Re: PROBLEM: APIC on a Pentium Classic SMP, 2.4.21-pre2 and 2.4.21-pre3 ksymoops

[Maciej W. Rozycki]

On Tue, 9 Sep 2003, Mikael Pettersson wrote:

> Ok, that one is line 295 in io_apic.c. It bombs in 2.4.21-pre{2,3}
> because mp_bus_id_to_pci_bus was changed from a static array to
> a dynamically allocated array. On your machine, smp_read_mpc() in
> mpparse.c doesn't get to the point where it allocates that array,
> so the array is NULL in io_apic.c and you get an oops.

 As I have already written, the system uses a default MP configuration.
smp_read_mpc() isn't called at all.  construct_default_ISA_mptable() is
used instead.

> Fixing the oops is easy (see below), but the real problem is
> that 2.4.21-pre2 apparently broke MP table parsing on your HW.
> I suggest you sprinkle tracing printk()s in setup/smpboot/mpparse
> and compare 2.4.20 (good) and later (bad) to see where things
> start to diverge.

 There is no need to -- the problem is already known.  Mikael, if you need
additional details on how default MP configurations work in our code, feel
free to ask.  Unfortunately, I won't likely be able to do any coding
and/or testing in this area before October.

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@xxxxxxxxxxxxx, PGP key available        +

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