > >From http://lkml.org/lkml/2008/10/20/34
| > >> Hardware: Compaq P4 Xeon server, Broadcom CMIC-WS / CIOB-X2 board.
| > >> Tell me if you need more detailed information.
|
| ah, Compaq - how many CPUs does that box support? If it's 8 or more then
| perhaps they turned off the real local APIC, fudged some chipset glue to
| emulate APIC functionality and thus were able to use 8 or more of these
| chips? The built-in lapic would only go up to 4 CPUs. (or maybe even
| just up to dual, depending on the model)

I have no glue how many cpus it does supposrt :) Maybe Max know.

|
| This reminds us that all the is-integrated-lapic checks still matter
| today.
|
| Ingo
|
- Cyrill -
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